Tachyporinae Revisited: Phylogeny, Evolution, and Higher Classification Based on Morphology, with Recognition of a New Rove Beetle Subfamily (Coleoptera: Staphylinidae)

Simple Summary

The rove beetle subfamily Tachyporinae has been suggested to be polyphyletic for the last half century but there are no previous studies conducting phylogenetic analysis on this group specifically. Here, the most comprehensive tachyporine phylogeny is shown, which again rejects the monophyly of Tachyporinae and its largest tribe Tachyporini. A revised classification of Tachyporinae is proposed here based on observation of morphological characters and their phylogenetic analyses. This backbone phylogeny will be a framework for further evolutionary and ecological studies.

Abstract

Tachyporinae are one of the most phylogenetically problematic subfamilies in the mega-diverse rove beetle family Staphylinidae. Despite its high diversity and abundance in forest micro-environments, with over 1600 species worldwide, several previous studies had refuted the monophyly of this subfamily and its largest tribe, Tachyporini. Based on the results of morphology-based phylogenetic analyses and direct examination of specimens encompassing two extinct and all forty extant genera, a new suprageneric classification of Tachyporinae is proposed here, with the removal of the tribe Mycetoporini into a newly recognized subfamily Mycetoporinae stat. nov. Four tribes with two subtribes are arranged within Tachyporinae sensu nov.: Tachyporini sensu nov. (Tachyporina stat. nov., sensu nov. and Euconosomatina stat. rev., sensu nov.), Vatesini sensu nov., Deropini, and Tachinusini stat. rev., sensu nov. (= Megarthropsini syn. nov.). Urolitus syn. nov. is placed as a junior synonym of Sepedophilus. Additionally, Palporus stat. nov. is raised to a distinct genus from a subgenus of Tachyporus sensu. nov., and †Mesotachyporus syn. nov. is synonymized with the latter. Mycetoporine Bobitobus stat. rev. is resurrected from synonymy with Lordithon sensu nov., and considered as a valid genus. My revised classification provides a novel framework for taxonomic inventories and ecological studies of these groups.

1. Introduction

Staphylinidae, whose members are commonly called rove beetles, is the largest family of the animal kingdom, with an incredible diversity of 65,561 living and 450 extinct species as of 4 March 2021 (A.F. Newton, pers. comm.). Among one extinct and 32 extant subfamilies [1], Tachyporinae is a medium-sized group at the subfamily level and currently comprises 1638 species (28 extinct) of 52 genera (12 extinct) in five tribes as of 9 April 2021 (A.F. Newton, pers. comm.; Appendix A). The family Staphylinidae is so diverse and species-rich, it has been further subdivided into four or five groups of subfamilies [2,3]. The tachyporines have been placed in the Tachyporine Group of subfamilies [4,5]. However, none of these groupings are supported as monophyletic (e.g., [6,7]), and they are all in need of further investigation and proper grouping.

Tachyporinae are distributed throughout all zoogeographical regions except for Antarctica (

Table A1. General overview of Tachyporinae sensu nov. under the new classification.

New Classification	Former Tribal Assignment	Described Species	Distribution
Tachyporini MacLeay, 1825 [40] sensu nov.		510 (†6)	AUS, ETH, MAD, NEA, NEO, OCE, ORI, PAL
-Subtribe Tachyporina MacLeay, 1825 [40] stat. nov., sensu nov.		144 (†4)	NEA, NEO, ORI, PAL
1. Lamprinodes Luze, 1901 [57]	Tachyporini	3	PAL
2. Lamprinus Heer, 1839 [59]	Tachyporini	1	PAL
3. Palporus Campbell, 1979 [61] stat. nov.	Tachyporini	2	PAL; intro. AUS, NEA, OCE
4. Symmixus Bernhauer, 1915 [63]	Tachyporini	2	ORI, PAL
5. Tachyporus Gravenhorst, 1802 [41] sensu nov. [= †Mesotachyporus Gusarov, 2000 [56] syn. nov.]	Tachyporini	136 (†4)	NEA, NEO, ORI, PAL
-Subtribe Euconosomatina Cameron, 1918 [44] stat. rev., sensu nov.		366 (†2)	AUS, ETH, MAD, NEA, NEO, OCE, ORI, PAL
6. Euconosoma Cameron, 1918 [44]	Tachyporini	4	ORI, PAL
7. Sepedophilus Gistel, 1856 [84] [= Urolitus Silvestri, 1947 [54] syn. nov.]	Tachyporini	361 (†1)	AUS, ETH, MAD, NEA, NEO, OCE, ORI, PAL
8. †Palaeosepedophilus Paśnik & Kubisz, 2002 [82]	Tachyporini	†1	Europe (Baltic Sea Coast) [mid-Eocene Baltic amber]
Vatesini Seevers, 1958 [13] sensu nov.		290 (†2)	AUS, ETH, MAD, NEA, NEO, OCE, ORI, PAL
1. Cilea Jacquelin du Val, 1856 [93]	Tachyporini	19	ETH, MAD, NEA, NEO, ORI, PAL
2. Cileoporus Campbell, 1994 [91]	Tachyporini	2	NEO
3. Coproporus Kraatz, 1857 [96]	Tachyporini	229 (†1)	AUS, ETH, MAD, NEA, NEO, OCE, ORI, PAL
4. Coprotachinus Cameron, 1933 [98]	Tachyporini	7	ETH
5. Mimocyptus Cameron, 1919 [101]	Tachyporini	2	AUS, ORI
6. Tachinoporus Cameron, 1928 [11]	Tachyporini	1	ORI
7. Tachinoproporus Cameron, 1928 [11]	Tachyporini	1	ORI
8. Termitoplus Silvestri, 1946 [12]	Tachyporini	1	NEO
9. Vatesus Sharp, 1876 [92]	Vatesini	27	NEO
10. †Procileoporus Yamamoto, 2016 [46]	Tachyporini	†1	Myanmar (mid-Cretaceous Kachin amber)
Deropini Smetana, 1983 [23]		20	NEA, ORI, PAL
1. Derops Sharp, 1889 [105]	Deropini	20	NEA, ORI, PAL
Tachinusini Fleming, 1821 [45] stat. rev., sensu nov.		371 (†7)	AUS, ETH, MAD, NEA, NEO, ORI, PAL
1. Austrotachinus Steel, 1956 [110]	Tachyporini	1	AUS
2. Lacvietina Herman, 2004 [25]	Megarthropsini	9	ORI, PAL
3. Leucotachinus Coiffait & Sáiz, 1968 [111]	Tachyporini	3	AUS, NEO
4. Megarthropsis Cameron, 1919 [101]	Megarthropsini	8	ORI
5. Nepaliodes Coiffait, 1977 [113]	Megarthropsini	2	ORI, PAL
6. Nitidotachinus Campbell, 1993 [109]	Tachyporini	16	NEA, ORI, PAL
7. Olophrinus Fauvel, 1895 [115]	Tachyporini	15	ORI, PAL
8. Peitawopsis Smetana, 1992 [116]	Megarthropsini	3	PAL
9. Pseudotachinus Cameron, 1932 [117]	Tachyporini	5	ORI, PAL
10. Tachinomorphus Kraatz, 1859 [118]	Tachyporini	21	AUS, ETH, MAD, NEA, ORI, PAL
11. Tachinoplesius Bernhauer, 1936 [120]	Tachyporini	9	ETH
12. Tachinus Gravenhorst, 1802 [41]	Tachyporini	273 (†1)	NEA, NEO, ORI, PAL
- Subgenus Latotachinus Ullrich, 1975 [121]	Tachyporini	7	PAL
- Subgenus Tachinoderus Motschulsky, 1858 [123]	Tachyporini	60	NEA, ORI, PAL
- Subgenus Tachinus Gravenhorst, 1802 [41]	Tachyporini	204 (†1)	NEA, NEO, ORI, PAL
13. †Hesterniasca Zhang, Wang & Xu, 1992 [124]	N/A	†2	China (Lower Cretaceous) *
14. †Mesotachinus Tikhomirova, 1968 [50]	N/A	†3	Kazakhstan (Middle–Upper Jurassic) *
15. †Protachinus Cai, Yan, Beattie, Wang & Huang, 2013 [52]	Tachyporini	†1	Australia (Upper Jurassic) *
Tachyporinae, incertae sedis		†3
1. †Abscondus Tikhomirova, 1968 [50]	N/A	†2	Kazakhstan (Middle–Upper Jurassic) *
2. †Tachyporoides Tikhomirova, 1968 [50]	N/A	†1	Kazakhstan (Middle–Upper Jurassic) *
TOTAL: 36 (†7) genera		1194 (†18)

The data shown here is based on an unpublished database compiled by A. F. Newton (FMNH), with permission (as of 4 March 2021). See also Appendix A for a note on the species number of Latotachinus. Abbreviations: AUS, Australia; ETH, Ethiopian; MAD, Madagascar; NEA, Nearctic; NEO, Neotropical; OCE, Oceanic; ORI, Oriental; PAL, Palaearctic. N/A: not applicable. The bold numers indicate a total number of species in each family-group category. * The fossil taxa indicated here with the asterisks are compression fossils.

and

Table A2. General overview of Mycetoporinae stat. nov. (members of the former Mycetoporini in Tachyporinae) under the new classification.

New Classification	Former Tribal Assignment	Described Species	Distribution
1. Bobitobus Tottenham, 1939 [140] stat. rev.	Mycetoporini	34	NEA, ORI, PAL
2. Bolitobius Leach, 1819 [141]	Mycetoporini	21	PAL; intro.? NEA
3. Bolitopunctus Campbell, 1993 [33]	Mycetoporini	2	NEA
4. Bryophacis Reitter, 1909 [144]	Mycetoporini	12	NEA, PAL
5. Bryoporus Kraatz, 1857 [96]	Mycetoporini	37	ETH, NEA, NEO, ORI, PAL
6. Canariobolitobius Schülke, 2004 [146]	Mycetoporini	1	PAL
7. Carphacis Gozis, 1886 [148]	Mycetoporini	16	NEA, PAL
8. Ischnosoma Stephens, 1829 [150]	Mycetoporini	118	AUS, ETH, NEA, NEO, ORI, PAL
9. Lordithon Thomson, 1859 [136] sensu nov.	Mycetoporini	97 (†4)	AUS, NEA, NEO, ORI, PAL
10. Mycetoporus Mannerheim, 1831 [137]	Mycetoporini	88 (†1)	NEA, PAL
11. Neobolitobius Campbell, 1993 [33]	Mycetoporini	1	NEA
12. Parabolitobius Li, Zhao & Sakai, 2000 [152]	Mycetoporini	13 (†1)	PAL
13. †Cuneocharis Ryvkin, 1990 [153]	N/A	†1	Russia (Upper Jurassic) *
14. †Glabrimycetoporus Yue, Zhao & Ren, 2009 [154]	Mycetoporini	†1	China (Lower Cretaceous) *
15. †Ryvkinius Herman, 2001 [67]	N/A	†1	Russia (Upper Jurassic) *
16. †Undiatina Ryvkin, 1990 [153]	N/A	†1	Russia (Upper Jurassic) *
TOTAL: 16 (†4) genera		444 (†10)

The data shown here is based on an unpublished database compiled by A. F. Newton (FMNH), with permission (as of 4 March 2021). Abbreviations: AUS, Australia; ETH, Ethiopian; NEA, Nearctic; NEO, Neotropical; ORI, Oriental; PAL, Palaearctic. N/A: not applicable. The bold numers indicate the total numbers of genera and species in Mycetoporinae. * The fossil taxa indicated here with the asterisks are compression fossils.

). At the genus level, many have relatively wide distributional ranges, as listed in Table A1 and Table A2. Interestingly, Leucotachinus Coiffait & Sáiz is distributed disjunctly in South America and Australia, showing a Gondwanan relictual distribution similar to that of the Glypholoma rove beetles [8], Lampriminae stag beetles [9], and moss bugs (Hemiptera: Coleorrhyncha) [10]. In contrast, the members of the current tachyporine tribe Mycetoporini indicate more or less Palearctic or Holarctic distributions, although there are a few cosmopolitan genera (Table A2). Similarly, several genera are limited to one biogeographic region as seen in Vatesus Sharp and Olophrinus Fauvel (Table A1). Many genera are rarely collected, sometimes represented only by a handful of occurrences from the original descriptions (e.g., [11,12]). There are still many undescribed species globally, especially within the genera Sepedophilus Gistel, Tachinus Gravenhorst, or Coproporus Kraatz. Therefore, more new species will continuously be described in the future.

Tachyporines are abundant and frequently encountered in forest-associated environments. A characteristic morphological feature is their tapered abdomen as compared to other rove beetles, so they are rather easily recognized to subfamily in insect inventories, faunal investigations, and ecological surveys. Nevertheless, little has been known regarding their biology and ecological habits, though some are thought to be mycophagous or active predators on other arthropods [3]. Most tachyporine species are small to medium in size, commonly found in micro-environments, such as leaf litter, fungi, bark, or dead wood (Figure 1). The genus Vatesus (Figure 1A,B) is famous for its myrmecophilous lifestyle with army ants in Neotropical rain forests [13,14]. Such remarkable ecology resulted in modifications of the overall body structures, including an exaggerated limuloid morphology with a hugely expanded pronotum that has protective functions against worker ants [15]. A few members, e.g., Derops Sharp or Nitidotachinus Campbell, are found in very wet conditions, often along rivers and streams [16]. Sepedophilus has been targeted by evolutionary studies as its feeding habit switches between predatory and mycophagy within the genus for both larvae and adults [17,18]. A recent study suggests that some members of Sepedophilus may be effective pollinators of two Japanese plant species of Arisaema (Araceae) because of their extremely high visitation frequency [19].

Five tribes are currently included in Tachyporinae [20]: Deropini Smetana, Megarthropsini Cameron, Mycetoporini Thomson, Tachyporini MacLeay, and Vatesini Seevers. Although Herman [21] recognized two more tribes, i.e., Symmixini Bernhauer and Cordobanini Bernhauer, within Tachyporinae, the former is now synonymized under Tachyporini [22], and the latter has been transferred to the subfamily Aleocharinae [20]. Three tribes, namely Deropini, Megarthropsini, and Vatesini, are each monogeneric or containing a small group of distinctive tachyporines, resulting focused taxonomic investigations [13,23,24,25]. A number of systematic studies on the remaining tribes of Tachyporinae have been published, but they are mostly restricted geographically and/or taxonomically. One of these tribes, Tachyporini, is by far the largest tribe with more than 1000 species, comprising the vast majority of Tachyporinae in terms of the number of species.

In spite of their high species richness, Tachyporinae are known as one of the most problematic subfamilies in Staphylinidae, because they are likely a non-monophyletic, and probably polyphyletic, lineage ([3]: Figure 14.30). In fact, several phylogenetic analyses have refuted the monophyly of Tachyporini, Tachyporinae, and even the Tachyporine Group. Non-monophyly of Tachyporinae has been suggested since mid-1970s [26], but Ashe & Newton [27] first indicated the polyphyly of Tachyporinae and Tachyporini on the basis of 27 larval characters with limited taxon sampling. Later, Herman [25] used a phylogenetic approach to examine the internal relationships of the genera of Megarthropsini and assessed the tribe’s systematic position among the other tachyporine tribes. In his tree, the monophyly of Tachyporini was unsupported based on 19 adult characters with very limited taxon sampling [25]. Notably, the Tachyporini genus Coproporus formed a sister group with the Vatesini genus Vatesus in both Ashe & Newton [27] and Herman [25]. Recent molecular studies with extensive taxon sampling of Staphylinoidea have significantly contributed in clarifying internal phylogenies within Staphylinidae and also Tachyporinae. McKenna et al. [6] proposed one of the largest phylogenetic trees of Staphylinidae including three tachyporine tribes, i.e., Deropini, Tachyporini, and Mycetoporini. As a result, Deropini and Tachyporini were recovered together, sister unexpectedly to the carrion beetle family Silphidae, but quite distant from the monophyletic Mycetoporini [6]. Similar results were also obtained in the largest phylogenies of Staphylinoidea [7], in which Vatesus (Vatesini) was clustered with Deropini and Tachyporini. In spite of the dense taxon sampling in these two studies, no representative of Megarthropsini was included [6,7].

One of the major reasons for a lack of comprehensive tachyporine phylogeny is the difficulty of taxon sampling. Members of Tachyporini are frequently encountered, but belong mostly to the four larger genera, i.e., Sepedophilus, Tachinus, Coproporus, or Tachyporus Gravenhorst. Many other genera are rarely collected, some with only handful of records including the original descriptions. This led to insufficient taxon sampling in phylogenetic studies of the subfamily. Additionally, many of the tachyporine genera have not been adequately explored morphologically, resulting in a significant lack of information useful to constructing phylogenetic trees or generic identification aids. Since there is no previous study targeted at inferring the phylogeny of the entire Tachyporinae subfamily, a large-scale phylogeny of this subfamily including all five tribes is not available at the present, but it is strongly desired in order to determine whether Mycetoporini is a true member of Tachyporinae. To address these issues, I tried to test the monophyly, assess sister group relationships with and within Tachyporinae, and provide a new framework for the subfamily. Herein, the first comprehensive phylogeny and a fully updated higher classification of Tachyporinae are provided based on results of phylogenetic analyses of adult morphological characters and direct examination of specimens encompassing two extinct and all forty extant genera. Finally, several fossil genera with uncertain systematic placements are incorporated into proper taxonomic categories. By reducing phylogenetic uncertainty, my study will contribute to the basic foundation for taxonomic, ecological, and evolutionary studies in the mega-diverse Staphylinidae tree of life.

2. Materials and Methods

2.1. General Outline of Study

The main focus of the present study was to provide a backbone phylogeny of Tachyporinae and to assess sister group relationships of or within the subfamily. Despite the importance of genomic data, I decided to use only adult morphological characters here. One of the reasons is the difficulty of collecting samples from various tachyporine genera. Because the tachyporines include so many rare taxa, it would be quite challenging to obtain molecular samples or even conventional dried, pinned specimens for these taxa. Larval characters generally contain vital information for morphology-based phylogeny in rove beetles (e.g., [2,28,29]). However, the larvae of Tachyporinae are far from adequately understood, resulting in a significant lack of larval information for most genera of Tachyporinae. Even within large genera such as Sepedophilus, Coproporus, or Tachinus, accurate identifications of species considering the larva-adult associations are generally difficult, with a high degree of uncertainty in identification. Taking these conditions into account, my morphological dataset is derived from four different sources: (i) pinned specimens, (ii) wet specimens preserved in 70–80% EtOH (ethyl alcohol) solution, (iii) permanent slide specimens, and (iv) literature (Supplementary Files S1 and S2). Therefore, it was possible to include as many extant tachyporine genera as possible in this study. As Tachyporinae may be a polyphyletic lineage, this approach is currently the best strategy to infer the higher-level phylogeny by reducing the number of potentially phylogenetic “distinct” taxa, i.e., each could represent as own higher-taxonomic category (e.g., tribe). The morphological definition for each tribe has not been well established, thus a morphology-based approach is also desired to solve this issue, rather than relying on a smaller taxon sampling based on molecular data, but such a DNA-oriented study is desired in future.

2.2. Taxon Sampling and Deposition of Material

All forty extant genera in five tribes of Tachyporinae were used in this study. Although two very rare genera, Tachinoporus Cameron and Tachinoproporus Cameron, were not included in the formal phylogenetic analyses, the type specimens of these taxa were examined and are redescribed below. This is because I could only observe a subset of the characters from dorsal and lateral views, with limited dissected body parts. The dissected parts were generally covered with glue or distorted, and it may have caused erroneous scoring of characters. Therefore, I decided to remove these two taxa from the analyses, but the outline of Tachyporinae still can be drawn without the inclusion of these two taxa. For most terminal taxa in phylogenetic analyses, morphological data were obtained at least partially from direct observation, with the exception of Urolitus Silvestri (from literature only). In addition, two fossil tachyporine genera, namely †Mesotachyporus Gusarov and †Procileoporus Yamamoto, were directly examined based on the holotypes of each type species, whereas the remaining eight fossil genera were studied from references to evaluate their systematic assignments.

A total of 70 operational taxonomic units (OTUs) were scored for the cladistic analyses, comprised of 57 species in 38 genera of Tachyporinae and 13 representatives of ten other selected subfamilies of Staphylinidae, together with one Silphidae (subfamily Silphinae), as outgroups (Supplementary Files S1 and S2). At least one representative for each subfamily of the Tachyporine Group was included: Aleocharinae, Habrocerinae, Olisthaerinae, Phloeocharinae, and Trichophyinae. More outgroups were carefully chosen based on the results of McKenna et al. [6] and Lü et al. [7], namely Neophoninae, Omaliinae, Osoriinae, Pseudopsinae, Staphylininae, and Silphidae.

Material from the following collections was examined: American Museum of Natural History, New York, USA (AMNH: D. Grimaldi); Field Museum of Natural History, Chicago, IL, USA (FMNH: C. Maier, J. Snyder, or A. F. Newton for wet and slide collections); Kyushu University Museum, Fukuoka, Japan (KUM: M. Maruyama); Muséum d’histoire naturelle de Genève, Geneva, Switzerland (MHNG: G. Cuccodoro); National Museum of Nature and Science, Tsukuba, Japan (NSMT: S. Nomura, private collection); Natural History Museum, London, London, UK (BMNH: M. Geiser); Natural History Museum Vienna, Vienna, Austria (NHMW: H. Schillhammer).

The original higher classification follows Bouchard et al. [20]. A complete list of the taxa used with their collecting data is shown in Supplementary Files S1 and S2. To enhance the understanding the morphological details of Tachyporinae, a series of photographs is shown in the paper.

2.3. Microscopy, Imaging, Measurements, and Terminology

Observations of dry and wet specimens and some permanent slides were made under a Leica MZ16 stereomicroscope (Leica Microsystems, Wetzlar, Germany). Amber fossils were examined using either a Leica MZ16 or a Nikon SMZ1500 stereomicroscope (Nikon, Tokyo, Japan) in air, without immersion in oil or similar liquid. Photographs of dry specimens were taken using an EOS 80D digital camera (Canon, Tokyo, Japan) mounted on an extreme macro lens (Canon MP-E 65 mm, F2.8, 1–5×; Canon) with a flash (Canon Macro Twin Lite MT-24EX Flash; Canon) as light source. The dissected body parts of Tachinoproporus were photographed with the Dun Ink BK PLUS Lab System (Dun, Palmyra, VA, USA) attached to a 6D digital camera (Canon) and a 10× lens. A single amber fossil of †Mesotachyporus was photographed by David Grimaldi (AMNH) using a Nikon Digital Sight DS-R1i camera (Nikon, Tokyo, Japan) as an attachment of a Nikon SMZ1500 stereomicroscope. Slide specimens were imaged using an EOS 80D camera and an AmScope CA-CAN-SLR Canon SLR/DSLR Camera Adapter for Microscopes (AmScope Microsystem, USA), mounted on an Olympus BX50 stereomicroscope (Olympus Corp., Tokyo, Japan). Montage images were later produced using Helicon Focus 7.5.4 (Helicon Soft, Kharkiv, Ukraine), but †Mesotachyporus images were optimized with NIS-Elements D (Nikon). All images were edited and assembled in plates in Photoshop Elements 15 (Adobe Systems, San Jose, CA, USA). The measurements are given in millimetres. The total body length was measured from the apex of the clypeus to the posterior end of the abdomen. The maximum lengths were measured in the head, pronotum, and each elytron (elytral lengths were measured from each elytron with the maximum lengths and widths). The ratios of elytral length and width were calculated basically based on dissected specimens. Some diagnostic characters are indicated with arrows and/or character numbers on the figures. For descriptions and character list, I generally followed the morphological terminology of Blackwelder [30], Herman [25], and Ashe [28]. The age of Baltic amber is controversial from middle to late Eocene, but I followed the mid-Eocene (Lutetian: 44.1 ± 1.1 Ma) age in this study based on the most recent estimations obtained by the absolute dating analyses of glauconites from the “Blaue Erde” (blue earth) layer in Sambia Peninsula [31]. The higher-resolution figure plates used in this study have been deposited in the figshare (https://doi.org/10.6084/m9.figshare.14179529; accessed on 9 April 2021) and Zenodo repositories (https://doi.org/10.5281/zenodo.4660863; accessed on 9 April 2021). This published work has been registered in ZooBank, with the following LSIDs (Life Science Identifiers): urn:lsid:zoobank.org:pub:8F45A3EA-4193-49D3-BF57-A65332D3262C.

2.4. Selection of Characters

One of the most challenging points in constructing the tachyporine phylogeny based on morphology is the selection of characters. Since there is no study specifically focused on the entire Tachyporinae with dense sampling of taxa and characters, I needed to extract some characters from the literature treating mainly non-Tachyporinae such as Ashe [28] or Grebennikov & Newton [2]. Consequently, most characters used here are new and original for Tachyporinae. Some characters used in generic identification were not adopted in this study such as the conditions of spines at the apices of the meso- and metatibiae, pronotal chaetotaxy, or the basomedial carina of the scutellum in Mycetoporini (e.g., [32,33]) because of the significant variations found in a broad set of the outgroups and difficulty to accurately assess these characters in Tachyporinae s. str. Accordingly, this study intended to reveal the relationship between Mycetoporini and the rest of Tachyporinae, and the internal tribal relationship in Tachyporinae s. str., rather than the generic relationships within Mycetoporini.

As a result of my extensive morphological investigations on Tachyporinae and the other staphylinoid outgroups, the final character list is comprised of a total of 156 binary and multi-state characters, taken from various parts of the adult body: 18 from head, 4 from antennae, 26 from mouthparts, 56 from thorax and legs, 36 from abdomen, and 16 from genitalia (10 from male, 6 from female). To evaluate generic level characters, possible autapomorphies for some genera were also included. In the present paper, I also aim to provide morphological resources for diagnostic key characters in Tachyporinae. Thus, habitus photographs representing all extant genera are shown here, together with diverse characters across all body parts of the selected taxa and their associated type-specimen labels for some taxa. The complete list of characters with explanations and post-evaluations is given in the Appendix B.

2.5. Phylogenetic Analyses

The character matrix was created in Mesquite version 3.61 [34], with missing character states coded as ‘?’. My final data matrix included 156 characters scored for 70 terminal taxa (57 ingroup Tachyporinae, 13 non-tachyporine outgroups). The nexus formatted file containing the character matrix with the resulting phylogenetic trees is provided in Supplementary File S3, with the addition of TNT format matrix as Supplementary File S4. In all analyses, Lispinus quadripunctulus Fauvel, 1864 [35] (Osoriinae: Thoracophorini) was chosen to root the trees, considering the results of McKenna et al. [6]. This decision seems to be reasonable after testing different outgroups to root the trees as L. quadripunctulus resulted in smallest number of trees. The software TNT version 1.5 [36] was used for maximum parsimony (MP) analysis using the ‘New Technology search’ option to find the most parsimonious trees (MPTs) with all characters treated as unordered and equally weighted. In order to estimate branch support on a cladogram, I calculated Bootstrap support values generated via TNT version 1.5 under the following parameters: memory set to hold 99,999 trees; slack for sectors set to 80 by entering a command line, “sect:slack 80”; ‘absolute frequencies’ under ‘new technology search’ option with 2000 replications, collapsing groups below 1. Character distributions were mapped using WinClada version 1.00.08 [37]. Nodes with bootstrap values were considered with the following criteria: bootstrap values (BV) > 90 were judged to be strongly supported; with BV = 90–70 moderately supported; with BV = 70–50 weakly supported, and; with BV < 50 unsupported.

3. Results

3.1. Phylogenetic Analyses

3.1.1. Maximum Parsimony Analysis

Maximum parsimony analysis yielded only three most parsimonious trees, each with the following characteristics: tree length (TL) = 977, consistency index (CI) = 0.38, and retention index (RI) = 0.78. The resulting trees were largely congruent with previous studies, although many nodes were weakly supported or not supported. A strict consensus tree is shown here as the representative of the result (TL = 981, CI = 0.37, RI = 0.77; Figure 2, Figure 3 and Figure 4).

As in earlier studies [6,7], Tachyporinae were found to be polyphyletic and divided into two distant clades: one consisting of Mycetoporini (Figures 2–4, clade B in Figures 3 and 4) and the other containing the rest of the remaining tachyporines (Figures 2–4, clade D in Figures 3 and 4). Mycetoporini formed a sister group to Olisthaerus Dejean (Olisthaerinae; Figures 2–4, clade A in Figures 3 and 4) with moderate support, and these two combined was found to be sister to Quedius Stephens (Staphylininae). The Mycetoporini clade was strongly supported as a monophyletic group (Figure 3). Within Mycetoporini, two genera combined, i.e., Parabolitobius L.-Z. Li, M.-J. Zhao & Sakai + Bolitobius Leach, were revealed as sister to the rest of the mycetoporines. However, this relationship was not statistically supported (Figure 3). Lordithon Thomson was found to be polyphyletic (Figure 2), whereas Bryoporus Kraatz formed a monophyletic group (Figures 2–4).

Tachyporinae, in the narrow sense, was also resolved as a monophylum with moderate support value (Figures 2–4, clade D in Figures 3 and 4), forming a sister group to Silpha Linnaeus (Silphidae) with weak support (Figures 2–4, clade C in Figures 3 and 4). The genera with more than two species included in the analysis were recovered as monophyletic, except that the enigmatic Urolitus nigeriensis and Tachyporus nitidulus (Fabricius) came out within Sepedophilus and outside Tachyporus, respectively, as in Figure 2. The tribe Tachyporini was shown here to be paraphyletic, divided into a total of nine clades (Figure 2). Two tribes, Vatesini and Megarthropsini, were each found to be monophyletic, but were resolved within parts of the paraphyletic Tachyporini (Figure 2). Tachyporini sensu str. (Figures 2–4, clade E in Figures 3 and 4), which contains the type genus Tachyporus, formed a sister group to the other Tachyporinae lineage comprised of Vatesini, Deropini, and Megarthropsini, and the rest of Tachyporini. Tachyporini sensu str. was moderately supported and divided into two clades, i.e., the unsupported Tachyporus-related genera (Figures 2–4, clade G in Figures 3 and 4) and the strongly supported Sepedophilus-related genera (Figures 2–4, clade F in Figures 3 and 4). This clade (clade E in Figures 3 and 4) is the moderately supported sister group of the weakly supported clade H (Figure 3), which includes Deropini and Megarthropsini in addition to the some Tachyporini genera related to Coproporus (Figures 2–4, clade I in Figures 3 and 4). Vatesus, the sole member of Vatesini, was strongly supported as monophyletic, belonging in the weakly supported clade I. In clade I, Cileoporus Campbell first diverged within this clade, followed by Cilea Jacquelin du Val, and Vatesus (Figures 2–4). The monophyletic Coporoporus formed a sister group relationship with Termitoplus (Figures 2–4). Subsequently, clade I was recovered as a sister group to clade K (Figures 3 and 4), wherein Deropini (clade L in Figures 3 and 4), Megarthropsini (clade P in Figures 3 and 4), and the remaining Tachyporini with the Tachinus-related genera were nested within it (Figures 2–4). Within clade M (Figures 3 and 4), Nitidotachinus Campbell was a sister taxon to all other members of this clade, and the strongly supported Megarthropsini (clade P in Figures 3 and 4) was resolved within it. Clade M (Figures 3 and 4) was further divided into two subclades: typical members of Tachinus and its allies (clade N in Figures 3 and 4) and atypical ones (clade O in Figures 3 and 4). Deropini was strongly supported as monophyletic, but the clade K (Figures 3 and 4) resulting from the combination of Deropini and clade M (Figures 3 and 4) has moderate support, and clade M alone was unsupported as were all but two of its included suprageneric subclades (Figures 2–4). Contrary to Herman [25], I found that Deropini is distantly related to Megarthropsini, rather than forming sister groups (Figure 2), although a direct comparison between the studies is difficult because of the different study design and taxonomic sampling. Based on observation of morphological characters and their phylogenetic analysis, a new classification is proposed, as shown in Figure 5.

3.1.2. Character Optimization

The unambiguously optimized characters were mapped in Figure 4. Clade A (Figures 3 and 4), the sister group relationship between Olisthaerus (Olisthaerinae) and Mycetoporini was supported by two unique synapomorphies (71-2, elytra with three rows of setigerous punctures; 132-3, sternite VIII in posterior half covered with short to long setae in V-shaped punctures) and seven homoplasious synapomorphies. The distant tachyporine tribe Mycetoporini (clade B) was supported by two exclusive synapomorphies (98-2, metacoxae markedly large in each lateral half; 149-2, parameres each with a row of parameral setae at least partially aligned) and nine non-exclusive synapomorphies. Clade C (Figures 3 and 4), Silpha (Silphidae), and its inferred sister taxon to the remaining tachyporine genera was supported by one exclusive synapomorphy (67-2, mesospiracular peritremes (sensu Blackwelder [30]: Figure 3A,E) fully sclerotized, conspicuous and six non-exclusive synapomorphies. The true tachyporines, i.e., clade D (Figures 3 and 4), were supported by five unique synapomorphies (11-1, midcranial suture present; 117-3, female tergite VIII with lobes; 143-2, parameres with apical inner margins only narrowly separated longitudinally from each other; 154-0, gonocoxite II small in comparison with gonostylus; 155-1, gonocoxite II covered with curved setae) and nine homoplasious synapomorphies. Within clade (D) Tachyporini sensu str. (clade E in Figures 3 and 4) showed a sister group relationship to the remaining tachyporine members except Mycetoporini, and was supported by ten non-exclusive synapomorphies, such as strikingly densely setose maxillary palpomere 3 (32-1), pubescent ground microsetae on elytra (74-2), and tergites IV–V with macrosetae on posterolateral edges (109-1). Two subclades of clade E were the Sepedophilus-related genera (clade F in Figures 3 and 4) and Tachyporus and its relatives (clade G in Figures 3 and 4): the clade F was supported by three unique synapomorphies (e.g., 97-1, protibia with longitudinal row of closely spaced spines along outer margin; 124-2, abdominal segments V–VI without paratergites) and seven homoplasious synapomorphies (clade F), whereas the clade G (Figures 3 and 4) was supported by six homoplasious synapomorphies only (e.g., 57-1, pronotum with arranged stout setae; 75-1, elytron with macrosetae on median area; 125-0, sternite III without longitudinal median basal carina). Clade H was a relatively large monophylum which includes the members of Vatesini, Deropini, Megarthropsini, and the rest of Tachyporini, and it was supported by four unique synapomorphies (114-1, tergite VIII with only a few to several distinct macrosetae; 123-2, male tergite IX with only single to several prominent macrosetae, restricted to apex; 133-1, sternite VIII with only a few to several distinct macrosetae; 137-3, female sternite VIII with lobes, including small internal lobes) and one homoplasious synapomorphy. Clade I was comprised of Vatesini and the Coproporus-related genera of Tachyporini, supported by nine non-exclusive synapomorphies, including only weakly developed postcoxal process with rounded apex behind procoxae (61-1), thin, blade-like lateral and posterior margins of elytra (82-1), and distinctly large procoxae (96-3). Clade K (Figures 3 and 4), a sister group relationship between Deropini (clade L) and clade M, was supported by two exclusive synapomorphies (130-2, male sternite VII with moderately to strongly concave posteromedial margin; 131-2, male sternite VII with more than several to dozens of peg-like setae along posteromedial margin) and seven non-exclusive synapomorphies. Within clade K, Deropini was well supported by six unique synapomorphies (12-4, middle of postocular area distinctly narrowed, all around; 32-3, maxillary palpomere 3 completely glabrous; 49-1, pronotum moderately constricted in posterior half; 51-2, pronotum with uniform punctation dense, but shallow in apical half; 128-1, sternite VII along basomedial margin with a broad, semicircular protrusion; 135-3, male sternite VIII with posterior margin deeply incised or strongly emarginate medially) and additionally by 16 homoplasious synapomorphies. Compared to Deropini, its sister clade M (Figures 3 and 4), comprised of Megarthropsini and the Tachinus-related genera of Tachyporini, was weakly supported by only three non-exclusive synapomorphies, namely: 58-1, pronotum with transverse cluster of blackish to blackish brown, conspicuous small pores near posterior margin (Figure 54G); 138-4, female sternite VIII having both prominent lobes and inner lobes with rows of more than three, minute sensory setae in fan-like arrangement, located in apical area of each inner lobe; 151-1, spermatheca well sclerotized, comparatively complex or distinctively complicated structure, usually associated with coils. Megarthropsini (clade P in Figures 3 and 4) formed a sister clade to the genus Austrotachinus Steel. Clade P was supported by two unique synapomorphies (3-3, head with large punctation uniformly on vertex; 5-2, head with moderately rough or tuberculate surface) and eight homoplasious synapomorphies.

3.2. Systematic Part

Order Coleoptera Linnaeus, 1758 [38]

Superfamily Staphylinoidea Latreille, 1802 [39]

Family Staphylinidae Latreille, 1802 [39]

3.2.1. Subfamily Tachyporinae MacLeay sensu nov.

Tachyporinae MacLeay, 1825: 49 [40] (Figures 1A–D, 2–61 and Figures S1 and S2B; Table A1)

Type genus: Tachyporus Gravenhorst, 1802 [41]: 124.

Differential diagnosis: Tachyporinae sensu. nov. differ from all other subfamilies of Staphylinidae based on the following combination of characters: body usually sub-limuloid, head small usually with midcranial suture, mandibles without inner teeth, elytron with epipleural keel folded inward, procoxae large, tarsal formula 5-5-5, abdomen with six visible sternites lacking ‘brick-wall’ pattern on intersegmental membranes, tergite VIII and sternite VIII frequently modified to form lobes.

Emended diagnosis: Body usually more or less sub-limuloid (e.g., Figure 6A–D,F, Figures 14, 21, 22, 48, 49 and 57A–C,F), except Deropini (Figure 43) and Nepaliodes (Figure 57D,E); head small, not elongate, with midcranial suture in most taxa (e.g., Figure 7A, mcs: 11-1), lacking distinct neck constriction; antennal insertion more or less visible from above, located anterior to eye (e.g., Figure 50B: 9-0, 10-0); antennae not extremely slender and verticillate; mandibles without inner teeth (e.g., Figure 9B: 26-0, 27-0); maxillary palpus 4-segmented; labial palpus 3-segmented; ligula large, as long as wide to transverse (e.g., Figures 45B and 53D,E,G: 44-0, 45-1); mesospiracular peritremes well sclerotized (e.g., Figures 18A and 27E, msp: 67-2); elytron with epipleural keel, lacking longitudinally raised sutural edge (e.g., Figures 51A,C and 52C: 78-0, 80-0); procoxa large, prominent (e.g., Figures 12A, 24C and 29A: 96-3); metacoxae with developed ventral lamellae both lateral and posterior margins in mesial inner areas (e.g., Figures 12B, 60E and Supplementary Figure S2B, vlmtc: 100-3); tarsi 5-5-5; abdomen with six visible sternites; intersegmental membranes without ‘brick-wall’ pattern (Figure 12C: 107-0); tergite VIII and sternite VIII usually with sexual dimorphisms, frequently modified into lobes (e.g., Figures 12E, 19C, 31, 32, 47B and 61B,C: 116-1, 117-3, 135-3, 135-5, 137-3); tergite IX in male without ventral struts, basally ventrally fused (e.g., Figure 61E: 119-1), except Deropini; male aedeagus with simple and glabrous parameres very closely appressed to median lobe, parameres not widely separated from each other (e.g., Figures 12F, 20B,C, 33E–H and 56A–D: 142-1, 143-1, 143-2, 143-3); gonocoxites with small gonocoxite II and large gonostylus (e.g., Figures 20D and 56E: 154-0, 156-2), bearing curved setae (e.g., Figures 47D and 56E: 155-1). Modified after Newton et al. [16].

Description: Body (Figures 6A–D,F, 13A,B, 14, 21, 22, 35C,D, 36C–E, 40C–E, 43, 48, 49 and 57) minute to medium-sized, sub-limuloid, or rarely of a different unique form (Derops; Figure 43). Head (e.g., Figure 7A, Figure 8B, Figures 23A, 44A and 50) clearly smaller than pronotum, as long as wide to transverse, usually lacking ocular seta (sensu Campbell [42]) near base of eye on dorsal surface (Figure 16A: 6-0), except some Tachinusini (Figure 50: 6-1); frontal suture and midcranial suture present in most taxa (e.g., Figures 7A and 50, mcs: 11-1); tempora or postocular areas without neck constriction (e.g., Figure 9A and Figure 16A: 12-0), but occasionally with neck-like narrowing (e.g., Figures 26A, 45A and 51B,D: 12-1, 12-3); ventral side lacking longitudinal basolateral ridges along eyes (e.g., Figure 26A: 13-0), except in a few examples (e.g., Leucotachinus, Nepaliodes; Figures 53A and 58D: 13-1). Dorsal tentorial arms (e.g., Figures 9A and 16A: 18-0) developed, reaching to inner surface of head capsule and forming tentorial pits in most taxa. Hypostomal sutures (e.g., Figure 10E, Figures 16B and 53A: 14-0) fully separated, each curved or angulate. Gular sutures (e.g., Figures 10E, 16B and 53A: 15-0, 16-0, 16-1) widely separated, each rather short, usually more or less curved. Antennal insertion (e.g., Figures 7A, 15A, 26G, 44A and 50) located at, or anterior to, anterior margin of eyes in most taxa (e.g., Figures 44A and 50B: 10-0), usually partially concealed by frontal shelf (e.g., Figure 50B: 8-0, 9-0). Antenna (e.g., Figures 7A–C, 9C,D, 23, 37A and 41B) usually filiform to moniliform (e.g., Figure 15A: 19-0) to clavate or clubbed apically (Figure 23B: 19-3), rarely modified (e.g., Figure 26G: 19-2), not verticillate, frequently with clear pattern of dense and fine recumbent pubescence (e.g., Figures 26D and 59C: 21-1, 21-3). Labrum (e.g., Figures 9B and 53H: 24-1, 25-1) with setose or spinose processes in middle and lateral areas along anterior margin in most cases. Mandible (Figures 9B and 16C) triangular to falciform, lacking subapical inner tooth (Figure 9B: 26-0, 27-0), with developed molar lobe (Figure 16C: 28-0). Maxillary palpus (e.g., Figures 10A–D, 16E, 27A–D, 45D, 53C,F and 59A) 4-segmented, moderately long; palpomere 1 shortest. Labial palpus (e.g., Figures 9E, 16F, 26B,E,F, 45B, 53B,D,E,G and 59B) 3-segmented, inconspicuous, except Euconosoma. Ligula (glossae) (e.g., Figures 9E, 45B and 53D,E,G) large, as long as wide to transverse, clearly extending beyond each labial palpus laterally (Figures 9E, 45B and 53E: 45-1). Pronotum (e.g., Figures 7A,B,D, 8A, 11A, 18A, 27E–G, 37B, 41D, 51 and 58A) usually broad, bell-shaped to transverse oval, widened toward base in most cases, but with few exceptions (e.g., Derops, Nepaliodes; Figures 44A and 58B,C: 49-1, 49-4). Pronotal hypomeron (Figure 11A, Figures 18B, 27F, 54G and 59D: 59-0) without transverse ridge at apical 1/3 to 1/4 (such ridge shown in Figure 69A,B: 59-1). Mesospiracular peritremes (e.g., Figures 18A, 27E–G and 52B, msp: 67-2) well sclerotized, except Leucotachinus. Scutellum (Figure 11E: 68-0) with prescutoscutellar suture (pss) (sensu Blackwelder [30]: Figure 4A,C) lying near base of scutellum. Elytron (e.g., Figures 7B,D, 8D, 11E, 15C, 30, 38A–C, 41E,F, 44C, 51C and 58A,C) short to relatively long, exposing most of abdomen; sutural edge not longitudinally raised (Figures 7D, 24D and 51A, C: 78-0); lateral side with epipleural ridge or keel (e.g., Figure 52C: 80-0), sometimes very strongly folded inward (Figure 30A,B: 81-3). Metendosternite (e.g., Figures 11B, 18D, 28G,I and 54H) Y-shaped, without median process (most, see Figure 28G: 92-0 vs. Figure 28I: 92-1) and posterolateral arms. Legs (e.g., Figures 7E, 12A, 14C,D,G, 15D, 21F, 22C, 28E, 29, 36C–E, 38E–G, 43, 44C, 48E and 52C) with 5-5-5 tarsal formula; protrochantin (e.g., Figure 45E, prtcn) well exposed; procoxae (e.g., Figures 12A, 24A–C, 29A, 45E and 52A) prominent, usually enlarged (e.g., Figures 12A, 24C and 29A: 96-3); mesocoxae (e.g., Figures 11C,D, 24A–C, 28A–D, 46A, 52B and 54C–F) narrowly separated in most taxa (Figures 24B, 28C, 46A and 54C,D,F: 87-0), rarely contiguous (some Vatesini and Leucotachinus; Figures 52A and 54E: 87-1); metacoxae contiguous (e.g., Figures 11C,D, 52B and 58D), with ventral lamellae in both lateral and posterior margins in mesial inner areas (e.g., Figure 12B, Figures 18E, 28E, 46B, 60E and Supplementary Figure S2B, vlmtc: 100-3), except Vatesus (Figure 28H, vlmtc: 100-0). Abdomen (e.g., Figures 7E, 15D, 25A,C and 44C) gradually to strongly tapering posteriorly, with six visible sterna; paratergites present (most), or absent (Euconosomatina stat. rev., sensu nov.; Figure 15D: 124-2), usually with only a single pair per segment on segments III–VII (Figures 7E and 44C: 124-0), but occasionally with two pairs (some Vatesini sensu nov.; Figure 39F, pts); intersegmental membranes without ‘brick-wall’ pattern (Figure 12C: 107-0); tergite VIII and sternite VIII sexually dimorphic, frequently with distinct apical lobes (e.g., Figures 12E, 19C, 31, 32, 39A,B,D,E, 42C,D, 44C, 47B, 55B–D and 61B,C: 116-1, 117-2, 117-3, 135-2, 135-3, 135-4, 135-5); female sternite VIII with row of sensory setae along lobes or in alternative positions on posterior margin (Figures 12D, 19D, 32A,B, 47E, 55D and 61C: 138-2, 138-3, 138-4). Male genital segments (abdominal segments IX and X): tergite IX (e.g., Figures 20A, 33A–D, 39C, 42E, 47F, 55E–G and 61E) dorsally contiguous or separated in basal half, ventrally basally fused except in Derops (see [23,43]), without ventral struts (see Figures 33D and 61E: 119-1). Male genitalia: aedeagus (Figures 12F, 20B,C, 33E–H, 47F, 56A–D and 61F) with parameres very closely appressed to median lobe (e.g., Figures 33E,G, 56C and 61F: 142-1); each paramere simple, the two not widely separated from each other (e.g., Figures 12F, 20B,C, 33F,H, 47F, 56A,B,D and 61F: 143-1, 143-2, 143-3), without parameral setae (e.g., Figure 12F: 147-0); internal sac usually without prominent spines (e.g., Figure 56A: 141-0), except Tachinoproporus (Figure 42B, dsp). Female genital segments (Figures 12G, 20E, 34, 39H, 47C and 61D: 139-0) usually transverse to only weakly elongate; basal area not usually well sclerotized (Figures 20E and 61D: 140-1). Female genitalia: gonocoxites (e.g., Figure 12G, 20E, 34, 39H, 47D, 56E and 61D) present, well-developed; gonocoxite II shorter than gonostylus in most taxa (e.g., Figures 20D, 47C,D: 154-0), usually covered with curved setae (e.g., Figures 20D, 34A,C, 47C,D and 56E: 155-1, 155-2); gonostylus (e.g., Figure 12G, 34, 47C,D and 56E: 156-2) large, conspicuous.

Composition: Four tribes of 36 genera (7 extinct), with 1194 species (18 extinct). See Table A1 for overview and distributions. See also Appendix A.

• Tribe Tachyporini MacLeay, 1825 [40] sensu nov.

  -

  Subtribe Tachyporina MacLeay, 1825 [40] stat. nov., sensu nov.

  -

  Subtribe Euconosomatina Cameron, 1918 [44] stat. rev., sensu nov.

• Tribe Vatesini Seevers, 1958 [13] sensu nov.
• Tribe Deropini Smetana, 1983 [23]
• Tribe Tachinusini Fleming, 1821 [45] stat. rev., sensu nov.

Fossils: Fossil records of Tachyporinae sensu nov. from both the Cenozoic and Mesozoic are relatively prevalent and even abundant, found mainly from the various Holarctic deposits ([46,47]; see details in each of the taxonomic category below). †Leehermania prorova Chatzimanolis et al., 2012, the Upper Triassic fossil species from the Cow Branch Formation of southern Virginia, USA, was described as the oldest Staphylinidae and the earliest representative of Polyphaga [48]. In the original description, it was suggested that there is a possible affinity with Tachyporinae, or its close relatives [48]. Contrary to doubts of the systematic position of the fossil outside of Staphylinidae [2], Chatzimanolis [47] again recognized †Leehermania as the oldest described staphylinoid beetle. Nevertheless, †Leehermania was recently moved to an extinct lineage within the small beetle suborder Myxophaga, closest to the modern family Hydroscaphidae, based on re-examination of the type material and rigorous phylogenetic analyses [49]. As there are no staphylinid fossils found from the Triassic deposits, the most reliable oldest fossil records of Tachyporinae sensu nov. date back to the Middle to Upper Jurassic based on compression fossils found in China, Kazakhstan, and Australia [49,50,51,52]. Most described tachyporine fossils are compressions, whereas only a handful of amber inclusions have been described so far (Table A1 and Table A2).

Notes on family-group names: The present study on Tachyporinae (in the current sense) resurrects a little-used family-group name based on Tachinus. The taxonomic treatment (Opinion 1743) is made by The International Commission on Zoological Nomenclature (ICZN) [53]. This opinion established the family-group name priority for names based on Tachyporus over those based on Tachinus and emended the stem of the family-group names based on Tachinus to Tachinus- instead of Tachin- because of the (senior) homonymy of the latter with the extremely widely used family name Tachinidae in Diptera (based on Tachina Meigen) [53]. It also added names to the Official Lists of names in zoology and designated type species that are relevant in some cases [53].

Remarks: A series of significant changes are made for the new definition of Tachyporinae sensu nov. and its tribal divisions (Figure 5). After my phylogenetic analyses and observations, the revised classification contains the four tribes as listed there. This means that the originally included tribe Mycetoporini is now excluded from Tachyporinae, and is raised to subfamily rank (see below and Discussion). Therefore, the former classification comprised of five tribes is rejected here. Although I could not examine most of the tachyporine fossils, they are putatively assigned to the newly defined tribes based on available information. Two extant tachyporine genera, namely Tachinoporus and Tachinoproporus, were unambiguously placed in Tachyporinae sensu nov. on the basis of my direct examination of the type material.

The revised classification also sheds light on their ecology and microhabitats. Although there is significant lack of ecological information for the tachyporine taxa used here, I speculate a possible ecological trend for Tachyporinae sensu nov. First, semi-aquatic taxa are found only in Deropini and Tachinusini stat. rev., sensu nov. (clade E in Figures 3 and 4), and at least some members seem to be adapted such environments. Second, social parasitism is only found in Tachyporini sensu nov. (myrmecophilous only: Lamprinodes Luze and Lamprinus Heer) and Vatesini sensu nov. (myrmecophilous: Vatesus; termitophilous: Termitoplus Silvestri). A possible termitophile, Sepedophilus nigeriensis (Silvestri, 1947), comb. nov. (= ‘Urolitus’ nigeriensis Silvestri, 1947 [54] (see Euconosomatina stat. rev., sensu nov. section below)), was probably incidentally collected from a termite nest, lacking any adaptive morphological features on the body based on the original description [54]. All other tachyporine genera have putatively free-living lifestyles.

3.2.2. Tribe Tachyporini MacLeay, 1825 sensu nov.

Tachyporini MacLeay, 1825: 49 [40] (Figures 1C, 2–20 and Figure S1; Table A1)

Type genus: Tachyporus Gravenhorst, 1802 [41]: 124.

Differential diagnosis: Tachyporini sensu nov. differs from all other tribes of Tachyporinae sensu nov. based on the following combination of characters: body pubescent with long and thin setae (at least elytra and abdomen), head without neck-like narrowing, antenna basally lacking clear borderline of dense and fine recumbent setae, maxillary palpomere 3 setose, longer and narrower than penultimate palpomere, and abdomen dorsally with blackish macrosetae.

Emended diagnosis. Body surface pubescent with long and thin setae (e.g., Figure 15B–D: 53-2, 74-2) (Tachyporina stat. nov., sensu nov. usually lacking setae on head and pronotum, but pubescent on elytra and abdomen; Figures 7B and 8D: 74-1, 74-2); head without neck-like narrowing (Figures 9A and 16A: 12-0); antenna without clear pattern (borderline) of dense and fine recumbent pubescence (Figures 9C,D and 17A: 21-0); maxillary palpomere 3 widest around middle (Figures 10A,B and 16E: 30-1) (widest at each apex in Lamprinus and Lamprinodes; Figure 10C,D: 30-0), not distinctly shorter than palpomere 2 (Figures 10A,B and 16E: 31-0, 32-1), with dense ground setae; maxillary palpomere 4 moderately to strongly pointed, widest at or near base, much shorter and narrower than penultimate palpomere (Figures 10C and 16E: 33-0, 34-0, 35-0); labial palpomere 3 more or less pointed, narrower than penultimate palpomere (Figures 9E and 16F: 40-0, 41-0), except Euconosoma Cameron; pronotum and elytra with (e.g., Figures 7A,B,D, 8A and 18F: 57-1, 75-1, 76-1, 77-1) or without (e.g., Figure 15C: 76-0, 77-0) arranged stout setae; abdomen strongly to very strongly tapering posteriorly; tergites III–VI with blackish macrosetae (e.g., Figures 7E, 15C: 109-1), each tergite not strongly transverse, width less than 2.5 times its length; tergite VIII and sternite VIII with more than several macrosetae (Figure 19C–E): 114-0, 133-0); male tergite VIII without modification, that of female with modification (Figures 12E and 19C: 117-3); male tergite IX contiguous dorsally in basal 1/3 (Figure 20A: 120-0), each apex elongate (Figure 20A: 122-1), with numerous macrosetae (Figure 20A: 123-0); male sternite VIII with posterior margin rather widely deeply emarginate medially (Figure 19E: 135-2); female sternite VIII without modification (Figure 19D: 137-0) or with only feebly developed projections (Figure 12D: 137-2).

Description: Body (Figure 6A–D,F, Figure 13A,B and Figure 14) small to relatively large for tachyporines, sub-limuloid to limuloid, with tapered abdomen; surface generally pubescent with long and thin setae, at least on elytra and abdomen (e.g., Figure 7B and Figure 15B,C: 4-2, 53-2, 74-2), but sometimes generally glabrous in head and pronotum (e.g., Figure 7A,C,D: 4-0, 53-0); punctation usually absent or inconspicuous (e.g., Figures 7A,C,D: 3-0, 51-0); color frequently bright, occasionally having markings or patterns on dorsum (e.g., Figures 6D,F and 14A,E). Head (Figures 7A–C, 8A,B, 9A and 15A,B and Figure 16A: 6-0) without ocular seta; postocular areas (e.g., Figures 9A, 16A: 12-0) without neck-like narrowing, but Symmixus with slight modification just behind eyes (Figure 8A: 12-2); postgena without minute setae. Antenna (Figures 6A–D,F, 7A–C, 8A–C, 9A,C,D, 13A,B, 14 and 15A and Figure 17A) short to moderate, filiform to fili-moniliform (Figure 9D: 19-0) [weakly modified in Lamprinodes (Figure 6A) and myrmecophilous form in Lamprinus (Figure 9C: 19-2)], without clear pattern (borderline) of dense and fine recumbent pubescence (e.g., Figures 9C,D and 17A: 21-0). Maxillary palpus (Figures 10A–D, 13D, 16E) somewhat small, palpomeres 2 and 3 usually pubescent (Figures 10A,B and 16E: 32-1); palpomere 3 widest around middle in most taxa (Figures 10A,B and 16E: 30-1) [except Lamprinodes (Figure 10C: 30-0) and Lamprinus (Figure 10D: 30-0)], not distinctly shorter than palpomere 2 (>0.7×; Figure 10A,B: 31-0); palpomere 4 moderately to strongly pointed, widest at or near base (Figure 10C: 33-0), clearly shorter and narrower than penultimate palpomere (Figures 10C and 16E: 34-0, 35-0). Maxillary lacinia with (Tachyporina stat. nov., sensu nov.) or without (Euconosomatina stat. rev., sensu nov.) unarticulated large, long spine; other numerous teeth and spines long, well-developed (Figures 10C and 16E: 38-0). Labial palpi (Figures 9E and 16F: 46-1) usually rather widely separated at base, slightly narrower, or subequal, to longest labial palpomere; palpomere 3 (Figures 9E and 16F) usually more or less pointed (except in Euconosoma, see Cameron [55]: Figure 2), widest at base (Figures 9E and 16F: 40-0), distinctly to moderately narrower than penultimate palpomere (Figures 9E and 16F: 41-0). Mentum strongly transverse, with truncate (Tachyporina stat. nov., sensu nov.) or broadly rounded (Euconosomatina stat. rev., sensu nov.) anterior margin. Pronotum (Figures 7A,B,D and 8A and Figure 18A,B) normal, bell-shaped, usually widest between base and basal 1/5 (Figures 7D and 15C: 50-0, 50-1), with (Tachyporina stat. nov., sensu nov.) or without (Euconosomatina stat. rev., sensu nov.) stout setae on dorsum; surface with (Euconosomatina stat. rev., sensu nov.) or without (most Tachyporina stat. nov., sensu nov.) ground microsetae; anterior margin weakly to moderately concave (Figures 7A and 18A: 55-1), with sharply pointed anterior angles (Figures 7A and 18A: 56-2). Pronotal hypomeron (Figures 8C, 11A, 14G and 18A–C) moderate to wide in basal third (Figures 11A and 18B: 60-1, 60-2), strongly inflexed, not visible in lateral view, with diverse structural patterns of postcoxal processes (Figures 11A and 18A,B: 61-2, 61-4, 61-5). Prosternum with sternacoxal ridge (tsr) moderately distant from (Tachyporina stat. nov., sensu nov.), or very close to (Euconosomatina stat. rev., sensu nov.) anterior margin of prosternum in medio-lateral areas, without developed prosternal process (Figure 18A: 64-0). Procoxal cavities open (Figure 11A: 66-0) or closed (Figure 18A: 66-1) posterolaterally (limited members of Euconosomatina stat. rev., sensu nov.). Elytron (Figures 6A–D,F, 7B,D, 8A,D,E, 11E, 13A, 14A–F, 15C and 18F) elongate, usually moderate length, pubescent, with or without macrosetae on dorsum; epipleural gutter along outer margin absent (Euconosomatina stat. rev., sensu nov.) or very narrow (most Tachyporina stat. nov., sensu nov.); lateral side with epipleural ridge or keel, which is moderately folded inward (e.g., Figure 18F: 81-1). Mesoventrite with (Euconosomatina stat. rev., sensu nov., except Euconosoma) or without (Tachyporina stat. nov., sensu nov.) longitudinal median carina. Metendosternite (Figures 11B and 18D: 90-2) with anterior arms thick, frequently lamellate. Legs (Figures 6A,F, 7E, 8C, 11C,D, 12A,B, 13E, 14A–D,G, 15A,D, 17B–D and 18E and Figure 19A) moderately long to long (see Figure 14C,D); procoxae (e.g., Figures 8C, 12A and 14C,G) expanded, large (distinctly expanded in Lamprinus; Figure 12A: 96-3); tibial apices with (Euconosomatina stat. rev., sensu nov.) or without (Tachyporina stat. nov., sensu nov.) ctenidium of evenly arranged dense equal length spines with much larger apical spur; metacoxae (Figures 11C,D and 18E: 98-1) medium size in each lateral half; metatibiae with short spurs at apex, shorter than 2/5 of metatarsomere 1 (Figure 17D: 101-0), except Lamprinus; metatarsus long to markedly long, more than half length of metatibia (Tachyporina stat. nov., sensu nov.), or even longer (Euconosomatina stat. rev., sensu nov.). Abdomen (Figures 6A–D,F, 7E, 8E, 12C, 13A,B 14 and 15D) strongly to very strongly tapering from base to apex, with single pair of paratergites (Tachyporina stat. nov., sensu nov.), or without paratergites (Euconosomatina stat. rev., sensu nov.), on segments IV–VII. Tergites III–VI with macrosetae on posterolateral edges (e.g., Figures 7E, 15C: 109-1), each tergite moderately transverse. Tergite VIII (Figures 12E and 19C: 114-0) with several or more macrosetae; posterior margin in male without modification (116-0), that of female (Figures 12E and 19C: 117-3) with simplified lobes. Male tergite IX (Figure 20A: 119-0, 120-0, 121-0, 122-1, 123-0) fused at base of ventral side, not divided by sternite IX; dorsal side contiguous in basal 1/3 to 2/3 (Figures 20A: 120-0, 121-0), then abruptly divided apically, each with elongate apex (Figure 20A: 122-1); apical areas each with more than several macrosetae, not restricted to apices (Figure 20A: 123-0). Sternite III with (Euconosomatina stat. rev., sensu nov.) or without (Tachyporina stat. nov., sensu nov.) longitudinal median carina. Male sternite VII lacking characteristically arranged peg-like setae. Sternite VIII (Figures 12D and 19D,E: 133-0) with numerous distinct macrosetae; posterior margin in male (Figure 19E: 135-2, 136-0) rather widely deeply emarginate medially without lobes, that of female unmodified (Euconosomatina stat. rev., sensu nov.), or with a pair of feebly developed projections (most Tachyporina stat. nov., sensu nov.), each apex with row of sensory setae along these projections or alternate positions in female (Figures 12D and 19D: 138-2). Male aedeagus (Figures 12F and 20B,C) narrowly elongate, slender, not curved or arcuate in lateral view; parameres in apical part longitudinally contiguous or only weakly separated from each other (Figures 12F and 20B,C: 143-2, 143-3), not widely longitudinally flattened or plate-like (e.g., Figures 12F and 20B: 145-0). Female genitalia (Figures 12G and 20D,E) with gonocoxite II slender, narrowly elongate (Figures 20E: 153-0), bearing only curved setae (Figures 12G and 20D: 155-1).

Composition: Two subtribes, 8 genera (1 extinct), with 510 species (6 extinct). See Table A1 for overview and distributions.

• Subtribe Tachyporina MacLeay, 1825 [40] stat. nov., sensu nov.
• Subtribe Euconosomatina Cameron, 1918 [44] stat. rev., sensu nov.

Remarks: The newly defined tribe Tachyporini sensu nov. contains only the core-members of the tribe, namely the Tachyporus-related and Sepedophilus-related genera, with a newly established subtribal division as above. This led to the exclusion of many genera previously treated as ‘Tachyporini’, such as Coproporus and Tachinus. Based on the results of the phylogenetic analyses, Tachyporini sensu nov. forms a sister group to the rest of Tachyporinae sensu nov.

3.2.3. Subtribe Tachyporina MacLeay, 1825 stat. nov., sensu nov.

Tachyporina MacLeay, 1825: 49 [40] (Figures 2–13; Table A1)

Type genus: Tachyporus Gravenhorst, 1802 [41]: 124 (= †Mesotachyporus Gusarov, 2000 [56]: 256 syn. nov.).

Differential diagnosis: Tachyporina stat. nov., sensu nov. differs from members of Euconosomatina stat. rev., sensu nov. based on the following combination of characters: head and pronotum glabrous (sparsely and inconspicuous, if present), pronotum with arranged macrosetae, protibia without longitudinal row of close-spaced spines along outer margin, metatarsus clearly shorter than whole length of metatibia, and abdomen with single pair of paratergites.

Emended diagnosis: Body rather less convex above in cross section (e.g., Figure 6A,D,F), with usually moderate-width pronotal hypomera (Figure 11A: 60-1); surface somewhat glossy, typically glabrous on head and pronotum (e.g., Figure 7A,C,D: 4-0, 53-0); color usually bright, at least on elytra for many taxa (e.g., Figure 6A,B,D,F); gular sutures not distinctly divergent in basal-most areas (Figure 10E: 16-0); maxillary lacinia with unarticulated large, long spine at apex (e.g., Figure 10C: 37-1); mentum with anterior margin more or less linear; pronotum with characteristically arranged macrosetae (e.g., Figures 7A and 11A: 57-1); prosternum with sternacoxal ridge (tsr) moderately distant from anterior margin of prosternum, without prominent modification of furcasternum (Figure 11A: 63-0); protibia without longitudinal row of close-spaced spines along outer margin (e.g., Figure 12A: 97-0); procoxal cavities always open behind (Figure 11A: 66-0); elytron usually with very narrow epipleural gutter along outer margin (Figure 7D: 79-1) (but absent in Palporus; Figure 7: 79-0), bearing arranged macrosetae on surface in most taxa (e.g., Figures 7B,D, 8A and 11E: 75-1, 76-1, 77-1); mesoventrite without longitudinal median carina (Figure 11D: 85-0); metatarsus long, more than half length of metatibia, but shorter than whole length of metatibia (e.g., Figure 7E: 103-0); abdomen with a single pair of paratergites on segments III–VII (e.g., Figure 7E: 124-0); sternite III without longitudinal median carina (e.g., Figure 12C: 125-0); female sternite VIII frequently with a pair of feebly developed projections along posterior margin (Figure 12D: 137-2); sclerotized spermatheca absent.

Composition: Five genera, with 144 species (4 extinct). See Table A1 for overview and distributions.

• Lamprinodes Luze, 1901 [57]: 181.
  Type species: Tachyporus saginatus Gravenhorst, 1806 [58]: 6.
• Lamprinus Heer, 1839 [59]: 286.
  Type species: Lamprinus lasserrei Heer, 1839 [59]: 286 (= Oxyporus erythropterus Panzer, 1796 [60]: pl. 21).
• Palporus Campbell, 1979 [61]: 11 stat. nov.
  Type species: Staphylinus nitidulus Fabricius, 1781 [62]: 337.
• Symmixus Bernhauer, 1915 [63]: 56.
  Type species: Symmixus sikkimensis Bernhauer, 1915 [63]: 57.
• Tachyporus Gravenhorst, 1802 [41] sensu nov. (= †Mesotachyporus Gusarov, 2000 [56]: 256 syn. nov.).
  Type species: Staphylinus chrysomelinus Linnaeus, 1758 [38]: 423.

Fossils: Similar to the abovementioned situation of Sepedophilus, the fossils of Tachyporus sensu nov. are also diverse and abundant in mid-Eocene Baltic amber ([64,65]; Yamamoto, pers. obs.), but with only a single described species, Tachyporus bicoloratus Paśnik, 2005 [66]. The only extinct genus †Mesotachyporus has been known from the Mesozoic [56], but it is here synonymized under Tachyporus (see discussion below). From the Cenozoic, †Tachyporus annosus Herman, 2001 [67] (= †T. nigripennis Scudder, 1900) [68] is known from the Eocene Florissant deposit in Colorado, USA [21]. Additionally, there is a Tachyporus fossil found from early Middle Miocene Dominican amber [69], but it has not yet been described.

Remarks. This newly defined subtribe contains the type genus of Tachyporinae sensu. nov., namely Tachyporus sensu nov. Compared to the subtribe Euconosomatina stat. rev., sensu nov., the members of Tachyporina stat. nov., sensu nov. share the conserved body plan including the presence of paratergites, and all species lack the comb-like spines on the protibiae.

The tachyporine monobasic tribe Symmixini Bernhauer, 1915 [61] had been recognized until rather recently [21], but this tribe was synonymized under Tachyporini by Schülke [22]. In this study, I have examined the type genus Symmixus, specifically the holotype of the type species (Figures 6D,E and 8), and found that it is indeed very close to Tachyporus sensu nov. in many aspects, although Symmixus has the characteristically modified metatarsomere 3 [22]. In light of this conclusion and the phylogenetic results, the synonymy of Symmixini is maintained here and I have placed it in this subtribe.

3.2.4. Genus Tachyporus Gravenhorst, 1802 sensu nov.

Tachyporus Gravenhorst, 1802: 124 [41] (Figures 2–4, 6F, 7A,E, 9A,B,D, 10A,E, 11B, 13 and Figure S1B,D; Table A1)

= †Mesotachyporus Gusarov, 2000 [56]: 256 syn. nov.

Type species: Staphylinus chrysomelinus Linnaeus, 1758 [38]: 423.

Diagnosis: See Campbell [61], as subgenus Tachyporus.

Remarks: Previously, the genus Tachyporus included two subgenera, Tachyporus sensu str. and Palporus Campbell [21,61,70]. In this study, I have recognized only Tachyporus sensu str. as members of the newly defined genus Tachyporus sensu. nov. Palporus is raised to a distinct genus based on observation of morphological characters and their phylogenetic analyses (see below).

The extinct monotypic genus †Mesotachyporus from Upper Cretaceous (Turonian) New Jersey amber can undoubtedly be assigned to this subtribe on the basis of general morphological similarity with Tachyporus in the traditional sense, namely the overall body shape, short and slender maxillary palpomere 4, antennal pubescence, general shape of the pronotum, and chaetotaxy of the elytra (Figure 13A,B,D,E; [56]; see also a habitus photograph in Grimaldi et al. [71]: Figure 8A). During the course of my study, I re-examined the holotype of †Mesotachyporus puer Gusarov, 2000 [56] to unveil the generic identity and to extract more characters for the genus and species. As a result, the only notable difference between †Mesotachyporus and Tachyporus is the presence of markedly shortened first tarsomeres in †Mesotachyporus, compared to recent Tachyporus species, as already mentioned in the original description [56]. However, this character alone is not enough to justify the generic validity. Similarly, a fossil species of megalopsidiine rove beetle in mid-Cretaceous Kachin amber (the Albian–Cenomanian boundary or older) from northern Myanmar, which also has similarly reduced first tarsomeres compared with the modern congeners, was placed in the extant genus Megalopinus Eichelbaum, rather than creating a new genus [72]. Here, †Mesotachyporus syn. nov. is not maintained at generic rank, but is synonymized under Tachyporus sensu nov. The new combination, †Tachyporus puer (Gusarov, 2000) [56] comb. nov., is established here. This fossil species may represent another example of bradytely, showing long-term morphological stasis of an organismal lineage over deep evolutionary time [73]. This phenomenon has frequently been found in beetles, particularly Staphylinoidea, in Kachin amber (e.g., [74,75,76,77]), and Clarke & Chatzimanolis [74] suggested that the continuous presence of mesic habitats over geological time had contributed to such morphological stability. As Chatzimanolis [47] noted, studies assessing the background of this phenomenon based on statistical evidence will be desired. On the other hand, there are some staphylinid taxa known from Kachin amber with unusual morphological features compared to Recent relatives [78,79,80,81]. Further discovery may reveal morphological diversity and evolution in the Mesozoic.

3.2.5. Genus Palporus Campbell, 1979 stat nov.

Palporus Campbell, 1979: 11 [61] (Figures 3, 4, 6C, 7B, 10B, 11A,C,E, 12F and Supplementary Figure S1A,C; Table A1)

Type species: Staphylinus nitidulus Fabricius, 1781 [62]: 337.

Diagnosis: See Campbell [61].

Composition: Two species, as listed below.

• nitidulus (Fabricius, 1781 [62]: 337), comb. nov. (Staphylinus). Distribution: Palaearctic, Oriental, and Afrotropical Regions; intro. Nearctic and Australian Regions.
  * See Herman [21] and Schülke & Smetana [70] for synonymic information.
• neomexicanus (Campbell, 1979 [61]: 14), comb. nov. (Tachyporus). Distribution: USA (New Mexico, Colorado).

Remarks: The subgenus Palporus Campbell was established for the two Tachyporus species in a study of the North American Tachyporus [61]. Since the original description, no additional species have been included in Palporus. This subgenus was characterized by the following combination of characters [61]: body small (less than 1.4 mm), slender; elytra narrower, parallel-sided, and; maxillary palpus with palpomere 4 short and thick, etc.

As a result of the phylogenetic analyses (Figures 3 and 4), Palporus, i.e., Palporus nitidulus comb. nov. (= Tachyporus nitidulus; Figures 6C, 7B, 10B, 11A,E,C 12F, and Supplementary Figure S1A,C), was separated from the Tachyporus clade, which is comprised of three species of Tachyporus sensu str., including the type species of Tachyporus, namely Tachyporus chrysomelinus (Figures 6F and 12B). The internal generic relationship within Tachyporina stat. nov., sensu nov. was not statistically supported by the lower bootstrap values (Figure 3), resulting in weak evidence for the generic status of Palporus. However, several morphological evidences probably justify this new generic validity.

As mentioned above, Palporus can be separated from Tachyporus sensu str. by the general body form in having smaller and more slender body [61], with more or less parallel-sided elytra which widest in middle (Figure 7B: 69-1). In Tachyporina stat. nov., sensu nov., the typical members have basally widened pronotum, with the maximum width situated at, or near, the base in most taxa (except Symmixus). In contrast, Palporus species have distinct pronotum in comparison with three genera (Tachyporus, Lamprinus, and Lamprinodes), with the maximum width located between the basal 1/4 and middle of the pronotum (Figure 7B: 50-3). These three genera have posteriorly broadened pronotum widest at or near base (Figure 7D: 50-1), whereas the widest point of the pronotum in Symmixus is located between basal 1/5 and basal 1/4 (Figure 8A: 50-2). Moreover, Symmixus can be discriminated from Palporus by having more elongate elytron (ratio of length/width: >1.8×; Figures 6D and 8D: 70-0), and Palporus has shorter and less elongate elytron (length/width: 1.3–1.8×; Figures 6C and 7B: 70-1). Another distinct feature is the structures of the maxillary palpi (Figures 10B and Supplementary Figure S1A). The maxillary palpomere 3 of Palporus is very thick and strongly expanded, but the remaining other Tachyporina stat. nov., sensu nov. genera do not have such structure. In Lamprinus and Lamprinodes, the maxillary palpomere 3 is gradually widened apically and widest at (or near) the apex (Figures 10C, D: 30-0). On the other hand, Tachyporus and Symmixus has weakly expanded maxillary palpomere 3, with the widest point located around middle of the palpomere (Figures 10A and Supplementary Figure S1B: 30-1). The density of ground setation on maxillary palpomere 3 is also clearly different. In Palporus, it is much more densely covered with setae than in the other genera. The maxillary palpomere 4 is also distinctive in Palporus; it is very short and thick, clearly broader than that of the rest of Tachyporina stat. nov., sensu nov. (Figure 10B and Supplementary Figure S1B). Furthermore, this palpomere is unusual in Palporus as it is abruptly narrower in apical third (Supplementary Figure S1B, arrow), and it is prominently densely pubescent ([61]: Figure 84) (see also Figure S1A). I found another characteristic feature in the female genitalia of Palporus. The gonostylus in Palporus is much longer than gonocoxite II (Supplementary Figure S1C), but it is only slightly to moderately longer, or even shorter, than gonocoxite II in the other members of Tachyporina stat. nov., sensu nov. (Figure 12G and Supplementary Figure S1D). Finally, Palporus is the unique taxon which completely lacks epipleural gutter along the outer margin of elytron in Tachyporina stat. nov., sensu nov. (Figure 7B: 79-0).

In light of morphological characters and their phylogenetic analyses, these subgenera should be considered as separate genera, i.e., Tachyporus sensu nov. and Palporus stat. nov.

3.2.6. Subtribe Euconosomatina Cameron, 1918 stat. rev., sensu nov.

Euconosomatina Cameron, 1918: 216 [44] (Figures 1C, 2–5 and 14–20; Table A1)

Type genus: Euconosoma Cameron, 1918 [44]: 215.

Differential diagnosis: Euconosomatina stat. rev., sensu nov. differs from members of Tachyporina stat. nov., sensu nov. based on the following combination of characters: head and pronotum densely pubescent with silky fine setae, pronotum without arranged macrosetae, protibia with longitudinal row of close-spaced spines along outer margin, metatarsus very long, much longer than whole length of metatibia, and abdomen without paratergites.

Emended diagnosis: Body rather strongly convex above in cross section (e.g., Figures 14D,F and 15B), with wide pronotal hypomera (Figure 18B: 60-2); surface less glossy, uniformly densely pubescent including head and pronotum with silky fine setae (e.g., Figure 15B–D: 4-2, 53-2, 74-2); color usually black to dark reddish brown (Figure 14), sometimes with colorful spots or maculations (Figures 14A,E and 15C); gular sutures strongly divergent sides, nearly transverse, in basal 1/4 (Figure 16B: 16-1); maxillary lacinia without unarticulated large, long spine at apex (e.g., Figure 16E: 37-0); labium with ligula sometimes with medial premental lobes and large, peg-like setae (Figure 16F: 44-3); mentum with anterior margin broadly rounded (Figure 16B: 47-2); pronotum widest at base, densely pubescent, lacking arranged stout setae (e.g., Figure 15B,C: 50-0, 53-2, 57-0); prosternum with sternacoxal ridge (tsr) very close to anterior margin of prosternum (Figure 18C: 63-1), with frequently modified furcasternum (Figure 18A: 65-1); protibia with longitudinal row of close-spaced spines along outer margin (Figure 17B,C: 97-1), except †Palaeosepedophilus [82]; protarsi with basal three tarsomeres expanded (Figures 15A and 17C); meso- and metatibial apices bordered by ctenidium of evenly arranged dense equal length spines with much larger apical spur (Figures 15D, 17D); procoxal cavities occasionally closed behind (e.g., Figure 18A: 66-1); elytron without epipleural gutter along outer margin (Figure 15C: 79-0), lacking arranged stout setae in most taxa as in Figure 15C, D (except the Sepedophilus scriptus species group; Figure 18F: 76-1, 77-1); mesoventrite with longitudinal median carina (Figure 19A: 85-1), except Euconosoma; metatarsus very long, much longer than whole length of metatibia (e.g., Figure 15D: 103-1); abdomen without paratergites, with only sutures (Figure 15D: 124-2); sternite III with longitudinal median carina (Figure 19B: 125-1); female sternite VIII with posterior margin unmodified, lacking a pair of feebly developed projections (Figure 19D: 137-0); spermatheca sclerotized, simple.

Composition: Three genera (1 extinct), with 366 species (2 extinct). See Table A1 for overview and distributions.

• Euconosoma Cameron, 1918 [44]: 215.
  Type species: Euconosoma elegans Cameron, 1918 [44]: 216 (= Conosoma pictum Bernhauer, 1903 [83]: 25).
• Sepedophilus Gistel, 1856 [84]: 386 (= Urolitus Silvestri, 1947 [54]: 147 syn. nov.).
  Type species: Staphylinus pubescens Paykull, 1790 [85]: 138 (= Staphylinus littoreus Linnaeus, 1758 [38]: 422).
• †Palaeosepedophilus Paśnik & Kubisz, 2002 [82]: 357.
  Type species: †Palaeosepedophilus succinicus Paśnik & Kubisz, 2002 [82]: 357.

Fossils: It is noteworthy that the fossils of Sepedophilus in mid-Eocene Baltic amber are very diverse and abundant (Yamamoto, pers. obs.), although only one species, Sepedophilus balticus, has been formally described from this deposit [82]. Additionally, I have seen a single Sepedophilus fossil in early Middle Miocene Dominican amber deposited in the FMNH. As a newly defined subtribe Euconosomatina stat. rev., sensu nov. includes one extinct genus, †Palaeosepedophilus from Baltic amber [82], which can be placed in Euconosomatina stat. rev., sensu nov. by the general characters including the absence of the paratergites [82]. However, †Palaeosepedophilus is morphologically very distinct in lacking the rows of spines along the outer margin of protibiae and has ventro-dorsally compressed, axe-shaped terminal maxillary palpomeres [82].

Notes on family-group name: The name Euconosomini had been considered incorrect original stem formation, therefore I herein adopt the tribe-level name Euconosomatini Cameron, 1918 [44] established on the genus Euconosoma Cameron, 1918 [44] (stem: Euconosomat-) [20]. The family-group name Euconosomatini (= Euconosomini) originally contained a single genus Euconosoma only [44], but I also included Sepedophilus and †Palaeosepedophilus in Euconosomatina stat. rev., sensu nov. based on general similarities including the lack of abdominal paratergites, presence of a row of comb-like protibial spines (not in †Palaeosepedophilus [82]), and densely pubescent body. The name Sepedophilini Ádám, 2001 [86] is a subjective junior synonym of this name that never came into common use (Sepedophilini was synonymized under Tachyporini by Bouchard et al. [20]).

Remarks: In the present study, three genera of Tachyporini sensu nov. were grouped together to form a newly resurrected and defined subtribe Euconosomatina stat. rev., sensu nov. It can be easily recognized by the above-mentioned characters, especially the presence of the longitudinal row of close-spaced spines along the outer margin of the protibia (Figure 17B,C). Another remarkable feature in this subtribe is the absence of the abdominal paratergites (Figures 14D and 15D). Differing from most Osoriinae (except Eleusinini), the Staphylininae genus Coomania Cameron [87], or the Paederinae subtribe Procirrina (Pinophilini) have the same kind of fusion, the abdominal tergites and sternites are not fused together, i.e., ring-like, but are separated by a narrow suture along each lateral side.

The enigmatic monotypic genus Urolitus shares the same basic body plan with Sepedophilus, including the spines along outer margins of the protibiae and the absence of paratergites [54]. Other characters such as mouthparts and sternite VIII are nearly fully congruent with this genus. Therefore, Urolitus syn. nov. should be a junior synonym of Sepedophilus based on morphological similarity and the results of my phylogenetic analyses. Following this treatment, a new combination of the type species is provided: Sepedophilus nigeriensis (Silvestri, 1947) [54] comb. nov. Based on the presence of a row of macrosetae along the outer margin of the elytron [54], it may be close to the scriptus or similar undescribed species group (sensu Campbell [88]).

Campbell [88] divided Sepedophilus into 12 species groups based primarily on the North American species. Known larvae of these species groups have been the focus of interesting evolutionary research on feeding habits and strategies, as the larval types are generally associated with species groups and are also relevant to predaceous and mycophagous feeding habits [17,18]. Since the presence of so many undescribed Sepedophilus species and species groups have been suggested (e.g., [89,90,91]), more new species will undoubtedly be discovered in the future.

3.2.7. Tribe Vatesini Seevers, 1958 sensu nov.

Vatesini Seevers, 1958: 183 [13] (Figures 1A,B, 2–5 and Figure 21, Figure 22, Figure 23, Figure 24, Figure 25, Figure 26, Figure 27, Figure 28, Figure 29, Figure 30, Figure 31, Figure 32, Figure 33, Figure 34, Figure 35, Figure 36, Figure 37, Figure 38, Figure 39, Figure 40, Figure 41 and Figure 42; Table A1)

Type genus: Vatesus Sharp, 1876 [92]: 201.

Differential diagnosis: Vatesini sensu nov. differs from all other tribes of Tachyporinae sensu nov. based on the following combination of characters: forebody usually glabrous and strongly glossy, antenna short in most taxa, usually shorter than pronotal width, devoid of dense and fine recumbent pubescence in basal three or four antennomeres in most taxa, maxillary palpomere 4 longer than penultimate palpomere, pronotal hypomeron with very short postcoxal process, elytra usually shorter and less elongate, with strongly to distinctly folded elytral epipleuron, and abdomen rather strongly to very strongly tapering posteriorly, lacking blackish macrosetae dorsally.

Emended diagnosis: Forebody with surface glabrous (e.g., Figures 22A,B and 24D: 53-0, 74-0), rarely with inconspicuous microsetae, very strongly glossy (matte in Tachinoproporus; Figure 41D,E); head with (Figure 26A: 12-1) or without (Figure 23A: 12-0) very weak neck-like narrowing behind eyes; antenna short in most taxa, usually shorter than pronotal width (e.g., Figure 23B: 20-1), devoid of dense and fine recumbent pubescence in basal two or four antennomeres (Figure 26D: 21-1); maxillary palpomere 4 more or less pointed, widest at or near base, longer and narrower than penultimate palpomere (Figure 27A,C,D: 33-0, 34-2, 35-0) (shorter or subequal in Vatesus and Mimocyptus; Figure 27C: 34-0); pronotal hypomeron with weakly developed postcoxal process (e.g., Figure 27E: 61-1); elytra short in most taxa, with blade-like lateral and posterior margins (Figure 30: 70-2, 82-1); elytral epipleuron strongly to distinctly sharply inflexed (Figure 30A,B: 81-3); procoxa markedly large, strongly expanded (e.g., Figures 24B,C and 29A: 96-3); abdomen rather strongly to very strongly tapering posteriorly, lacking blackish macrosetae dorsally (except abdominal terminalia), except Tachinoporus and Vatesus berghoffae Kistner, 2006, which have scattered erect macrosetae on the abdominal tergites; abdominal segments III–VII with one (Figure 25A: 124-0) or two pairs of paratergites (Figure 39F, pts); abdominal segments IV–VI frequently with somewhat produced posterolateral margins (Figures 25A,B and 28F: 106-1); tergite VIII in both sexes usually with lobe-like modifications (Figure 31: 116-1, 117-3); male tergite IX abruptly divergent and separated dorsally in basal 1/3 in most taxa (Figure 33A: 120-1), each apex usually forming single lobe (Figure 33B,C: 122-2), usually with only single to several macrosetae (Figure 33C: 123-2), except few genera; male sternite VIII usually widely emarginate with developed lobes (Figure 32E: 135-4), that of female with longer lobes, bearing two or three sensory setae at apex (Figure 32A,B: 137-3, 138-3); male aedeagus usually slender, arcuate in lateral view in most taxa (Figure 33E–G); gonocoxite II triangular or narrowly elongate, with both normal and curved setae (Figure 34A,C: 153-1, 153-2, 155-2).

Description: Body (Figures 21, 22, 35C,D, 36C–E and 40C–E) minute to large for tachyporines, sub-limuloid to streamlined, rather strongly to markedly convex above in cross section; forebody strongly glossy (Figures 21A–E,G,H and 22A,B) (with large micro-reticulation resulting in matte dorsum in Tachinoproporus; Figure 41D,E), generally glabrous (e.g., Figures 24D and 30A: 53-0, 74-0), occasionally covered with inconspicuous microsetae (Figure 25A: 74-1), without distinct punctation (e.g., Figures 23B and 24D: 3-0, 73-0). Head (Figures 23, 24A–C, 26A, 37B,D and 41A) with eyes incorporated into head capsule, lacking vertexal ocular seta; postocular areas with very weak neck-like narrowing, just behind of eyes in derived taxa (Figure 26A: 12-1), but sometimes absent (Figure 23A: 12-0). Antenna (e.g., Figures 23, 26D,G, 37A and 41B) usually short to very short, shorter than pronotal width or even shorter than head width in many taxa (e.g., Figures 22B, C and 23B: 20-1), but longer in earliest diverging lineages (e.g., Figure 21A, B); structure diverse, fili-moniliform to clubbed (e.g., Figures 26D, 37A and 41B), or myrmecophilous form (Vatesus; Figure 26G: 19-2), usually with clear patterns of dense and fine recumbent pubescence (except Mimocyptus), i.e., lacking such setae on basal three or four antennomeres (Figure 26D: 21-1). Maxillary palpus (Figures 27A–D, 37C and 41C) elongate, usually generally lacking ground setae, except for limited macrosetae (Figure 27A: 32-2), but with some exceptions (i.e., Vatesus, Mimocyptus; Figure 27C: 32-1); palpomere 3 widest at or near apex (Figures 27C: 30-0); palpomere 4 more or less pointed, widest at or near base (Figure 27A: 33-0), longer than penultimate palpomere in most taxa (Figure 27A,D: 34-2) (except in Vatesus and Mimocyptus; Figure 27C: 34-0). Maxillary lacinia (Figures 27A–D, 37C and 41C) without unarticulated large, long spine (Figure 27B: 37-0), with numerous short teeth or spines in most taxa (Figure 27B: 38-1), except in Mimocyptus. Labial palpi (Figure 26B,E,F: 46-1, 46-2) generally widely or relatively widely separated at base; palpomere 2 strongly to markedly transverse in crown genera (Figure 26E,F: 39-1), but elongate in Cilea and Vatesus (Figure 26B: 39-0); palpomere 3 elongate, usually widest at middle or near base, but not at base (Figure 26B, F: 40-1), with inconspicuous pores in many examples (Figure 26B: 43-1), outer margin usually with a few to several thick, short peg-like spines (Figure 26E: 42-1). Mentum (Figure 26F: 47-2, 48-0) weakly to moderately transverse, with truncate or rounded anterior margin. Pronotum (Figures 22A,B, 23B, 24, 27E–G, 37B and 41D) normal, more or less bell-shaped, without macrosetae on dorsum (except Tachinoporus; Figure 37B); anterior margin usually weakly to moderately concave, usually with angulate anterior angles (e.g., Figure 27G: 56-1); posterior margin in few taxa with conspicuous clusters of blackish pores (cf. Figure 54G: 58-1), but absent in most taxa (Figure 27E–G: 58-0). Pronotal hypomeron (Figure 27E–G) wide in basal third (Figure 27G: 60-2), strongly inflexed, not visible in lateral view, with weakly developed, short and rounded postcoxal process (e.g., Figure 27E: 61-1). Prosternum (Figures 24A–C and 27E–G) with sternacoxal ridge (tsr) very close to anterior margin of prosternum in medio-lateral areas (Figure 27E: 63-1), without prosternal process. Elytron (Figures 21A–E,G,H, 22A,B, 24D, 30, 35C,D 36C,D, 38A–C, 40C–E and 41E, F) short in crown group such as Coproporus (length/width: <1.3×; Figure 30A, B: 70-2), but moderately long in earliest diverging genera such as Cilea, basically lacking macrosetae on dorsum (Figures 24D and 30A: 75-0, 76-0, 77-0) (except Tachinoporus; Figure 38A–C), but with very narrow to narrow epipleural gutter (Figure 24D: 79-2) along outer margin in most cases; lateral side with epipleural ridge or keel, which is strongly to very strongly folded inward (Figures 24A,B and 30: 81-2, 81-3), resulting in thin, blade-like lateral and posterior elytral margins (Figure 30: 82-1); posterolateral margin in Vatesus distinctly sinuate (Figure 30C: 83-2). Mesoventrite (Figures 24A–C and 28A–D) with (Figure 28B,C: 85-1, 85-2) or without (Figure 24B: 85-0) weakly raised longitudinal median carina, markedly developed, plate-like in Tachinoproporus (Figure 40E,F). Intermesocoxal process with depressed isthmus in derived genera such as Termitoplus (Figure 28A,B,D: 88-4, 88-5). Metendosternite (Figure 28G,I) with anterior arms thick and lamellate (Figure 28G: 90-2), but inconspicuous in Cilea. Legs (e.g., Figures 21A,F, 22C, 24A–C, 25C, 28A,E, 29, 35C,D, 36C–E, 38D–G, 40C–E and 41G–I) usually short, rarely moderate in length; structure normal in most taxa, but myrmecophilous form in Vatesus (Figure 29B,D: 93-1); procoxae (Figures 22C, 24A–C, 25C, 29A and 38E) distinctly developed, very large, much larger than profemora (Figures 24C, 29A: 96-3); metacoxae (Figures 24A,B and 28A,B,E) medium-sized in each lateral half (Figure 24A: 98-1); metatibia with long spurs at apex, clearly longer than 2/5 of metatarsomere 1 (Figure 29C: 101-1); metatarsus long, more than half length but shorter than whole length of metatibia (e.g., Figures 28E and 29B: 103-0). Abdomen (e.g., Figures 21, 22, 25, 36C,D and 40C–E) moderately to very strongly tapering from base to apex, lacking blackish macrosetae dorsally (except abdominal terminalia); posterolateral margins of visible basal four segments usually extending posteriorly (Figures 25A,B and 28F: 106-1); paratergites comprised of single pair on segments III–VII in crown group (124-0), but with two pairs in earliest diverging lineages (Figure 39F, pts). Tergites III–VII (Figure 25A: 109-0) without macrosetae (except Tachinoporus and Vatesus berghoffae; Figure 35C,D); each tergite usually strongly transverse, but seemingly much less transverse in Cileoporus (Figure 21B) and Tachinoporus (Figure 35C). Tergite VIII (Figures 31, 39A,D and 42C: 114-1) with only a few to several distinct macrosetae (Figure 31A: 114-1), except Vatesus (Figure 31B: 114-2); posterior margin in both sexes usually with lobes (Figure 31B: 116-1, 117-3). Male tergite IX (Figures 33A–D, 39C and 42E) fused at base of ventral side, not divided by sternite IX (Figure 33D: 119-1); dorsal side (Figures 33A–D and 42E) abruptly divided apically in basal 1/3 (Figure 33A: 120-1) (not in Mimocyptus; Figure 33C: 120-0), usually forming on each side a slender lobe with pointed apex (Figure 33B,C: 122-2) (two pairs each in Cilea; Figure 33A: 122-3), or less slender lobe, merely elongate in limited taxa (i.e., Cileoporus and Vatesus; Figure 33D: 122-1); apical areas each with at most several long macrosetae (123-2) (except Tachinoporus; Figure 39C), restricted to apices (except for Cileoporus). Sternite III without longitudinal median carina. Male sternite VII not emarginate or concave (except Cilea), lacking peg-like setae (Figure 25C: 131-0). Sternite VIII (Figures 32, 39B,E and 42D) with only a few to several distinct macrosetae (Figure 32A: 133-1), except Vatesus (Figure 32D: 133-2) and Tachinoporus (Figure 42D); posterior margin in male (Figures 32C–E, 39B and 42D) with diverse structures, usually widely emarginate with weakly developed lobes (Figure 32E: 135-4), that of female (Figures 32A,B, 39B and 42D) with developed lobes and associated smaller internal lobes (Figure 32A: 137-3), each apex in female with single pair or three sensory setae (Figure 32B: 138-3) (except Vatesus). Male aedeagus (Figures 33E–H and 42B) narrowly elongate, usually slender, moderately curved or arcuate in lateral view; parameres longitudinally contiguous (Figure 33F: 143-2) to moderately separated (Figure 33H: 143-1), not flattened or plate-like (Figure 33F: 145-0). Female genitalia (Figures 34 and 39H) with gonocoxite II usually more or less triangular (Figure 34A: 153-1), but narrowly elongate in ‘lower’ genera (Figures 34C and 39H: 153-2), bearing both normal and curved setae (Figure 34A,C: 155-2).

Composition: Ten genera (1 extinct), with 290 species (2 extinct). See Table A1 for overview and distributions.

• Cilea Jacquelin du Val, 1856 [93]: 25.
  Type species: Staphylinus silphoides Linnaeus, 1767 [94]: 684.
• Cileoporus Campbell, 1994 [91]: 126.
  Type species: Tachinus politus Bernhauer, 1923 [95]: 59.
• Coproporus Kraatz, 1857 [96]: 399.
  Type species: Coproporus colchicus Kraatz, 1858 [97]: cxc.
• Coprotachinus Cameron, 1933a [98]: 44.
  Type species: Tachinus congoensis Cameron, 1926 [99]: 283 (= Erchomus ampliatus Fauvel, 1905 [100]: 198).
• Mimocyptus Cameron, 1919 [101]: 241.
  Type species: Mimocyptus globulus Cameron, 1919 [101]: 241.
• Tachinoporus Cameron, 1928 [11]: 447.
  Type species: Tachinoporus basalis Cameron, 1928 [11]: 448.
• Tachinoproporus Cameron, 1928 [11]: 449.
  Type species: Tachinoproporus ferrugineus Cameron, 1928 [11]: 449.
• Termitoplus Silvestri, 1946 [12]: 547.
  Type species: Termitoplus grandis Silvestri, 1946 [12]: 551.
• Vatesus Sharp, 1876 [92]: 201.
  Type species: Vatesus latitans Sharp, 1876 [92]: 202.
• †Procileoporus Yamamoto, 2016 [46]: 165.
  Type species: †Procileoporus burmiticus Yamamoto, 2016 [46]: 167.

Fossils: The extinct monotypic genus †Procileoporus was established based on †P. burmiticus Yamamoto, 2016 from mid-Cretaceous Burmese amber from Kachin State, northern Myanmar [46]. This extinct species was described on the basis of a rather poorly preserved male adult, but I now have several well-preserved adult fossils of the same species for future comparative study (Yamamoto, in prep.). As discussed in Yamamoto [46], †Procileoporus generally resembles the four vatesine genera, i.e., Cilea, Cileoporus, Coproporus, and Coprotachinus. Among them, †Procileoporus is particularly similar to Cileoporus in having a slender body and elongate elytron, together with similar configurations of the abdominal tergite IX in the male [46]. For these reasons, this fossil genus is herein unambiguously assigned to Vatesini sensu nov.

So far, only a single fossil has been definitively assigned to the extant genus Coproporus, namely C. electron Yamamoto, 2016, from early Middle Miocene Dominican amber [102].

Remarks: Until now, the tribe Vatesini has been comprised of only the single myrmecophilous genus Vatesus, associated with army ants, from the Neotropical region. However, my phylogenetic analyses did not show at all that it was a tribe-level group. Certainly, Vatesus was fully resolved among the genera of the Coproporus-related group of Tachyporini. Consequently, the present study greatly expands the concept of the tribe, encompassing the ten genera listed above. A close relationship between Coproporus and Vatesus has independently been suggested by larval and adult morphologies, respectively [25,27]. In light of the previous studies and current results, a newly defined Vatesini sensu nov., including the Coproporus-related taxa, is one of the key solutions to resolve the polyphyly of Tachyporini in the old sense (see further in Discussion).

It is noteworthy to mention here that there are two enigmatic monobasic tachyporine genera, i.e., Tachinoporus and Tachinoproporus, described from Malaysian Borneo. No additional specimen of either genera has been known since the original descriptions [11]. In this study, I was fortunately to be able to examine these type materials deposited in the BMNH, which had been under a long-term loan, resulting in limited available information for a long time. Consequently, there have been no photograph, line drawing, or redescription published for these taxa despite their importance in tachyporine systematics. Here, I provide informative photographs and detailed descriptions below, along with discussions of their phylogenetic affinities. However, I refrained from including the genera in my phylogenetic analyses because these specimens seem very fragile, and I was allowed only to observe them from dorsal and lateral views. Furthermore, it was either impossible to score some important morphological characters or difficult to score characters accurately. In this study, I did not detach the glued specimens from the paper cards, to avoid further damage to the specimens (e.g., erect setae, setose surface of the abdomen, repaired hindleg, and well-organized antennae). This also prevents degradation of DNA information of specimens through resolution with water. Unfortunately, some body parts, such as male genitalia, are missing or embedded in glue, preventing accurate scoring of morphological characters. Although the overall conditions of Tachinoporus and Tachinoproporus are rather poor, these specimens allow for the elucidation of tribal affinities, in addition to other information. In conclusion, they should belong to Vatesini sensu nov. based on the results of my morphological investigations (see below).

3.2.8. Genus Tachinoporus Cameron, 1928

Tachinoporus Cameron, 1928: 447 [11] (Figures 35–39; Table A1)

Type species: Tachinoporus basalis Cameron, 1928 [11]: 448.

Differential diagnosis: This enigmatic genus can be distinguished from all remaining genera of Vatesini sensu nov. by the following combination of characters: Body large, slender, antennae longer than head and pronotum combined, devoid of dense and fine recumbent setae in basal three antennomeres, pronotum widest in middle, with longitudinal sulcus along midline, bearing stout setae along margins, elytron somewhat strongly elongate, with stout setae, legs long and slender, abdomen with two pairs of paratergites, and abdominal terminalia with very long macrosetae in both sexes.

Emended diagnosis based on dorsal and lateral views: Body large (more than 5.5 mm long), slender, rather streamlined, moderately depressed dorsoventrally (Figures 35A,C,D and 36A,C–E); surface strongly glossy, dorsum lacking microsetae, punctation, or micro-reticulation on forebody; head with arcuate sides, lacking narrowing of neck region, dorsum with markedly developed midcranial suture, extending posteriad beyond middle of vertex (Figure 37B); antenna filiform, not flattened nor modified, moderately longer than head and pronotum combined, basal three antennomeres devoid of dense and fine recumbent setae (Figure 37A); maxillary palpomeres 3 and 4 glabrous with several setae on surface near each apex (Figure 37C); pronotum as long as wide, widest in middle, surface with inconspicuous longitudinal sulcus along midline (lsp), sides strongly arcuate, all pronotal margins furnished with row of macrosetae (Figure 37B); elytron rather strongly elongate (length/width = ca. 2.0×), dorsoventrally flattened, with several macrosetae along lateral margin (Figure 38A–C); elytral epipleuron rather deeply folded inward, visible from lateral view (Figure 38D); legs long and slender (e.g., Figures 35A,C and 36A,C); abdomen slender, with two pairs of paratergites on segment III–VII (Figure 39F, pts), furnished with distinctly long macrosetae on both dorsal and ventral sides of abdomen; tergite VIII and sternite VIII somewhat strongly elongate, each furnished with several long macrosetae, some of which extremely long: male tergite VIII (Figure 39A) with weakly developed lobes, female tergite VIII (Figure 39D) with moderately to strongly developed lobes, male sternite VIII (Figure 39B) with posterior margin deeply and narrowly emarginate, female sternite VIII (Figure 39E) with weakly to moderately developed lobes, flanking distinct median emargination; male tergite IX (Figure 39C) with each side forming pointed lobe, with several macrosetae on its apical surface; female tergite IX (Figure 39H) subtriangular, weakly transverse, uniformly well sclerotized, with several spines at each apex.

Redescription based on dorsal and lateral views: Body (Figures 35A,C,D and 36A,C–E) large, narrowly elongate, moderately flattened dorsoventrally, Cileoporus-like, widest in pronotum. Dorsum strongly glossy; head and pronotum without ground setae, punctation, or grooves.

Head (Figure 37B,D) hexagonal, slightly transverse, moderately produced anteriorly, widest across eyes, with gently arcuate postocular sides; frontoclypeal suture (Figure 37B) complete, well-developed, shallowly grooved, weakly V-shaped; midcranial suture (Figure 37B, mcs) distinctly developed, extending posteriad beyond middle of vertex; neck constriction or narrowing completely absent in postocular areas (Figure 37B); dorsal surface lacking microsetae, punctation, or ocular seta (Figure 37B); ventral surface without infraorbital ridge extending ventrally from posterior margin of eye. Clypeus (Figure 37B) normal, not reflexed upward, narrowly produced anteriorly. Eyes (e.g., Figure 37A,B,D) moderate in size, somewhat inconspicuous, nearly even with surface of head capsule. Antennal insertions (Figure 37A,D) partially concealed under frontal shelf-like projections, located near anterior margins of eyes. Antenna (e.g., Figure 37A) comprised of 11 antennomeres, filiform, very slender, long, clearly longer than head and pronotum combined; antennomeres 4–11 (a4–a11) slightly flattened; basal three antennomeres glossy, devoid of dense and fine recumbent setae, remaining antennomeres densely covered with whitish microsetae. Maxillary palpus (Figure 37C) four-segmented, elongate, moderate in size and length, lacking recumbent microsetae on surface; palpomere 1 (mp1) very short; mp2 long, narrowly elongate, moderately curved, gradually strongly dilated apically, with several short setae on surface near apex; mp3 very short, as long as wide, much shorter than mp2, weakly dilated apically, with several setae on surface near apex; mp4 markedly long, approximately three times as long as mp3, moderately longer than mp2, moderately narrower than mp3, sides gradually and evenly tapering from middle to pointed apex. Labial palpus (Figure 37E) three-segmented, elongate, inconspicuous, lacking ground microsetae on surface; palpomere 1 (lp1) very short, only partially visible; lp2 slightly longer; lp3 slender, much longer and clearly narrower than lp2, as long as lp1, gradually narrowing toward apex, rather pointed, with more than ten pores on surface. Mentum (Figure 37E) moderately transverse, trapezoidal, with truncate anterior margin. Labium with ligula large, developed, extending laterally.

Pronotum (e.g., Figure 37B,D) oval, feebly transverse, widest in middle, much larger than head; sides strongly arcuate, evenly convex; each margin with a few macrosetae, but lacking ground microsetae; anterior margin weakly concave; anterolateral angles rounded; disc with shallow and very narrow longitudinal sulcus along midline (see, arrow of lsp), but reaching neither anterior nor posterior margins of pronotum. Scutellum (Figure 38A,B) visible dorsally, sub-triangular, as long as wide, with rounded apex. Elytron (e.g., Figure 38A–C) rather strongly elongate (length/width = ca. 2.0×, male, n = 1), subparallel sided, dorsoventrally flattened, only slightly longer than pronotum, with rounded posterior margin; lateral margins not arcuate, with a row of several long macrosetae; surface even and smooth, rather densely covered with vestigial ground microsetae. Elytral epipleuron (Figure 38D) relatively deeply folded inward, but visible from lateral view. Wings (Figure 38A,B) visible, probably fully developed. Mesoventrite (Figure 38D) with surface even and smooth, without carina or keel along midline.

Legs (e.g., Figures 35C, 36C, and 38E–G) long, distinctly slender, with irregularly distributed, somewhat inconspicuous spines on tibiae. Procoxae (e.g., Figure 38E) large, expanded; protibiae (e.g., Figure 38E) rod-like, with markedly long apical tibial spurs, longest spur much longer than protarsomere 1 (pt1); protarsi (e.g., Figure 38E) 5-segmented, narrow in both sexes, moderately shorter than protibiae, basal four tarsomeres each small and short, together moderately longer than pt5. Mesotibiae (e.g., Figure 38D,F) with developed spurs at each apex, but much shorter than mesotarsomere 1 (mst1); mesotarsi (e.g., Figures 36C–E and 38F,G) 5-segmented, very long, as long as mesotibiae, mst1 (Figure 38F) much longer than mst2, as long as mst5. Metacoxae transverse, moderate in size; metacoxal ventral lamella projecting posteriorly in mesial inner areas (Figure 38D); metatibiae with only weakly developed, very short spurs at apex; metatarsi (e.g., Figures 36C,E and 38F) 5-segmented, markedly long, slightly longer than metatibiae, basal metatarsomere much shorter than following three segments combined (see Campbell [103]). Claws (e.g., Figure 38E) simple, lacking conspicuous basal teeth. Empodial setae very short, inconspicuous, not extending distally beyond level of basal fourth of tarsal claw.

Abdomen (e.g., Figures 35C,D and 36C) narrowly elongate, slightly triangular, evenly tapering from base to apex; maximum width moderately narrower than elytra; surface sparsely covered with fine short setae, lacking V-shaped punctures, but with several macrosetae even on tergites. Abdominal segments III–VII each with two pairs of paratergites, large in size, vertical (Figure 39F). Abdominal segments III–VI including paratergites, with weakly produced posterolateral margins. Tergites lacking both pruinose spots and basolateral ridges (Figure 39F). Tergite III only feebly visible (in situ, syntype of female of T. basalis), moderately transverse.

Male. Tergite VIII (Figure 39A) rather strongly elongate, with only weakly developed lobes, bearing numerous blackish macrosetae, some of which are extremely long. Tergite IX (Figure 39C) with each side forming elongate lobe, bearing several macrosetae on apical third; ventral side basally fused, not divided by sternite IX at base. Sternite VI with posterior margin truncate, lacking peg-like setae. Sternite VII (Figure 39G) with posterior margin broadly emarginate and concave, surface lacking peg-like setae or spines. Sternite VIII (Figure 39B) moderately elongate, with posterior margin rather deeply and widely emarginate, bearing numerous blackish macrosetae, some extremely long. Sternite IX (Figure 39C) with posterior margin rounded. Genitalia missing; no information available.

Female. Tergite VIII (Figure 39D) strongly elongate, with moderately developed lobes, bearing numerous blackish macrosetae, some extremely long. Tergite IX (Figure 39H) subtriangular on each side, weakly transverse, uniformly well sclerotized; apices of each side with several short spines (see dsp); surface coarsely covered with large, transverse micro-reticulation. Sternite VIII (Figure 39E) moderately elongate, with weakly to moderately developed lobes, bearing numerous blackish macrosetae, some extremely long. Gonocoxites (Figure 39H) moderate in size, gonocoxite II subtriangular, relatively thick, large, as long as gonostylus, with normal, thin setae; gonostylus subconical, narrowly elongate, each apex with long, testaceous macroseta. Spermatheca not visible.

Composition: Only the type species is known [11,21].

Remarks: Tachinoporus is an enigmatic monobasic genus described from Malaysian Borneo [11]. Since the original description in the late 1920′s, there has been no information published regarding this genus, except for a few catalogues (e.g., [21,104]) Due to the significant lack of information, Tachinoporus, together with Tachinoproporus (redescribed below), has been known as one of the most problematic tachyporine genera, although it was placed in Tachyporini in the traditional sense [21]. In the present study, I provide sufficient photographs and descriptions for the genus to unravel its systematic identity. Based on morphological evidence, Tachinoporus can be placed in the newly revised concept of the tribe Vatesini sensu nov. based on the general Cileoporus-like habitus, the structures of the maxillary palpus and sternite VII in the male, and other morphological evidence described above.

Although I have excluded Tachinoporus from the phylogenetic analyses here, it is generally similar to Cileoporus based on the following features ([91]; this study): body slender, rather streamlined; antennae long, with basal three antennomeres devoid of dense and fine recumbent pubescence; pronotum widest at middle, not base or near base; abdomen slender, with distinctly long macrosetae on both dorsal and ventral sides; paratergites comprised of two pairs; tergite VIII and sternite VIII rather strongly elongate, each bearing extremely long macrosetae, and; tergite IX with each side bearing several macrosetae. It is unfortunate that the male genitalia of the single non-type male had originally been lost. However, Tachinoporus can be easily distinguished from Cileoporus by the following characters: midcranial suture much more developed, grooved, extending beyond middle of vertex; antennae filiform, thin, much longer; pronotum as long as wide, surface with inconspicuous longitudinal sulcus along midline, all pronotal margins furnished with row of macrosetae; elytra dorsoventrally flattened, with several macrosetae along lateral margins, and; tergite IX with each side modified to be lobe-like. Some of the characters listed above (e.g., the presence of longitudinal sulcus on pronotum) are quite unusual, or rarely seen, in the Tachyporinae sensu nov. Thus, there is no doubt that Tachinoproporus is indeed a valid and separate genus. Interestingly, Cileoporus, a suspected sister genus, is distributed in Central and South America, possibly implying a biogeographic connection between these two genera. Additional specimens will be needed to clarify more details, including the male genitalia, and to extract molecular information.

3.2.9. Tachinoporus basalis Cameron, 1928

Tachinoporus basalis Cameron, 1928: 448 [11] (Figures 35–39; Table A1)

Type material: Syntype, 1 female: “SYN-|TYPE” < printed blue -bordered round label >, “Co-|type” < printed yellow-bordered round label >, “Tuta|Riv.” < handwritten on rectangular small white label >, “Paratachinus|basalis Cam” < handwritten on rectangular small white label >, “Tachinoporus|basalis Cam” < handwritten on rectangular small white label > “M.Cameron.|Bequest|B.M. 1955-147.” < printed on rectangular small white label >, “Paralectotypus|Tachinoporus ♀|basalis Cam.|des.|W. G. Ullrich 1974|20966 [written vertically]” < handwritten on rectangular small red label >, “Tachinoporus ♀|basalis Cam.|W. G. Ullrich det.” < handwritten on rectangular small white label > (BMNH). See Figure 35B.

Other material: 1 male: “SONCBOLONG.|RES. KEDiRi.|E. JAVA” < handwritten on rectangular small white label with red margin >, “M.Cameron.|Bequest|B.M. 1955-147.” < printed on rectangular small white label >, “Tachinoporus [handwritten]|basalis Cam. [handwritten]|P. M. Hammond|det. 1973 [3, handwritten]|[comp. unique [handwritten]|syntype in BM] [handwritten]” < printed on rectangular small white label >, “♂ [handwritten]|Tachinoporus [handwritten]|basalis Cam. [handwritten]|W. G. Ullrich vid. [vid., handwritten]” < printed on rectangular small white label, upper right corner rectangularly removed >, “Tachinoporus ♂|basalis Cam.|W. G. Ullrich det.” < handwritten on rectangular small white label > (BMNH). New to Indonesia. See Figure 36B.

Comments on material: In the original description of this species, only two female specimens were specified [11]. However, as indicated above, there is a pair of male and female specimens found in the BMNH. They are considered here as conspecific based on general morphological similarity. In both specimens, the ventral sides were not examined to avoid further damage to the valuable material. A paralectotype label written by Dr. Wolfgang G. Ullrich is attached with the female specimen (Figure 35B), which was collected from the type locality. However, the lectotype designation for the type species has never been formally published. In the present study, I am treating the female as a syntype.

In both specimens, the abdominal apices were dissected by a previous researcher and glued on the same paper card with the body (Figures 35A and 36A). In the male, the left foreleg was additionally removed from and attached near the body (Figure 36A,C). It is unfortunate that several body parts are missing in the male specimen, namely the left antenna beyond antennomere IV, left metatarsus, tergite VII, and the genitalia; in addition, tergite VI is heavily damaged. In the female, the left maxilla, labium including the mentum, and abdominal segments VI–VII were also removed from the body and mounted on the same paper card along with the body (Figure 35A).

Type locality: Borneo, Tutau River [11].

Distribution: Borneo (Sarawak, Malaysia), East Java (Indonesia: new country record).

Diagnosis: As for the genus (vide supra).

Redescription based on dorsal and lateral views: Measurements. Syntype: female (n = 1). Body length: 4.98 mm (excluding beyond abdominal segment V); head length: 0.87 mm; head width: 1.08 mm; antennal length: 2.56 mm (right); pronotal length: 1.50 mm; pronotal width: 1.70 mm; elytral length: 1.64 mm (right); elytral width: 0.84 mm (right); metatibial length: 1.51 mm (left). Non-type material: male (n = 1). Body length: 5.72 mm (excluding beyond abdominal segment VI); head length: 0.83 mm (basal area partially concealed by pronotum); head width: 1.12 mm; pronotal length: 1.60 mm; pronotal width: 1.68 mm.

Body (Figures 35A,C,D and 36A,C–E) large, exceeding 5.0 mm in length with complete abdomen. Color (e.g., Figures 35C,D and 36C) generally black to blackish brown, but elytra bicolored with yellowish brown basal areas and blackish brown apical areas; legs and; elytron of male with larger yellowish area than that of female.

Head (Figure 37B,D) medium in size, moderately transverse (width/length = 1.24×, female, n = 1); sides somewhat straight, gradually narrowed posteriorly; surface covered with very minute, dense, transverse micro-reticulation. Antenna (Figure 37A) markedly slender, notably long; antennomere 1 (a1) elongate, rather fusiform, widest in apical quarter, much longer than a2; a2 rather strongly dilated, much narrower than a1; a3 strongly dilated, moderately longer than a2 and a4, only slightly wider than a2; a4–a10 similar in shape and width, elongate, subcylindrical, weakly dilated anteriad; a4–a8 each with long, conspicuous stem; a11 elongate oval, symmetrical, only slightly longer than a10, weakly narrower than a10, with moderately rounded apex. Maxillary palpi (Figure 37C) with approximate relative length of each maxillary palpomere from base to apex: 3.3, 21.7, 7.8, 25.3; approximate relative width of each maxillary palpomere from base to apex: 5.6, 10.4, 8.9, 7.5.

Pronotum (e.g., Figure 37B,D) nearly as long as wide, rather strongly convex dorsally; surface densely covered with very fine, inconspicuous micro-reticulation, comprised of transverse striae. Elytron (e.g., Figure 38A–C) small, strongly elongate (width/length = 1.95×), with sparse yellowish vestigial microsetae; lateral margin lacking epipleural gutter (sensu Herman [25]), each with row of 6–8 blackish macrosetae (Figure 38B); anteromedial area furnished with two stout, but short, blackish macrosetae (Figure 38A,B); surface yellowish brown in apical 3/4 (female; Figure 35C) to 2/3 (male; Figure 38A), yellowish area slightly extending near lateral margin posteriorly, without micro-reticulation.

Legs (e.g., Figures 35C, 36C and 38E–G) long. Protibia (Figure 38E) with very long single apical spur, ca. 1.6 times longer than pt1 (left, male, n = 1). Metatarsus (Figures 36C,E and 38G) with approximate relative length of each metatarsomere from base to apex (left, female, n = 1): 38.5, 25.4, 28.3, 26.8, 44.2.

Abdomen (e.g., Figures 35C,D and 36C) somewhat strongly glossy, covered with transverse, fine, striae-like micro-reticulation. Abdominal tergites (Figure 35D) and sternites IV–V (only ones observable) with two to three pairs of blackish macrosetae.

Male. Tergite VIII (Figure 39A) with two pairs of weakly developed lobes located in mesial area of posterior margin, with addition of another lateral pair of very feebly developed protrusions, each bearing extremely long blackish macroseta, slightly exceeding maximum length of tergite VIII; mesial area shallowly acutely incised between inner lobes; inner lobes short, triangular, moderately longer and narrower than outer lobes, extending moderately beyond level of outer lobes; outer lobes much shorter, rather narrowly rounded; surface sparsely covered with short microsetae and approximately 16 macrosetae. Tergite IX (Figure 39C) with weakly developed secondary lobe near apices of each side. Sternite VII (Figure 39G) with approximately 7–8 pairs of macrosetae, one pair extremely long. Sternite VIII (Figure 39B) with posterior margin widely and deeply emarginate medially (ca. 1/3 length of sternite VIII in depth), with a lateral pair of protrusions; surface sparsely covered with short microsetae and approximately 16 macrosetae.

Female: Tergite VIII (Figure 39D) with two pairs of moderately developed lobes located in mesial area of posterior margin; mesial area acutely incised between inner lobes; inner lobes narrowly elongate, sharply pointed, slightly shorter and much narrower than lateral lobes; outer lobes narrowly elongate, extending slightly beyond level of inner lobes, with rounded apices; surface sparsely covered with short microsetae and approximately 13 macrosetae, one pair even slightly exceeding maximum length of tergite VIII. Sternite VIII (Figure 39E) with two pairs of moderately developed lobes located in mesial area of posterior margin, with addition of another lateral pair of feebly developed projection-like lobes, each projection bearing extremely long blackish macroseta, slightly shorter than maximum length of sternite VIII; mesial area moderately angulately incised between inner lobes; inner lobes triangular, moderately shorter than lateral lobes, with sharply pointed apices; outer lobes narrowly elongate, extending strongly beyond level of inner lobes, with nearly truncate, broadly rounded apices; surface sparsely covered with short microsetae and approximately 6 macrosetae in lateral half.

Remarks: Although the redescription above is based merely on the dorsal and lateral views, I was able to extract sufficient characters for this enigmatic taxon. The single male specimen is generally similar to the female syntype in many aspects. Nevertheless, there is a color variation found in elytra between these specimens: the male has a more extended yellowish area (Figures 36A,C,D and 38A–C) than that of the female (Figure 35A,C,D). Additionally, it should be noted that their localities are rather distant from each other (northern Borneo vs. East Java). Since there are only two specimens available at the present, they are tentatively considered as conspecific. Therefore, the male specimen is herein identified provisionally as Tachinoporus basalis. More material is needed to resolve this issue.

3.2.10. Genus Tachinoproporus Cameron, 1928

Tachinoproporus Cameron, 1928: 449 [11] (Figures 40–42; Table A1)

Type species: Tachinoproporus ferrugineus Cameron, 1928 [11]: 449.

Differential diagnosis: This enigmatic genus can be distinguished from all remaining genera of Vatesini sensu nov. by the following combination of characters: Dorsum matte with micro-reticulation, antenna shorter than pronotal width, devoid of dense and fine recumbent setae in basal four antennomeres, pronotum widest at base, mesoventrite with plate-like keel along midline, elytra weakly elongate, abdomen without macrosetae with two pairs of paratergites, and male aedeagus (internal sac) with developed spines.

Emended diagnosis based on dorsal and lateral views: Body large (at least ca. 4.2 mm long), weakly depressed dorsoventrally (Figure 40A,C–E); surface matte with dense micro-reticulation, less glossy (Figure 41D, E), dorsum lacking microsetae, punctation, or macrosetae; head with arcuate sides, lacking narrowing of neck region; antenna fili-moniliform, not flattened or modified, moderately shorter than maximum width of pronotum, basal four antennomeres devoid of dense and fine recumbent setae (Figure 41B); maxillary palpomere 4 with sides gradually and evenly tapering from middle to apex (Figure 41C); pronotum semicircular, widest at base; elytron short, only weakly elongate (length/width = ca. 1.2×); elytral epipleuron deeply folded inward, resulting in thin, blade-like elytral margins (Figure 41F); mesoventrite with markedly developed, plate-like keel along midline (Figure 40E,F); abdomen strongly tapered posteriorly, with two pairs of paratergites on segments III–VI, lacking macrosetae (except near apex); tergite VIII and sternite VIII in male with only weakly developed lobes; tergite IX with each side forming somewhat pointed lobe, with single macrosetae at apical third on each lobe (Figure 42E); male aedeagus moderately elongate, only very weakly curved; parameres moderately separated from each other in mesial area (Figure 42B); internal sac with conspicuous curved spines (Figure 42B).

Redescription based on dorsal and lateral views: Male. Body (Figure 40A,C–E) large, broadly oval, weakly depressed dorsoventrally, Coproporus-like. Dorsum matte because of dense coverage of large micro-reticulation (Figure 41D, E); head, pronotum, and elytra uniformly glabrous.

Head (Figures 40C–E and 41A) moderately deflexed, transversely oval, widest across eyes, gradually narrowed posteriorly; frontoclypeal suture (Figure 41A) complete, very weakly curved; midcranial suture (Figure 41A) feebly developed; neck constriction or narrowing completely absent in postocular areas (Figure 41A); dorsal surface lacking microsetae or ocular seta (Figure 41A,J); ventral surface without infraorbital ridge extending ventrally from posterior margin of eye. Clypeus (Figure 41A) normal, not reflexed upward, rather moderately produced anteriorly. Eyes (Figures 40D,E and 41A) moderate in size, inconspicuous, barely protruding from outline of head. Antennal insertions (Figure 41A,J) partially concealed under frontal shelf-like projections, located near anterior margins of eyes. Antenna (e.g., Figure 41B) comprised of 11 antennomeres, slender, fili-moniliform, not flattened or modified, about 2/3 as long as maximum width of pronotum, and moderately longer than head width; basal four antennomeres glossy, devoid of dense and fine recumbent setae, remaining antennomeres densely covered with whitish microsetae. Maxillary palpus (Figure 41C) four-segmented, elongate, moderate size and length, lacking recumbent microsetae on surface; palpomere 1 (mp1) very short; mp2 narrowly elongate, weakly curved, gradually dilated apically, with a few short setae on apex; mp3 elongate, much shorter than mp2, moderately dilated apically, with a few short setae on apex; mp4 narrowly elongate, nearly twice as long as mp3, only slightly narrower than mp3, sides gradually and evenly tapering from middle to apex, with pointed apex. Labial palpus with elongate terminal palpomere.

Pronotum (Figures 40C–E and 41D) semicircular, broadly transverse, widest at base, much larger than head; sides strongly arcuate and anterior margin weakly concave, with angulate anterolateral angles; disc uniformly convex upward, margins without macrosetae, lacking ground microsetae. Scutellum (e.g., Figure 41E) dorsally visible, sub-triangular, weakly transverse, with rounded apex. Elytron (e.g., Figure 41E,F) short, convex upward, slightly longer than pronotum, with posterior margin rounded laterally, oblique near suture; surface smooth, lacking setae. Elytral epipleuron (Figure 41F) deeply folded inward, resulting in thin, blade-like lateral and posterior margins. Wings (Figure 40C) probably brachypterous associated with short elytra. Mesoventrite with markedly developed, plate-like keel along midline (Figure 40E,F).

Legs (e.g., Figures 40C–E and 41G–I) relatively short, slender, with irregularly distributed spines on tibiae. Procoxae conical, large; protibiae (Figures 40C–E and 41G) rod-like, robust, with long apical spurs, much longer than protarsomere 1 (pt1); protarsi (Figure 41G) 5-segmented, narrow, short, probably less than half length of protibiae, basal four tarsomeres each short, together slightly longer than protarsomere 5. Mesotibiae (Figures 40C–E and 41H) with spurs at apex, clearly shorter than mesotarsomere 1 (mst1); mesotarsi (Figure 41H) 5-segmented, longer than half length of mesotibiae, mst1 much longer than mst2, basal four tarsomeres combined much longer than mst5. Metacoxae transverse, moderate in size; metacoxal ventral lamella developed; metatibiae (Figures 40C–E and 41I) with short spurs at each apex; metatarsi (Figure 41I) 5-segmented, more than half length of metatibiae, basal metatarsomere much shorter than following three segments combined. Claws (Figure 41G,H) simple, lacking conspicuous basal teeth.

Abdomen (Figure 40C–E) triangular, evenly tapering from base to apex; surface sparsely covered with vestigial microsetae, lacking both V-shaped punctures and macrosetae (with macrosetae only segments VII–IX). Abdominal segments III–VI (Figure 40C) each with two pairs of paratergites, moderate in size. Abdominal segments V–VI including paratergites, with weakly produced posterolateral margins. Tergites lacking both pruinose spots and basolateral ridges. Tergite III (Figure 40C) partly visible, strongly transverse. Tergite VII (Figure 40D) simple, with posterior margin truncate. Tergite VIII (Figure 42C) with only weakly developed lobes, bearing single pair of blackish macrosetae, distinctly shorter than maximum length of tergite VIII. Tergite IX (Figure 42E) with each side forming pointed, bearing single macrosetae at apical third on each lobe; ventral side basally fused, not divided by sternite IX at base; dorsal side divided from base to apex, mesial margins diverging from near base. Tergite X (Figure 42E) normal, elongate. Sternite VI with posterior margin truncate, lacking peg-like setae. Sternite VII (Figure 42A) moderately produced posteriorly, surface weakly shallowly concave along midline in posterior half (slg), densely covered with posteriorly directed, yellowish short spines (not peg-like setae). Sternite VIII (Figure 42D) with weakly developed lobes, bearing two pairs of long, blackish macrosetae distinctly shorter than maximum length of sternite VIII. Male aedeagus (Figure 42B) with median lobe narrowly elongate, only very weakly curved ventrally. Parameres (Figure 42B, prm) simple, not distinctly flattened, very closely appressed to median lobe; moderately separated from each other in mesial area, but contiguous at apex, without setae or minute sensilla on surface. Internal sac of median lobe with numerous conspicuous, well-developed spines (Figure 42B, dsp).

Composition: Only the type species is known [11,21].

Remarks: Tachinoproporus is an enigmatic monobasic genus described from Malaysian Borneo [11]. As with Tachinoporus, there has been no available information for Tachinoproporus since the original description [11], making the genus completely enigmatic. Later workers have only cited the genus in a few catalogues (e.g., [21,104]), and Tachinoproporus was placed in Tachyporini in the old sense [21]. Here, the genus is unambiguously placed in the newly revised tribe Vatesini sensu nov. based on the general Coproporus-like habitus, short antenna, weakly elongate elytra with elytral epipleuron deeply folded inward, and other morphological evidence as described above.

The systematic placement of this genus within Vatesini sensu nov. seems to be firmly convincing in spite of its absence from the phylogenetic analyses here. Nevertheless, Tachinoproporus has several notable features that are not usually found in the tribe or even the subfamily. For example, the dorsal surface of the type species is matte because of the presence of large and dense micro-reticulation, whereas the remaining vatesines have strongly glossy bodies, especially on the head, pronotum, and elytra. Another interesting feature is the complete absence of macrosetae on the abdomen (except for the apex), because the members of Vatesini sensu nov. usually have such macrosetae on at least the ventrolateral sides of the abdomen. The most astonishing feature is the presence of a plate-like, markedly developed keel along the midline of the mesoventrite (Figure 40E,F pkmsv), as this condition has never been found in the other tachyporines during the course of my study. Even though some tachyporines have a carina on the mesoventrite, they are only weakly raised above and far from the condition seen in Tachinoproporus. Last but not least, the structure of the male genitalia is also unique within the subfamily. Indeed, the internal sac of median lobe in the type species has numerous, very strong, conspicuous spines (Figure 42B, dsp). This feature is not found in other tachyporines, but is similar to those found in other different subfamilies: Trichophya (Trichophyinae) or Habrocerus (Habrocerinae). For these reasons, the genus should be treated as valid and not synonymized under either Cilea or Coproporus.

3.2.11. Tachinoproporus ferrugineus Cameron, 1928

Tachinoproporus ferrugineus Cameron, 1928: 449 [11] (Figures 40–42; Table A1)

Type material. Syntype, 1 male [maxilla and abdominal terminalia glued on the paper card near the body]: “Para-|type” < printed-bordered yellow round label >, “Mt. Dulit|3500 f.” < printed on rectangular small white label >, “Tachinoproporus|ferrugineus|Cam.” < handwritten on rectangular small white label >, “M.Cameron.|Bequest|B.M. 1955-147.” < printed on rectangular small white label >, “Lectotypus|Tachinoproporus ♂|ferrugineus|Cam.|des.|W. G. Ullrich 1974|20964 [written vertically]” < handwritten on rectangular red label >, “Tachinoproporus|ferrugineus ♂|Cam.|W. G. Ullrich det.” < handwritten on rectangular small white label > (BMNH). See Figure 40B.

Comments on type material: A total of four specimens, including both sexes, were specified in the original description (Cameron, 1928). However, only the single male specimen described here was found in the BMNH. A lectotype label written by Dr. Wolfgang G. Ullrich is attached with the specimen (Figure 40B), though this designation has not yet been formally published. In the present study, I treat it as one of the syntypes, refraining from assigning it as the lectotype.

The condition of this syntype is relatively good (Figure 40A,C–E), although the abdominal segments beyond VI, left elytron, and left maxilla were originally removed and mounted on the same paper card along with the body. Similarly, the right leg beyond metatibia was originally removed, but re-attached to the body in a reversed orientation (Figure 40A,C–E). The right antenna beyond antennomere 2 is missing.

Type locality: Borneo, Mt. Dulit, 3500 feet [11].

Distribution: Borneo (Sarawak, Malaysia).

Diagnosis: Same as for the genus.

Redescription based on dorsal and lateral views: Male (n = 1). Body (Figure 40A,C–E) 4.24 mm long (measured from anterior margin of head to abdominal apex, as preserved, excluding abdominal segment VII). Color (e.g., Figure 40C) uniformly reddish brown except head and posterior half of elytron darker.

Head (Figures 40C–E and 41A) large (0.85 mm long, 1.17 mm wide), moderately transverse (width/length = 1.38×); sides gradually narrowed posteriorly; midcranial suture (Figure 41A, mcs) visible anteriorly; surface covered with irregular pattern of micro-reticulation. Antenna (e.g., Figure 41A,B) 1.49 mm long; antennomere 1 (a1) elongate, moderately dilated apically, much longer than a2; a2 rather strongly dilated, shorter and narrower than a1; a3 strongly dilated, only slightly shorter than a4, slightly wider than a2; a4 strongly dilated, much shorter than a3, slightly broader than a3; a5 slightly longer than a6, moderately wider than a4; a6–a10 weakly to strongly transverse, gradually broadened toward apex; a11 elongate oval, symmetrical, approximately twice as long as a10, and slightly narrower, with moderately rounded apex. Maxillary palpus (Figure 41C) approximate relative length of each maxillary palpomere from base to apex: 2.7, 22.5, 12.8, 25.0; approximate relative width of each maxillary palpomere from base to apex: 6.3, 9.9, 8.8, 6.9.

Pronotum (Figures 40C–E and 41D) strongly transverse (width/length = 1.79×; 1.07 mm long, 1.92 mm wide), distinctly convex above in cross section, with sinuate posterior margin (Figure 41D); surface covered with irregular pattern of micro-reticulation. Elytron (e.g., Figure 41E,F) small (1.42 mm long, 1.20 mm wide: measured from right elytron), slightly elongate (length/width = 1.18 ×), without setae of any type; lateral margin lacking epipleural gutter (sensu Herman [25]); dorsal surface covered with large, hexagonal micro-reticulation.

Legs (e.g., Figures 40C–E and 41G–I) compact, with 0.97 mm long metatibia

Abdomen (Figure 40C–E) moderately glossy, but covered with transverse, large, wavy micro-reticulation. Tergite VIII (Figure 42C) with two pairs of weakly developed lobes located in mesial area of posterior margin, and lateral pair of very weakly developed projection-like lobes, each presumably bearing a long blackish macroseta which shorter than than maximum length of tergite VIII; inner pair of lobes short, rounded, slightly longer and narrower than lateral lobes, extending slightly beyond level of outer lobes; outer pair of lobes very short, broadly rounded; each lobe with a few short sensory setae along apex. Tergite IX (Figure 42E) with weak protrusion bearing a macroseta laterally at apical third of each pointed lobe. Sternite VIII (Figure 42D) with two pairs of weakly developed lobes flanking mesial area of posterior margin, each bearing a long blackish macroseta, with tiny lateral pair of very weakly developed projection-like lobes, located in between these lobes; inner pair of lobes short, triangularly pointed, somewhat conspicuous, much longer and wider than lateral lobes, strongly extending beyond level of outer lobes; outer pair of lobes very short, inconspicuous, rather narrowly rounded; mesial area relatively widely incised between inner lobes; each lobe with a few short sensory setae along apex. Aedeagus (Figure 42B) with median lobe not slender, rather thick, widest at basal third.

Female (after Cameron [11]). Tergite VIII with two pairs of long lobes, inner pair narrower and longer than outer pair. Sternite VIII with three pairs of long lobes, inner pair broader, separated from each other by deep oval excision, each apex bearing three sensory setae.

Remarks: Although the redescription above is based merely on the single male syntype from the dorsal and lateral views, I could successfully extract both generic and species characters for males. According to the original description [11], the abdominal segment VIII (both tergite and sternite) in the female possesses a few pairs of long lobes (tergite VIII with two pairs, while sternite VIII with three pairs). The inner pair of lobes of sternite VIII is broader than those of the outer pairs, and they are widely separated from each other, each having three spines at the apex (see Cameron [11]).

3.2.12. Tribe Deropini Smetana, 1983

Deropini Smetana, 1983: 272 [23] (Figures 2–5 and 43–47; Table A1)

Type genus: Derops Sharp, 1889 [105]: 418.

Differential diagnosis: Deropini differs from all other tribes of Tachyporinae sensu nov. based on the following combination of characters: body not at all limuloid, dorsum densely finely pubescent, antennae and legs very long, head with slight but distinct neck well behind eyes, lacking midcranial suture, pronotum strongly constricted in posterior half, pronotal hypomeron not strongly inflexed and visible in lateral view, and male sternite VII with dozens of peg-like setae along posterior emargination (modified after Newton et al. [16]).

Emended diagnosis: Body slender, not tachyporine-like (Figure 43 vs. e.g., Figures 14 and 48), dorsal surface densely finely pubescent (Figure 44: 4-2, 53-2, 74-2); antennae and legs very long (Figure 43), but with short metatarsi (Figure 44C: 103-2); head with slight but distinct neck well behind eyes (Figures 8A and 44A: 12-4), lacking midcranial suture; maxillary palpomere 3 glabrous (Figure 45D: 32-3); pronotum constricted basally, its base distinctly narrower than humeral width of elytra (Figure 44A: 49-1); pronotal hypomeron not strongly inflexed, completely visible in lateral view, with very large, triangular postcoxal process (Figure 45E: 61-4); male tergite IX abruptly divergent and separated in basal 1/3 (Figure 47F: 120-1), each apex forming single lobe (Figure 47F: 122-2), usually with only single to several macrosetae (Figures 47F: 123-2); sternite VII in both sexes with broad, semicircular protrusion along basomedial margin (Figure 47A: 128-1); male sternite VII emarginate and concave along posteromedial margin, with dozens of peg-like setae on each side of emargination (Figure 47A: 131-2); male aedeagus with flattened plate-like parameres (Figure 47F: 145-1). Modified after Smetana [23] and Newton et al. [16].

Description: Body (Figure 43) medium, slender, not typical tachyporine-like; surface uniformly covered with dense and fine setae (Figure 44: 3-2, 51-2, 73-1), with relatively conspicuous punctation (Figure 44: 4-2, 53-2, 74-2). Head (Figure 44A) lacking ocular seta and midcranial suture (Figure 44A: 11-0); postocular areas with neck-like narrowing in middle, well behind eyes (Figures 44A and 45A: 12-4). Antenna (Figures 43 and 45C) very long, filiform, without clear pattern of dense and fine recumbent pubescence (Figure 45C: 21-0). Maxillary palpus (Figure 45D: 32-3) elongate, glabrous; palpomere 3 widest at apex (Figure 45D: 30-0), distinctly shorter than palpomere 2 (≤0.7 ×; Figure 45D: 31-1); palpomere 4 sub-cylindrical, only weakly narrowed anteriorly, widest in middle (Figure 45D: 33-1), much longer than penultimate palpomere (Figure 45D: 34-2), with conspicuous scattered pores (Figure 45D: 36-2). Maxillary lacinia (Figure 45D) without unarticulated large, long spine (Figure 45D: 37-0), with numerous short teeth or spines (Figure 45D: 38-1). Labial palpi (Figure 45B: 46-0) narrowly separated at base, much shorter than length of longest labial palpomere; palpomere 3 elongate, widest in middle, not at base (Figure 45B: 40-1), as wide as penultimate palpomere (Figure 45B: 41-1), with conspicuous pores (Figure 45B: 43-2). Mentum weakly to moderately transverse, with truncate anterior margin. Pronotum (Figure 44A) constricted in posterior half, its base distinctly narrower than humeral width of elytra (Figure 44A: 49-1), without stout setae on dorsum; anterior margin truncate (Figure 44A: 55-0), with angulate anterior angles (Figure 44A: 56-1); posterior margin without conspicuous clusters of blackish pores (Figure 45E: 58-0). Pronotal hypomeron narrow, not widened posteriorly in basal third (Figure 45E: 60-0), not strongly inflexed, completely visible in lateral view, with very large, projecting triangular postcoxal process (Figure 45E: 61-4). Prosternum (Figure 45E) with sternacoxal ridge (tsr) moderately distant from anterior margin of prosternum in medio-lateral areas (Figure 45E: 63-0), with very short prosternal process. Elytron (Figures 43A,B and 44C) elongate, rather long, without macrosetae on dorsum and epipleural gutter along outer margin (Figure 44C: 79-0); lateral side with epipleural ridge or keel, which is only feebly folded inward. Mesoventrite (Figure 46A: 85-0) without longitudinal median carina. Metendosternite with anterior arms thin and inconspicuous. Legs (Figures 43, 44C, 45E,F and 46) very long, slender, with less developed scattered spines on tibiae; procoxae (Figure 45E: 96-1) medium, shorter than profemora; metacoxae (Figure 46B: 98-0) small in each outer lateral half; metatibiae with short metatibial spurs at apex, shorter than 2/5 of metatarsomere 1 (Figure 45F: 101-0); metatarsi (Figure 44C: 103-2) short, less than half length of metatibia. Abdomen (Figures 43 and 44C) tapering somewhat weakly posteriorly, with single pair of paratergites on segments III–VII (Figure 44C: 124-0). First three visible terga with transverse deep impressions (Figure 44C). Tergites III–VII (Figures 43A,B and 44C) without macrosetae (Figure 44C: 109-0), each rather weakly transverse (Figure 44C: 111-0). Tergite VIII (Figure 44C: 114-1) with only a few to several distinct macrosetae; posterior margin in male simple, unmodified, that of female deeply emarginate medially (Asian species) or modified into lobes (North American species; Figure 44C: 117-3). Male tergite IX (Figure 47F) seemingly contiguous and not fused at base of ventral side; dorsal side abruptly divided apically from near base (Figure 47F: 120-1), making each side elongate; apical areas each with at most several long macrosetae, restricted to apices (Figure 47F: 123-2). Sternite III with longitudinal median carina. Sternite VII in both sexes with semicircular protrusion along basomedial margin (Figure 47A: 128-1; see Zhao & Li [106]: Figure 2A); posteromedial margin in male emarginate and concave (Figures 44B and 47A: 129-2, 130-2), with dozens of characteristically arranged with peg-like setae (Figures 44B and 47A: 131-2). Sternite VIII (Figure 47B,E: 133-1) with only a few to several distinct macrosetae; posterior margin in male (Figure 47B) deeply incised or very strongly emarginate medially (Figure 47B: 135-3, 136-2), that of female (Figure 47E) nearly rounded, with slight emargination flanked by a pair of feebly developed projections (Figure 47E: 137-2), each apex with row of sensory setae (Figure 47E: 138-2). Male aedeagus (Figure 47F: 145-1) elongate, rather flattened, with plate-like, flattened parameres longitudinally contiguous (Figure 47F: 143-3). Female genitalia (Figure 47C) with gonocoxite II slender, narrowly elongate (Figure 47C: 153-0), bearing only curved setae (Figure 47D: 155-1).

Composition: One genus, with 20 species. See Table A1 for overview and distributions.

• Derops Sharp, 1889 [105]: 418

Type species: Derops longicornis Sharp, 1889 [105]: 418.

Fossils: No fossil Deropini are currently known.

Remarks: Deropini is the only tribe without any taxonomic change in this study. This monogeneric tachyporine tribe is significant because of the distinct, un-tachyporine habitus (Figure 43). The body shape is not at all limuloid but slender and narrowly elongate. The shape of the pronotum is also unique within the subfamily because it is strongly constricted in the basal half (Figure 44A). Due to the odd-looking habitus, Derops, the sole generic member of this tribe, had been placed in various subfamilies such as Oxytelinae or Phloeocharinae [16,23]. However, it is currently firmly placed within Tachyporinae in the old sense based on both morphological and molecular studies [6,7,23]. One of the most important characters which connects Deropini with Tachinusini stat. rev., sensu nov., within Tachyporinae sensu nov. is the presence of peg-like setae in the male sternite VII and genital features [23,43] (Figures 44B and 47B,F).

Derops has a highly disjunct distribution, most being recorded from East and Southeast Asia (Russian Far East, Korea, Japan, China, Vietnam, and India), but a single species occurs in the eastern part of USA [16,106]. Synonymy of the North American genus Rimulincola Sanderson, 1947 [107] under Derops is maintained here. Derops species are found in wet leaf litter and decayed vegetation in deep rock crevices or along streams, and occasionally in caves [16].

3.2.13. Tribe Tachinusini Fleming, 1821 stat. rev., sensu nov.

Tachinusini Fleming, 1821: 49 [45] (Figures 1D, 2–5 and Figure 48, Figure 49, Figure 50, Figure 51, Figure 52, Figure 53, Figure 54, Figure 55, Figure 56, Figure 57, Figure 58, Figure 59, Figure 60 and Figure 61; Table A1)

=Megarthropsini Cameron, 1919 [101]: 231 syn. nov. (type genus: Megarthropsis Cameron, 1919 [101]: 231).

Type genus: Tachinus Gravenhorst, 1802 [41]: 134.

Differential diagnosis: Tachinusini stat. rev., sensu nov. differs from all other tribes of Tachyporinae sensu nov. based on the following combination of characters: forebody usually glabrous, head usually with neck-like narrowing just behind eyes, sometimes bearing ocular setae, antenna devoid of dense and fine recumbent pubescence in basal two or four antennomeres, maxillary palpomere 4 longer than penultimate palpomere, pronotal hypomeron with long postcoxal process, abdomen rarely with blackish macrosetae dorsally, and male sternite VII usually with a few to dozens of peg-like (or stout) setae along posterior margin.

Diagnosis: Body surface usually glabrous (Figures 50 and 51: 4-0, 53-0, 74-0); head with neck-like narrowing just behind eyes in most taxa (e.g., Figures 50, 51B,D and 58A: 12-3), occasionally much weaker (Figure 51A: 12-0); antenna devoid of dense and fine recumbent pubescence in basal two or four antennomeres (Figure 59C: 21-3); maxillary palpomere 3 distinctly shorter than palpomere 2, usually lacking ground setae (e.g., Figures 53C and 59A: 31-1, 32-2); maxillary palpomere 4 widest in between basal 1/6 to middle, longer than penultimate palpomere (Figures 53C and 59A: 33-1, 34-2); pronotal hypomeron with fully developed postcoxal process (Figures 54G and 59D,E: 61-5); abdomen without blackish macrosetae dorsally (except abdominal terminalia), with exceptions of Nitidotachinus and Leucotachinus; male tergite VIII with lobe-like modifications (Figure 55C: 116-1); male tergite IX abruptly divergent and separated dorsally in basal 1/3 (Figure 55E,F: 120-1), each apex usually forming single lobe (Figures 55G and 61E: 122-2), usually with only single to several macrosetae (Figures 55E,F and 61E: 123-2), except a few genera; male sternite VII usually emarginate and concave along posteromedial margin (Figures 52D, 55A and 61A: 129-1, 129-2, 130-1, 130-2), with variously arranged short and stout setae or peg-like setae (Figures 52D, 55A and 61A: 131-1, 131-2); male sternite VIII with posterior margin deeply emarginate or incised medially, usually associated with lobes (Figures 55B and 61B: 135-5, 136-1, 136-2); female sternite VIII with lobes of most taxa (Figures 55D and 61C: 137-3), with more than three sensory setae at apex of each lobe (Figures 55D and 61C: 138-4); male aedeagus with flattened plate-like parameres in most taxa (Figures 56B and 61F: 145-1).

Description: Body (Figures 48, 49 and 57) medium to large for tachyporines, sub-limuloid; surface generally glabrous (Figures 50 and 51: 4-0, 53-0, 74-0), occasionally covered with inconspicuous microsetae or short, modified setae (Figure 58B,C: 4-5, 53-3); punctation usually absent or inconspicuous (e.g., Figure 51: 3-0, 51-0, 73-0), but sometimes deep, pit-like (e.g., Figure 58A: 51-4, 73-2). Head (Figures 50, 51, 52A, 53A and 58) lacking ocular seta (see Figure 51D: 6-0) or with a short, thin one (Figure 50: 6-1); postocular areas usually with neck-like narrowing, just behind eyes (e.g., Figures 50, 51B,D and 58A: 12-3), but sometimes not (Nitidotachinus; Figure 51A: 12-0) or only slightly narrowed (12-1); clypeus in some taxa reflexed upward (Figure 58A–C: 7-1, 7-2). Antenna (Figures 48, 49, 57 and 59C) long to very long, filiform to fili-moniliform, with clear pattern of dense and fine recumbent pubescence, i.e., lacking such setae on basal two or four antennomeres (Figure 59C: 21-3). Maxillary palpus (Figures 53C,F and 59A: 32-2) elongate, generally lacking ground setae in most cases, except for limited stout setae; palpomere 3 widest at or near apex, distinctly shorter than palpomere 2 (≤0.7×; Figures 53C and 59A: 31-1); palpomere 4 widest in between basal 1/6 to middle (Figures 53C and 59A: 33-1), longer than penultimate palpomere (Figures 53C and 59A: 34-2), usually with conspicuous or inconspicuous scattered pores (Figure 53C: 36-2). Maxillary lacinia (Figure 53C,F) without unarticulated large, long spine (Figure 53F: 37-0), with numerous short teeth or spines in most taxa (Figure 53C: 38-1). Labial palpi (Figure 53B,D,E,G) generally widely separated at base (Figure 53B,D,E,G and 59B: 46-2), but narrowly separated in Nitidotachinus (Figure 53D: 46-0); palpomere 3 elongate, usually widest in middle or near base, but not at base (Figure 53D: 40-1), almost same width or only slightly narrower than penultimate palpomere (Figure 53D,E: 41-1), with conspicuous pores in most cases (Figure 53D: 43-2). Mentum (Figure 53B: 47-0, 48-0) weakly to moderately transverse, with truncate anterior margin. Pronotum (Figures 51 and 58) of typical Tachyporinae sensu nov. form except in Nepaliodes (Figure 58C: 49-4), usually widest between basal 1/4 to middle (Figures 51A,B and 58A: 50-3) [widest at or near base in Tachinomorphus (Figure 51C: 50-0) and Olophrinus (Figures 51D: 50-0)]; disc without stout setae (Figure 51D: 53-0); anterior margin weakly to moderately concave in most examples (Figures 51B and 59D,E: 55-1), usually with rounded anterior angles (Figures 51B, 58A and 59D,E: 56-0); posterior margin sometimes sinuate with conspicuous clusters of blackish pores (Figure 54G: 58-1). Pronotal hypomeron (Figures 54G and 59D,E) moderate to wide in basal third (Figures 54G and 59D,E: 60-1, 60-2), strongly inflexed, not visible in lateral view, with fully developed, long postcoxal process (Figures 54G, 59D, E: 61-5). Prosternum (Figures 54A and 59D) with sternacoxal ridge (tsr) moderately distant from anterior margin of prosternum in medio-lateral areas (Figures 54A and 59D: 63-0), rarely with somewhat long prosternal process (Figure 59D: 64-1). Elytron (Figures 48A–D,F, 49, 51A,C,D, 57A,C–F and 58A,C) elongate, rather long, lacking macrosetae on dorsum, but with very narrow to wide epipleural gutter along outer margin (e.g., Figures 51A,D and 58A,C: 79-1, 79-2, 79-3); lateral side with epipleural ridge or keel moderately to very strongly folded inward (e.g., Figures 52B,C and 58D: 81-1, 81-3); posterolateral margin sinuate in a few genera (Figure 58C: 83-2). Mesoventrite with (Figures 54C,D and 60A: 85-1) or without (Figure 54E,F: 85-0) longitudinal median carina. Metaventrite (Figures 52B,C and 60A) occasionally punctate (members of former Megarthropsini syn. nov. (see Figure 60A) and subgenus Tachinoderus of genus Tachinus), rarely medially carinate on intermetacoxal process ([42]: Figures 188 and 189). Metendosternite (Figure 54H: 90-0) with anterior arms thin to relatively thick, but not strongly lamellate. Legs (e.g., Figures 48D–F, 49A,B,D–F, 52A–C, 57 and 58) moderately long, robust; procoxae (e.g., Figure 52A: 96-0) expanded, large; protarsus in male frequently wider and expanded with adhesive setae ([108]: figures 2 and 3); metacoxae (Figures 52B, 58D, and 60E: 98-0, 98-1) small to medium in each outer lateral half; metatibia with long spurs at apex, clearly longer than 2/5 of metatarsomere 1 (Figures 54I and 60C: 101-1); metatarsus (e.g., Figure 52C: 103-0) short to long, shorter than length of metatibia. Abdomen (Figures 48, 49, 52D and 57) weakly to moderately tapering posteriorly, with single pair of paratergites on segments III–VII, lacking blackish macrosetae dorsally (except abdominal terminalia), with exceptions of Nitidotachinus and Leucotachinus. Tergites III–VII without macrosetae, except Nitidotachinus and Leucotachinus. Tergite VIII (Figure 55C: 114-1) with only a few to several distinct macrosetae, except Nitidotachinus; posterior margin in both sexes usually with lobes (Figure 55C: 116-1), frequently rather strongly modified. Male tergite IX (Figures 55E–G, 61E) fused at base of ventral side, not divided by sternite IX (Figure 61E: 119-1); dorsal side (Figure 55E,F: 120-1) abruptly divided apically in from base, usually forming a slender lobe with pointed apex on each side (Figures 55G and 61E: 122-2) (two each in Olophrinus; Figure 55F: 122-3), or less slender, merely elongate in limited taxa (Nitidotachinus; Figure 55E: 122-1; [109]: Figure 68); apical areas each with at most several long macrosetae, generally restricted to apices (Figures 55E,F and 61E: 123-2). Sternite III with or without longitudinal median carina. Male sternite VI occasionally with characteristically arranged peg-like setae (Figure 52D: 127-1). Sternite VII in both sexes without semicircular protrusion along basomedial margin as in Figure 47A (128-1), but occasionally with basal lateral pair of protrusions (e.g., Figure 61A); posteromedial margin in male emarginate and concave (Figures 52D, 55A, 61A: 129-1, 129-2, 130-1, 130-2), with several to more than a dozen short and stout characteristically arranged setae or peg-like setae (Figures 52D, 55A and 61A: 131-1, 131-2). Sternite VIII (Figures 55B,D and 61B,C) with only a few to several distinct macrosetae (Figures 55B and 61B,C: 133-1), except Nitidotachinus (Figure 55D: 133-0); posterior margin in male (Figures 55B and 61B: 136-1, 136-2) deeply emarginate or incised medially, along with feebly to strongly developed lobes (e.g., Figures 55B, 61B: 135-4, 135-5), that of female (Figures 55D and 61C) nearly rounded or modified: usually with developed lobes and associated smaller internal lobes (Figures 55D and 61C: 137-3), but rarely with only a pair of feebly developed projections, each apex in female typically with row of more than three sensory setae in fan-like arrangement (Figures 55D and 61C: 138-2, 138-4). Male aedeagus (Figures 56A–D and 61F) elongate, usually with more or less wide and flattened, plate-like parameres (Figure 61F: 145-1); parameres longitudinally contiguous or nearly contiguous (Figure 56B: 143-3), rarely separated as in Leucotachinus (Figure 56A: 143-1). Female genitalia (Figures 56E, 61D) with gonocoxite II usually slender, narrowly elongate (Figures 56E and 61D: 153-0) (but rarely rather thick, somewhat triangular), bearing only curved setae in most taxa (Figure 56E: 155-1). Spermatheca (Figures 56F and 61D: 151-1) sometimes complicated, frequently associated with basal coils.

Composition: Fifteen genera (3 extinct), with 371 species (7 extinct). The members of the former Megarthropsini syn. nov. are also included. See Table A1 for overview and distributions. See also Appendix A.

• Austrotachinus Steel, 1956 [110]: 13.
  Type species: Austrotachinus fuscipes Steel, 1956 [110]: 14.
• Lacvietina Herman, 2004 [25]: 39.
  Type species: Lacvietina cuprina Herman, 2004 [25]: 44.
• Leucotachinus Coiffait & Sáiz, 1968 [111]: 411.
  Type species: Tachinus luteonitens Fairmaire & Germain, 1862 [112]: 425.
• Megarthropsis Cameron, 1919 [101]: 231.
  Type species: Megarthropsis decorata Cameron, 1919 [101]: 232.
• Nepaliodes Coiffait, 1977 [113]: 272.
  Type species: Nepaliodes variolosa Coiffait, 1977 [113]: 272.
• Nitidotachinus Campbell, 1993 [109]: 522.
  Type species: Tachinus tachyporoides Horn, 1877 [114]: 94.
• Olophrinus Fauvel, 1895 [115]: 280.
  Type species: Olophrinus striatus Fauvel, 1895: 281.
• Peitawopsis Smetana, 1992 [116]: 199.
  Type species: Peitawopsis monticola Smetana, 1992 [116]: 204.
• Pseudotachinus Cameron, 1932 [117]: 398.
  Type species: Pseudotachinus niger Cameron, 1932 [117]: 398.
• Tachinomorphus Kraatz, 1859 [118]: 54.
  Type species: Tachinus fulvipes Erichson, 1840 [119]: 921.
• Tachinoplesius Bernhauer, 1936 [120]: 326.
  Type species: Tachinoplesius turneri Bernhauer, 1936 [120]: 327.
• Tachinus Gravenhorst, 1802 [41]: 134.
  Type species: Staphylinus rufipes Linnaeus, 1758 [38]: 423.

  -

  Subgenus Latotachinus Ullrich, 1975 [121]: 282.

  Type species: Tachinus punctiventris Sharp, 1888 [122]: 385.

  -

  Subgenus Tachinoderus Motschulsky, 1858 [123]: 217.

  Type species: Tachinoderus longicornis Motschulsky, 1858 [123]: 218.

  -

  Subgenus Tachinus Gravenhorst, 1802 [41]: 134.

  Type species: Staphylinus rufipes Linnaeus, 1758 [38]: 423.

• †Hesterniasca Zhang, Wang & Xu, 1992 [124]: 279.
  Type species: Hesterniasca obesa Zhang, Wang & Xu, 1992 [124]: 279.
• †Mesotachinus Tikhomirova, 1968 [50]: 148.
  Type species: †Mesotachinus major Tikhomirova, 1968 [50]: 148.
• †Protachinus Cai, Yan, Beattie, Wang & Huang, 2013 [52]: 651.
  Type species: Protachinus minor Cai, Yan, Beattie, Wang & Huang, 2013 [52]: 652.

Fossils: The Mesozoic fossils of the newly recognized subtribe Tachinusini stat. rev., sensu nov. have been well documented, mainly from the Jurassic-Cretaceous deposits in China. All named extinct taxa in this tribe are based on compression fossils. Unfortunately, most fossil taxa described by early paleontologists require more detailed studies, and many of these fossils were published with short descriptions, incomplete illustrations, and possibly inaccurate observations [47]. Two Mesozoic fossil genera, †Hesterniasca and †Protachinus, have been placed in Tachyporini under the old sense of the tribe [52,125]. Both genera were considered close relatives to recent members of Tachinus [52,125]. In this study, I tentatively follow their systematic placements based on close external similarities with Tachinusini stat. rev., sensu nov. Although the Lower Cretaceous †Hesterniasca from the Yixian Formation of northeastern China has an unusual combination of characters for the extant Tachinus-related genera (i.e., setose body with contiguous mesocoxae, lacking sexual dimorphisms in tergite VIII and sternite VIII), it generally agrees well with Tachinusini stat. rev., sens. nov. in having long and sub-parallel terminal maxillary palpomeres, longer antennae, broadly arcuate pronotal lateral margins, elongate elytron, posteriorly broadened elytra, only weakly posteriorly tapered abdomen with strongly transverse abdominal tergites III–VI, and the absence of distinct macrosetae on the body, especially those of the abdomen [125]. Similarly, the Upper Jurassic monotypic genus †Protachinus from the Talbragar Fish Bed in New South Wales of Australia also possesses some ambivalent morphological features as in †Hesterniasca, namely the contiguous mesocoxae, abdominal tergites III–VI each with a pair of curved basolateral ridges, without secondary sexual modifications in tergite VIII and sternite VIII. Nevertheless, †Protachinus can be undoubtedly assigned to Tachinusini stat. rev., sensu nov. on the basis of the general body shape, broadly arcuate lateral margins of the pronotum, elongate elytron, posteriorly broadened elytra, only weakly posteriorly tapered abdomen with strongly transverse abdominal tergites III–VI, and the absence of distinct macrosetae on the body, especially those of the abdomen [52]. The presence of distinct discal rows of striae in †Protachinus is unusual in Tachyporinae sensu nov., although such elytral striae can be found in this newly recognized tribe as in Olophrinus (Figures 48F and 51D; [126,127]). Another extinct genus, †Mesotachinus from the Middle–Late Jurassic Karabastau Formation of Karatau in southern Kazakstan [50], with three species, is somewhat problematic, and requires further study and redescriptions of all species using modern techniques including high resolution imaging and SEM (scanning electron microscopy). According to Cai et al. [52], †Protachinus resembles †Mesotachinus as they share some important morphological features, namely, general body shape, small triangular head, transverse pronotum, contiguous pro- and mesocoxae, truncate elytra, and tapered abdomen. Moreover, this fossil genus has a distinctly transverse abdominal segment IV. In the present study, †Mesotachinus is tentatively placed in Tachinusini stat. rev., sensu nov., but future study is needed to clarify its true systematic placement. Some undescribed tachyporines that are being putatively considered here as tachinusines are known from the Middle Jurassic of China, including the misidentified omaliine-like ‘†Protostaphylinus mirus Lin, 1976′ [128] (see Cai & Huang [51] for details). Because the additional specimen recorded as †P. mirus [51,129] seems to be Tachyporinae sensu nov., but the holotype may be attributed to a different subfamily (i.e., Omaliinae [51]). They will definitely be important as future subjects in clarifying tachyporine evolution, although these fossil taxa are removed from the above list and Table A1 to avoid confusion.

In contrast, the Cenozoic fossils of Tachinusini stat. rev., sensu nov. are surprisingly much rarer. For example, only a single, unnamed, Tachinus fossil has been known from the mid-Eocene Baltic amber [64]. Additionally, †Tachinus sommatus Scudder, 1900, has been described from compression fossils from the Eocene Florissant deposit in Colorado, USA [21,68], but there is no convincing evidence that they truly belong to Tachinus.

Remarks: A newly resurrected family-group name, Tachinusini stat. rev., sensu nov. [20,53,130] is used here to accomodate the Tachinus-related genera and the South Asian tribe Megarthropsini syn. nov. The latter tribe has been defined with a combination of the following characters within Tachyporinae [25]: body densely punctured; head with the presence of a neck, with reflexed and explanate anterolateral cephalic margin; elytron with emarginate posterolateral margin; and male aedeagus with ventrobasal groove on median lobe. However, the general morphological structures of the megarthropsines fully agree with Tachinusini stat. rev., sensu nov. For example, the structures of the genital segments and genitalia of both sexes in the megarthropsines are almost identical to those in Tachinusini stat. rev., sensu nov. Additionally, the neck-like narrowing is here confirmed as present throughout the tribe (e.g., Figure 51B,D cf. 58A). Other characters defining Megarthropsini syn. nov. can be considered as more or less derived features (such as deep punctures or reflexed clypeal margins), and they are not necessarily important to maintain the distinct tribal status. In addition to observation of morphological characters, the resulting tree supports this conclusion, although the Tachinusini clade was not supported by bootstrap support value pending future studies if Megarthropsini should eventually be considered as a sister taxon of Tachinusini at a subtribe level (Figures 2–4). A few morphological features of the megarthropsine genus Lacvietina are superficially similar to some of the members of the subgenus Tachinoderus of the genus Tachinus in having the long and slender antennae, punctate elytra and metaventrite, and short metatarsi (cf. [131,132]). However, Lacvietina can clearly be differentiated from Tachinoderus by having the punctate head and pronotum, deep metaventral pit adjacent to apex of the mesosternal process, and reflexed anterolateral margin (clypeus) of the head (Figures 57A, 58A, and 60A,B; cf. [25,133]). They are frequently found from wet micro-environment in forests. In my collecting experience, Lacvietina takashii (Hayashi, 2003) [134] and Tachinus (Tachinoderus) iriomotensis Li, 1994 [135] were found together from very wet leaf litter along stream in Iriomote-jima Is., Okinawa, Japan. Hence, several similar morphologies may be explained by convergence as a result of the adaptations to the semi-aquatic environment. I refrained from using Tachinoderus in the phylogenetic analyses here, because I could not obtain enough samples of T. (T.) iriomotensis, especially those of the females. A hypothesis of the provisionally distant relationship between Lacvietina (or entire Megarthropsini) and Tachinoderus will be tested in future, using all subgenera of Tachinus (Yamamoto, in prep.).

3.2.14. Tachyporinae, incertae sedis: List of Genera with Unknown Systematic Placements within Tachyporinae sensu nov.

• †Abscondus Tikhomirova, 1968 [50]: 151.
  Type species: Abscondus regularis Tikhomirova, 1968 [50]: 152.
• †Tachyporoides Tikhomirova, 1968 [50]: 150.
  Type species: Tachyporoides villosus Tikhomirova, 1968 [50]: 151.

Remarks: Two fossil genera from the Middle–Late Jurassic Karabastau Formation are provisionally considered as “incertae sedis” within Tachyporinae sensu nov., following the taxonomic treatments in Herman [21]. It is almost impossible to extract adequate morphological information from published sources [50], or even from the poorly preserved compression type specimens. Cai et al. [125] briefly mentioned that †Abscondus is similar to †Hesterniasca, an extinct member of Tachinusini stat. rev., sensu nov. Nonetheless, some of the important characters, including those of the maxillary palpus, are not preserved in the type material, preventing further discussion. †Tachyporoides also remains enigmatic because of the significant lack of morphological information in both the fossil and the original description [50]. As suggested by a close similarity to Tachyporus [50], it may belong to Tachyporina stat. nov., sensu nov. (Tachyporini sensu nov.) on the basis of general body shape, large mesocoxae, rather short elytra, and pubescent body. However, the presence of the postcoxal process of the prosternum and seemingly wider tergites are unusual for this subtribe. In any case, further evidence is needed for the taxonomic placement of †Tachyporoides. These fossil taxa should be re-examined with modern imaging techniques and SEM according to the current scientific standard [47].

3.2.15. Subfamily Mycetoporinae Thomson, 1859 stat. nov.

Mycetoporinae Thomson, 1859: 46 [136] (Figures 1E, 2–5, 62–73 and Figure S2A; Table A2)

Type genus: Mycetoporus Mannerheim, 1831 [137]: 476.

Differential diagnosis: Mycetoporinae stat. nov. differ from all other subfamilies of Staphylinidae based on the following combination of characters: body slender and fusiform, head small, frequently elongate, with distinct and complete ridge below eye, antennal insertions fully exposed, located anterior to eyes, mandibles falciform without inner teeth, elytron with longitudinally raised sutural edge, epipleural keel not folded inward, procoxae very large and strongly expanded, tarsal formula 5-5-5, metacoxae markedly large, metatarsi longer than metatibiae, and abdomen with two pairs of paratergites, having very fine ‘brick-wall’ pattern on intersegmental membranes.

Emended diagnosis: Body narrowly elongate, fusiform, somewhat strongly tapered (Figure 62 and Figure 63); head and pronotum uniformly glabrous, except for some macrosetae (not as ground setation) (e.g., Figure 64: 4-0); head small, usually longer than wide (e.g., Figure 64B,D: 1-1, 1-2), with neither midcranial suture nor distinct neck constriction (e.g., Figures 64 and 67C: 11-0, 12-0), ventral side with distinct and complete ridge below eye (Figure 67A,C: 13-2); ocular puncture, usually with its associated seta, located near posterior of each eye (Figures 64A,B and 67B: 6-1, 6-2); antennal insertion fully exposed, located anterior to eye (e.g., Figure 64B,D: 8-1, 9-2, 10-0); antennae unmodified, not extremely slender and verticillate; mandibles without inner teeth (e.g., Figures 67A and 68D: 26-0, 27-0); maxillary palpus 4-segmented; labial palpus 3-segmented, insertions narrowly separated (e.g., Figure 67E: 46-0); pronotum widest in basal 1/4 to middle (e.g., Figure 64B,D: 50-3); pronotal hypomeron narrow, with transverse ridge at apical 1/3 to 1/4 (Figure 69A,B: 59-1); procoxal cavities fully open behind (Figure 69A,B: 66-2); mesospiracular peritremes not well sclerotized, mostly membranous (Figure 69A,B: 67-0); elytron frequently with impressed sutural striae and epipleural keel (Figures 64C, 65, 66A and 69F: 71-2, 71-3, 80-0), with longitudinally raised sutural edge (e.g., Figure 65 and Figure 66A: 78-1); legs with strong tibial spines (e.g., Figure 66A: 95-0); procoxa very large, strongly expanded, with exposed protrochantin (Figures 63C and 70B: 96-3); metacoxae markedly large (e.g., Figure 70A,C: 98-2); tarsi 5-5-5, with very long metatarsus (e.g., Figure 66A: 103-1); abdomen usually covered with roughly V-shaped setigerous punctures (e.g., Figure 66A,B: 110-1), with six visible sternites and two pairs of paratergites on segments III–VII (Figures 63C and 71B: 124-1); intersegmental membranes with very fine ‘brick-wall’ pattern (Figure 71A,B: 107-2); tergite VIII and sternite VIII usually simple, without sexual dimorphisms (Figure 71C–E: 116-0, 135-0, 137-0), but with some exceptions (Figure 71F–H: 134-1, 134-2, 135-1); male tergite IX continuous dorsally in basal half (Figure 72A,B: 120-2, 121-2), with ventral struts (Figure 72C, vs: 118-1), basally separated by sternite IX (Figure 72C: 119-0); male aedeagus with simple and separated parameres (Figure 72E,F: 142-0, 143-0), each paramere bearing longitudinal row of setae (Figure 72D–F: 147-1, 147-2).

Description: Body (Figures 62 and 63) small to medium, fusiform, narrowly elongate, slender; surface strongly glossy; head and pronotum without ground microsetae and punctation (e.g., Figure 64: 3-0, 4-0, 51-0, 53-0); color (Figures 62 and 63) frequently at least partially bright, occasionally having markings or patterns on dorsum. Head (Figures 64 and 67A–C) clearly smaller than pronotum, as long as wide to narrowly elongate, usually longer than wide (Figures 64B,D and 67A: 1-1, 1-2); ocular setae (see Campbell [32]: figures 7–9) located near base of eyes on dorsal head surface (Figure 64A–C: 6-2), except most members of Bobitobus stat. rev. (Figure 64D: 6-0); frontal suture present, but lacking midcranial suture (Figures 64A and 67B: 11-0); tempora or postocular areas without neck constriction (e.g., Figures 64B and 67C: 12-0), but sometimes associated with only weak neck-like narrowing just behind eyes (e.g., Figures 64D and 67A: 12-2); occiput with pair of distinct notches dorsally along posterior margin (Figure 67A,B); ventral side with complete longitudinal basolateral ridges along eyes (Figure 67A,C: 13-2). Dorsal tentorial arms (Figure 67B: 18-0) usually absent or strongly reduced, but developed in earliest diverging genera Parabolitobius and Bolitobius. Hypostomal sutures (Figure 67C: 14-1) fully separated, short, each straight. Gular sutures (Figure 67A,C) widely and fully separated (Figure 67C: 15-0), each rather long, more or less straight (Figure 67C: 16-0). Antennal insertion (Figures 64, 67B, C) located at, or anterior to, anterior margin of eyes (Figure 64D: 10-0), easily visible from above (Figures 64D: 9-2). Antenna (Figures 62, 63, 64B and 68F,G) rather long, slender, fili-moniliform, not verticillate (Figures 64B, 68F, G: 19-0), lacking clear pattern of dense and fine recumbent pubescence (Figure 68F,G: 21-0), except Neobolitobius. Labrum (Figures 64A,B and 67D: 24-0, 25-0) usually lacking setose or spinose processes in middle and lateral areas along anterior margin. Mandible (Figures 67A,B and 68D) falciform, sharply pointed, lacking subapical inner tooth (Figures 67A,B and 68D: 26-0, 27-0), with rather small molar lobe. Maxillary palpus (Figures 64, 67A and 68A–D) 4-segmented, moderately long; palpomere 3 not distinctly shorter than maxillary palpomere 2 (>0.7×; Figure 68A: 31-0); palpomere 4 usually with pores (e.g., Figure 68E: 36-2). Labial palpus (Figure 67A,E,F) 3-segmented, thick, relatively conspicuous; palpomere 3 (Figure 67F: 40-1) widest around middle or near base, not at base, in most taxa, with inconspicuous pores (Figure 67F: 43-1); insertions of labial palpi only narrowly separated (e.g., Figure 67E: 46-0). Ligula (glossae) small, restricted to median area, occasionally associated with medial premental lobes (Bryoporus), not extending beyond each labial palpus laterally (Figure 67E,F: 45-0). Pronotum (Figures 64 and 65D) widest in between basal 1/4 to middle (Figure 64B,D: 50-3); surface even and smooth, with characteristically arranged macrosetae (Figure 64A,C). Pronotal hypomeron narrow (Figure 69A,B: 60-0), strongly inflexed and not visible in lateral view (Figure 69A,B: 60-0), with transverse ridge at apical 1/3 to 1/4 (Figure 69A,B: 59-1); postcoxal process (Figure 69A: 61-0) absent. Procoxal cavities (Figure 69A,B: 66-2) nearly fully open behind. Mesospiracular peritremes (Figure 69A,B: 67-0) not well sclerotized, membranous. Scutellum (e.g., Figures 65, 66A and 69D,E) with prescutoscutellar suture (pss) (sensu Blackwelder [30]: Figure 4A,C) here referred to as apical carina or ridge (Figure 69D,E, ac) distant from base, lying near middle of scutellum (Figure 69D,E: 68-1); basal carina or ridge (Figure 69D,E, bc) with variations among genera from linear to curved, pointed, and divided [32,33]. Elytron (e.g., Figures 65, 66A and 69F) relatively long, elongate (length/width: >1.8×; Figure 69F: 70-0), exposing most of abdomen; lateral side with epipleural ridge or keel (Figure 64C: 80-0), epipleuron only very weakly or not at all folded inward (Figure 69F: 81-0); sutural edge clearly longitudinally raised (Figures 65C and 66A: 78-1); surface with rows of setigerous punctures (see Figure 65A,D: 71-2, 71-3). Mesocoxal cavities (Figure 70A,D,E) large, occupying larger area on metaventrite (Figure 70A). Metendosternite (Figure 69G) without median process (Figure 69G: 92-0), but with posterolateral arms (Figure 69G: 91-1) and lamellate anterior arms (Figure 69G: 90-2). Legs (Figures 62, 63 and 66A) with 5-5-5 tarsal formula and strongly developed tibial spines (Figure 70C: 95-0); protrochantin well exposed; procoxae (Figures 63C, 70B) very large, strongly expanded, even larger than profemora (Figure 70B: 96-3); mesocoxae (Figure 70A,D,E) narrowly separated in most taxa (Figure 70A,E: 87-0), rarely contiguous (Figure 70D: 87-1); metacoxae (Figure 70A,C) markedly large (Figure 70A and Supplementary Figure S2: 98-2), contiguous, without ventral lamellae (Figure 70A, C: 100-0); metatarsi (Figure 66A,B) distinctly long, much longer than metatibiae (Figure 66A: 103-1). Abdomen (Figures 62, 63, 66A and 71A,B) gradually tapering from base to apex, with six visible sternites; two pairs of paratergites (Figures 66A and 71B) per segment on segments III–VII (Figure 71B: 124-1); intersegmental membranes with very fine ‘brick-wall’ pattern (Figure 71A,B: 107-2); surface frequently covered with setigerous V-shaped punctation punctures (Figures 66A,B and 71B: 110-1); tergite VII sometimes with distinct row of white palisade setae along posterior margin ([138]: Figure 15); tergite VIII and sternite VIII usually simple without sexual dimorphisms (Figure 71C–E: 116-0, 135-0, 137-0), but occasionally modified (Figure 71H: 135-1) and/or with characteristically arranged thin or peg-like setae (Figures 66B and 71F–H: 134-1, 134-2). Male genital segments (abdominal segments IX and X): tergite IX (Figure 72A–C) continuous dorsally in basal half (Figure 72A,B: 120-2, 121-2), basally separated by sternite IX (Figure 72C: 119-0), with ventral struts (Figure 72C: 118-1). Male genitalia: aedeagus (Figures 66C and 72D–F) with parameres simple, widely separated from each other and from median lobe (Figure 72F: 142-0, 143-0), with rows of parameral setae (Figure 72D,E: 147-1, 147-2); internal sac without prominent spines (Figure 72E: 141-0). Female genital segments (Figure 73A,B,D: 139-1) moderately to strongly elongate; basal area of tergite IX well sclerotized (Figure 73B: 140-0). Female genitalia: gonocoxites (Figure 73A,B,D) present, distinct and large, well sclerotized; gonocoxite II thick, narrowly elongate (Figure 73A: 153-2), well-sclerotized, much larger than gonostylus (Figure 73A: 154-1), usually covered with normal, non-curved setae (see Figure 73B: 155-0); gonostylus (Figure 73A,B,D) minute, inconspicuous (Figure 73D: 156-1), with apical seta.

Composition: Sixteen genera (4 extinct), with 444 species (10 extinct). See Table A2 for overview and distributions. The type species of Mycetoporus and Ischnosoma and their type species are followed the decision (Opinion 1726) made by the ICZN [139].

• Bobitobus Tottenham, 1939 [140]: 225 stat. rev.
  Type species: Staphylinus lunulatus Linnaeus, 1767 [94]: 684.
• Bolitobius Leach, 1819 [141]: 176.
  Type species: Megacronus castaneus Stephens, 1832 [142]: 166.
• Bolitopunctus Campbell, 1993 [33]: 29.
  Type species: Bryoporus muricatulus Hatch, 1957 [143]: 127.
• Bryophacis Reitter, 1909 [144]: 102.
  Type species: Bolitobius rufus Erichson, 1839 [145]: 407.
• Bryoporus Kraatz, 1857 [96]: 452.
  Type species: Tachinus cernuus Gravenhorst, 1806 [58]: 31.
• Canariobolitobius Schülke, 2004 [146]: 1024.
  Type species: Bolitobius filicornis Wollaston, 1864 [147]: 560.
• Carphacis Gozis, 1886 [148]: 14.
  Type species: Staphylinus striatus Olivier, 1795 [149]: (42): 28.
• Ischnosoma Stephens, 1829 [150]: 22.
  Type species: Tachinus splendidus Gravenhorst, 1806 [58]: 24.
• Lordithon Thomson, 1859 [136]: 47 sensu nov.
  Type species: Oxyporus pygmaeus Fabricius, 1777 [151]: 242 (= Oxyporus thoracicus Fabricius, 1777 [151]: 242).
• Mycetoporus Mannerheim, 1831 [137]: 476.
  Type species: Tachinus punctus Gravenhorst, 1806 [58]: 27.
• Neobolitobius Campbell, 1993 [33]: 35.
  Type species: Lordithon varians Hatch, 1957 [143]: 128.
• Parabolitobius Li, Zhao & Sakai, 2000 [152]: 11.
  Type species: Megacronus prolongatus Sharp, 1888 [122]: 460.
• †Cuneocharis Ryvkin, 1990 [153]: 64.
  Type species: †Cuneocharis elongatus Ryvkin, 1990 [153]: 65.
• †Glabrimycetoporus Yue, Zhao & Ren, 2009 [154]: 64.
  Type species: †Glabrimycetoporus amoenus Yue, Zhao & Ren, 2009 [154]: 67.
• †Ryvkinius Herman, 2001 [67]: 55 (= †Mesoporus Ryvkin, 1990 [153]: 63).
  Type species: †Mesoporus gracilis Ryvkin, 1990 [153]: 64; preoccupied, nec. Cameron [155].
• †Undiatina Ryvkin, 1990 [153]: 62.
  Type species: †Undiatina pilosa Ryvkin, 1990 [153]: 63.

Fossils: The fossil records of Mycetoporinae stat. nov. are relatively rare and sparse from both the Cenozoic and Mesozoic. Only a single extinct genus †Glabrimycetoporus Yue, Zhao & Ren, from the Lower Cretaceous Yixian Formation of China, has provisionally been assigned as a fossil taxon of Mycetoporinae stat. nov. Based on the sufficient evidence shown in Yue et al. [154], the systematic placement of this fossil genus is justified. Ryvkin [153] described the fossil genus †Cuneocharis Ryvkin, from the Lower Cretaceous of Daya in Russia, as a member of Mycetoporinae stat. nov. (originally treated as Bolitobiini). This taxonomic assignment may be correct, although the taxon needs redescription with detailed imaging. He additionally established the two Lower Cretaceous tachyporine genera in the same paper and placed them in Tachyporini under the traditional sense, namely †Undiatina Ryvkin from Daya and †Ryvkinius Herman (= Mesoporus Ryvkin) from Semyon (both in Russia). Although these three genera were each originally placed in a specific tribe, Herman [21] treated them as incertae sedis. In the present study, †Undiatina and †Ryvkinius are provisonally treated as Mycetoporinae stat. nov. based on their markedly large mesocoxae and metacoxae. Furthermore, †Ryvkinius has a long abdomen with a longitudinal shallow groove covered with small spines on abdominal sternite VIII [153]. Although no fossil mycetoporines are recorded from Mesozoic amber, I have a Bolitobius-like specimen in mid-Cretaceous Kachin amber from northern Myanmar (Yamamoto, in prep.).

Several named Cenozoic taxa definitely need further studies with modern scientific techniques to confirm their systematic placements at genus or even subfamily level [47]. Four Lordithon species have been described from the Eocene Florissant deposit in Colorado, USA [21,68]: †Lordithon durabilis (Scudder, 1900) [68], †L. funditus (Scudder, 1900) [68], †L. lyelli (Scudder, 1900) [68], and †L. stygis (Scudder, 1900) [68]. Another mycetoporine species, †Mycetoporus demersus Scudder, 1900 [68], has also been described from the same deposit [68]. Unfortunately, few amber inclusions of Mycetoporinae stat. nov. have been known, with only a single described species, i.e., †Bolitobius groehni Schülke, 2000 [156] from mid-Eocene Baltic amber [156]. Nonetheless, I have seen several mycetoporine species in Baltic amber.

Remarks: The tribe Mycetoporini (= Bolitobiini) is here raised to subfamily status following my results and several previous studies (e.g., [6,7]), as Mycetoporinae stat. nov. The overall morphology of Mycetoporinae stat. nov. is apparently quite different from that of the true tachyporines. In fact, important characters, except for the rather strongly tapered abdomen, are shared between the two subfamilies (see Discussion). Therefore, the removal of Mycetoporini from Tachyporinae sensu nov. is justified to make monophyletic taxonomic groups.

3.2.16. Genus Bobitobus Tottenham, 1939 stat. rev.

Bobitobus Tottenham, 1939: 225 [140] (Figures 3 and 4, 62A, 64D, 68E and 72B,E; Table A2)

Type species: Staphylinus lunulatus Linnaeus, 1767 [94]: 684.

Diagnosis: See Campbell [157] and Li et al. [158].

Composition: Thirty-four species, as listed below.

• arcuatus (Solsky, 1871 [159]: 238), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Russia (East & West Siberia, Far East), Japan (Hokkaidô), South Korea, China (Jilin).
  = ohbayashii (Li & Zhao, 1999 [158]: 250) (Lordithon).
• cinctus (Gravenhorst, 1802 [41]: 193), comb. nov. (Tachinus). Distribution: Canada, USA.
  = atricaudatus (Say, 1823 [160]: 158) (Tachinus).
  = gentilis (LeConte, 1863 [161]: 31) (Bolitobius, cited as Boletobius).
• copulatus (Luze, 1902 [162]: 110), comb. nov. (Bolitobius). Distribution: Russia (Siberia), Japan.
  = luzei (Bernhauer, 1929 [163]: 186) (Bolitobius).
  = hokkaidensis (Li & Sakai, 1996 [164]: 254) (Lordithon).
• daimio (Sharp, 1888 [122]: 456), comb. nov. (Bolitobius). Distribution: Japan, South Korea.
• distinctus (Schubert, 1906 [165]: 381), comb. nov. (Bolitobius). Distribution: Pakistan, India.
• elegantulus (Li & Sakai, 1996 [164]: 251), comb. nov. (Lordithon). Distribution: Japan.
• femoralis (Cameron, 1932 [117]: 339), comb. nov. (Bolitobius). Distribution: India (Sikkim, Darjeeling).
• fungicola (Campbell, 1982 [157]: 67), comb. nov. (Lordithon). Distribution: Canada, USA.
• idahoae (Hatch, 1957 [143]: 130), comb. nov. (Lordithon). Distribution: Canada, USA.
• imitator (Luze, 1901 [166]: 735), comb. nov. (Bolitobius). Distribution: Russia (Siberia), Japan (Honshû).
  = hosodai (Katayama & T. Ito, 2010 [167]: 296) (Lordithon).
• indubius (Luze, 1901 [166]: 734), comb. nov. (Bolitobius). Distribution: Russia (Siberia).
• irregularis (Weise, 1877 [168]: 93), comb. nov. (Bolitobius). Distribution: Japan, China.
• kantschiederi (Bernhauer, 1915 [169]: 268), comb. nov. (Bolitobius). Distribution: Uzbekistan.
• kelleyi (Malkin, 1944 [170]: 26), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Canada, USA.
  = angularis (Sachse, 1852 [171]: 122) (Bolitobius, cited as Boletobius) [preoccupied, nec. Stephens [142]: 173 (Bolitobius)].
  = bimaculatus (Couper, 1865 [172]: 61) (Bolitobius, cited as Boletobius) [preoccupied, nec. Schrank [173]: 644 (Staphylinus)].
• longiceps (LeConte, 1863 [161]: 32), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Canada, USA.
  = elefas (Bernhauer, 1912 [174]: 681) (Bolitobius).
• lunulatus (Linnaeus, 1767 [94]: 684), comb. nov. (Staphylinus). Distribution: Europe, Russia, Caucasus.
  = atricapillus (Fabricius, 1775 [175]: 267) (Staphylinus).
  = austriacus (Schrank, 1781 [176]: 237) (Staphylinus).
  = atricapillus (Zetterstedt, 1828 [177]: 65) (Tachinus) [preoccupied, nec. Fabricius [175]: 267 (Staphylinus)].
• maacki (Solsky, 1871 [159]: 236), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Russia (East Siberia).
• nigricollis (J. Sahlberg, 1880 [178]: 104), comb. nov. (Bolitobius). Distribution: Russia (Siberia).
  = lgockii (Bernhauer, 1928 [179]: 13) (Bolitobius).
• niponensis (Cameron, 1933 [180]: 170), comb. nov. (Bolitobius). Distribution: Japan, China.
• notabilis (Campbell, 1982 [157]: 76), comb. nov. (Lordithon). Distribution: Canada, USA.
• obsoletus (Say, 1832 [181]: 51), comb. nov. (Tachinus). Distribution: Canada, USA.
  = sellatus (Sachse, 1852 [171]: 122) (Bolitobius, cited as Boletobius).
• oregonus (Campbell, 1982 [157]: 82), comb. nov. (Lordithon). Distribution: Canada, USA.
• praenobilis (Kraatz, 1879 [182]: 121), comb. nov. (Bolitobius). Distribution: Russia (Siberia).
• principalis (Sharp, 1888 [122]: 456), comb. nov. (Bolitobius). Distribution: Japan.
• pulchellus (Mannerheim, 1830 [137]: 64), comb. rev. (Bolitobius). Distribution: Europe, Ukraine, Russia (European, East Siberia, Far East).
• puncticeps (Luze, 1901 [166]: 733), comb. nov. (Bolitobius). Distribution: Russia (Siberia), China (Heilongjiang).
• quaesitor (Horn, 1877 [114]: 119), comb. nov. (Bolitobius). Distribution: Canada, USA.
  = rostratus (LeConte, 1863 [161]: 32) (Bolitobius, cited as Boletobius) [preoccupied, nec. Motschulsky [183]: 573 (Bolitobius)].
• rostratus (Motschulsky, 1860 [183]: 573), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Russia (Siberia), Armenia, Turkey.
• ruficeps (Bernhauer, 1938 [184]: 20), comb. nov. (Bolitobius). Distribution: China (Manchuria).
• semirufus (Sharp, 1888 [122]: 457), comb. nov. (Bolitobius). Distribution: Japan, South Korea, China.
• speciosus (Erichson, 1839 [145]: 277), comb. nov. (Bolitobius, cited as Boletobius). Distribution: Europe, Russia (European, Siberia).
• takashii (Katayama & T. Ito, 2010 [167]: 294), comb. nov. (Lordithon). Distribution: Japan.
• vandykei (Dethlefsen, 1946 [185]: 71), comb. nov. (Bolitobius). Distribution: Canada, USA.
• variegatus (Bernhauer, 1902 [186]: 698), comb. nov. (Bolitobius). Distribution: Turkey.

Notes on generic name: See details in Blackwelder ([104]: 79).

Remarks: The genus Lordithon has long been divided into two subgenera, namely Lordithon sensu str. and Bobitobus [21,70,157,158,187]. The latter contains far fewer species and has a relatively limited distributional range, basically limited to the Holarctic Region (Table A2). The subgenus Bobitobus was mainly defined by the distinctly elongate head capsule and longer tempora, as well as some other characters of the head and antennae [158]. Nevertheless, such subgeneric division had later been rejected by Schülke [188]. He synonymized the subgenus under Lordithon without formal analysis because Bobitobus can merely be recognized by its ‘elongate’ head capsule and variations found in the entire Lordithon, considering there is only weak evidence in support of the validity of maintaining it as a distinct subgenus [188].

Interestingly, however, in my phylogenetic analyses, Lordithon sensu str. (Lordithon thoracicus thoracicus) and Bobitobus (B. lunulatus comb. nov. = L. lunulatus) were found to be distant from each other, scattered among the other ‘higher’ mycetoporine taxa (Figures 2–4), although major nodes of Mycetoporinae stat. nov. were not supported by the bootstrap support values, and the study design was not aimed for clarifying the internal relationship of this newly recognized subfamily. Therefore, it is noted that this relationship needs to be further tested with more Lordithon species in phylogenetic analysis. Compared to the non-monophyly of the genus Lordithon, the Oriental and Nearctic Bryoporus species were united into a single clade in the resulting tree (Figures 2–4).

Nevertheless, there are several morphological evidences of the distinctness of Bobitobus found in this study. It is noteworthy to mention here that I could not find any trace of ocular seta near the base of the eyes on the dorsal head surface of Bobitobus in the specimens deposited in the FMNH. As far as I know, the presence of these setae is a universal condition among Mycetoporinae stat. nov. (Figure 64A–C), but there is no trace of such setae in Bobitobus (Figure 64D). Nevertheless, a few rare cases in Lordithon sensu str. have been known that such ocular setae are absent or nearly absent as in Lordithon lewisi (Cameron, 1933) [158,180]. Furthermore, the structure of maxillary palpi between Bobitobus and Lordithon is also different (Figures 68D,E). They are moderately elongate and pubescent with somewhat thick maxillary palpomeres 3 and 4 in Lordithon sensu str. (Figure 68D), whereas these segments are nearly glabrous and slender, much narrower in Bobitobus than the conditions seen in Lordithon sensu str. (Figure 68E). The general shape of maxillary palpomeres 4 is also different; it is rather strongly narrowed toward apex from the base in Lordithon sensu str. (Figure 68D: 33-0), but the palpomere is sub-parallel sided in posterior half in Bobitobus (Figure 68E: 33-1; see also [157,158]). Of note, the general shape of labial palpus distinctly differs between them. The labial palpomere 1 is elongate as long as the apical palpomere in Lordithon sensu str. ([157]: Figure 50), while it is transverse and much shorter than the terminal one in Bobitobus ([157]: Figure 49). Additionally, the labial palpomere 3 can be clearly differentiated from each other as it is much narrower than the palpomere 2 in Lordithon sensu str. ([157]: Figure 50), but it is much larger and longer, as wide as the penultimate palpomere in Bobitobus ([157]: Figure 49).

In the present phylogenetic analyses, the type species of Lordithon sensu str. (L. thoracicus) formed a sister group with Bryophacis (Bryophacis smetanai Campbell, 1993 [33]) by moderate branch support (Figure 3). This relationship was supported by four homoplasious synapomorphies (Figure 4): 6-1, head with thin and short ocular seta; 32-0, maxillary palpomere 3 moderately pubescent, with less than 20 setae (> 10); 101-0, apical metatibial spurs short, less than 2/5 of metatarsomere 1; 147-1, paramere with less than five setae. Bryophacis, however, is easily separated from Lordithon sensu str. by having the more densely pubescent maxillary palpomeres 2 and 3, and the shorter maxillary palpomere 4 in comparison with the penultimate palpomere [16,33].

Based on the evidence discussed above, I remove Bobitobus stat. rev. from the synonymy of the genus Lordithon sensu nov. and raise it herein to generic rank. Although the intermediate shape of the head capsule has been known in some Bobitobus [157], as well as the absence of ocular setae rarely in some Lordithon sensu str. [158]. The combination of the discussed characters is useful in recognition of these two taxa as far as I know. Future investigations are particularly needed to assess if these generic assignments are correct for the non-type species of both genera. It would be also desired to investigate whether further generic separation (e.g., South American taxa [188]) from Lordithon sensu nov. is plausible or not.

3.3. Identification Keys

3.3.1. Key to Subfamilies of Tachyporine Group of Subfamilies

• Body various, sometimes distinctive; antennae inserted to vertex, posterior to anterior margins of each eye ([189]: Figure 1.13.1); elytra with posterolateral margins frequently sinuate (cf. Figures 25A and 30C: 83-1, 83-2); elytral epipleural keel absent; male paramere with velum [190,191]; female without gonocoxites (except Gymnusini) … Aleocharinae

-

Body narrowly elongate, fusiform, or sublimuloid; antennae inserted to anterior margins of each eye; elytra with posterolateral margins rarely sinuate; elytral epipleural keel present OR absent; male paramere simple, lacking velum; female with well-sclerotized gonocoxites … 2

2.

Pronotal postcoxal process separated basally by a suture ([16]: Figure 63.22) … Olisthaerinae

-

Pronotal postcoxal process not separated basally by a suture … 3

3.

Antennae extremely slender and verticillate ([189]: Figures 1.22.1, 9.21.1); neck constriction present, strong, distinct all around ([191]: Figure 1.22.1); maxillary palpus 5-segmented, maxillary palpomere 4 (mp4) large and spindle-shaped, mp5 minute and aciculate ([28]: Figure 75) … Trichophyinae

-

Antennae with variations, rarely extremely slender and verticillate (Habrocerinae only; [189]: Figure 1.21.2); neck constriction present OR absent ([191]: Figure 1.21.3); maxillary palpus 4-segmented … 4

4.

Neck with strong constriction, distinct all around; elytral epipleural keel absent … Phloeocharinae

-

Neck without constriction (sometimes with narrowing); elytral epipleural keel present (Figure 52C: 80-0) … 5

5.

Metacoxa uniformly covered with extended ventral lamella (or plates, vlmtc; Figure S3B) … 6

-

Metacoxa without OR with small ventral lamella (see Supplementary Figures S2 and S3A) … 7

6.

Antennae extremely slender and verticillate (Habrocerus) OR fili-moniliform (Nomimocerus) [189,192]; male genitalia modified to complex structure [192] … Habrocerinae

7.

Body fusiform, slender (Figures 62 and 63); head with distinct and complete ridge below eye (Figure 67A, C: 13-2); elytron with longitudinally raised sutural edge (Figures 65C and 66A: 78-1); metacoxae extremely large (Figure 70A); male parameres widely separated from each other, setose (Figure 72D–F) … Mycetoporinae stat. nov.

-

Body usually sublimuloid, except Derops (Figure 43A,B); head without ridge below eye (Figure 26A: 13-0) (rarely with short, incomplete ridge: Leucotachinus and Nepaliodes; Figures 53A and 58D: 13-1); elytron without longitudinally raised sutural edge (Figure 7D: 78-0); metacoxae medium to small (Figure 52B); male parameres very closely appressed to median lobes (Figure 33E,G), glabrous (Tachinomorphus with minute setulae; Figure 56C: 148-2) … Tachyporinae sensu. nov.

3.3.2. Key to Tribes of Tachyporinae

• Habitus distinctive (Figure 43A,B); pronotum strongly constricted in posterior half (Figure 44A: 49-1) … Deropini

-

Habitus usually sublimuloid; pronotum not constricted in posterior half… 2

2.

Elytra pubescent (Figures 7B and 15C: 74-2); antenna basally without clear borderline of dense and fine recumbent setae (Figure 9D: 21-0); maxillary palpomere 3 setose, longer than palpomere 4 (Figures 10A–D and 16E: 32-1) … Tachyporini sensu nov.

-

Forebody glabrous (not covered with long ground setae); antenna basally with clear borderline of dense and fine recumbent setae (Figures 26D and 59C: 21-1, 21-3); maxillary palpomere 3 glabrous (except Mimocyptus, Leucotachinus), shorter than palpomere 4 (except Mimocyptus, Vatesus) (Figures 27A, 45D, 53C and 59A: 32-2, 32-3, 34-2) … 3

3.

Antennae longer than width of pronotum; elytron much longer than wide (length/width: >1.3×); pronotal hypomeron with long and projecting postcoxal process (Figures 54G and 59D,E: 61-5); male sternite VII (s7) with posterior margin emarginate, bearing peg-like setae (most) or short and stout setae (Figures 52D, 55A and 61A: 131-1, 131-2) … Tachinusini stat. rev., sensu nov.

-

Antennae usually shorter than width of pronotum (except Cilea, Cileoporus, and Tachinoporus) (Figure 23B: 20-1); elytron usually slightly longer than wide (length/width: <1.3×, except Cilea, Cileoporus, and Tachinoporus) (Figure 30A,B: 70-2); pronotal hypomeron with short and rounded postcoxal process (Figure 27E–G: 61-1); male sternite VII with posterior margin usually truncate (occasionally emarginate, i.e., Cilea), without peg-like setae or stout setae (Figure 25C: 131-0) … Vatesini sensu nov.

3.3.3. Key to Subtribes and Extant Genera of Tachyporini

• Forebody densely pubescent (Figure 15B, C); protibia with a row of comb-like close-spaced spines along outer margin (Figure 17B,C: 97-1); pronotum without arranged macrosetae; metatarsus very long, much longer than whole length of metatibia (Figure 15D: 103-1); abdomen without paratergites (Figure 15D: 124-2) … 2 (Euconosomatina stat. rev., sensu nov.)

-

Forebody not entirely pubescent, usually glabrous on head and pronotum (Figure 7A–D); protibia without a row of comb-like close-spaced spines along outer margin; pronotum with arranged macrosetae (Figures 7A and 8A); metatarsus long, but clearly shorter than whole length of metatibia (Figure 7E: 103-0); abdomen with single pair of paratergites (Figure 7E: 124-0) … 3 (Tachyporina stat. nov., sensu nov.)

2.

Labial palpomere 3 distinctly expanded, crescent-shaped ([44]: Figure 1) … Euconosoma

-

Labial palpomere 3 not expanded, conical (Figure 16F) … Sepedophilus

3.

Maxillary palpomere 3 widest at or near apex (Figure 10C,D: 30-0) … 4

-

Maxillary palpomere 3 widest around middle, not at or near apex (Figure 10A,B: 30-1) … 5

4.

Body strongly convex in cross-section (Figure 6B); antenna modified, distinctly short, as long as head width (Figures 7C and 9C: 19-2, 20-1) … Lamprinus

-

Body not strongly convex in cross-section (Figures 6A and 7D); antenna less modified, much longer than head width (Figure 6A) … Lamprinodes

5.

Metatarsomere 3 with ventrally modified projection ([22]: Figure 18); pronotum widest between basal 1/5 and basal 1/4 (Figure 8A: 50-2); elytra with long and thick macrosetae (Figure 8A,D) …Symmixus

-

Metatarsomere 3 normal, without ventrally modified projection; pronotum not widest between basal 1/5 and basal 1/4; elytra with inconspicuous macrosetae (Figure 7B) … 6

6.

Body small (length: <1.4 mm [61]), narrow, very slender (Figure 6C); maxillary palpomere 4 short, but very thick, widened at base (Figure 10B and Supplementary Figure S1A); pronotum widest between basal 1/4 to middle (Figure 7B: 50-3); elytron without epipleural gutter along outer margin (Figure 7B: 79-0) … Palporus stat. nov.

-

Body small to medium (length: ≥1.4 mm), somewhat slender (Figure 6F); maxillary palpomere 4 narrowly elongate, much narrower (Figure 10A); pronotum widest between base and basal 1/5; elytron with very narrow and inconspicuous epipleural gutter along outer margin (cf. Figure 7D: 79-1) … Tachyporus sensu nov.

3.3.4. Key to Extant Genera of Vatesini

• Elytron moderately elongate (length/width: 1.3–1.8×, if dissected) (Figure 21B); pronotum widest between basal 1/4 to middle (Figure 37B) … 2

-

Elytron only slightly elongate (length/width: <1.3×, if dissected) (Figure 30A,B); pronotum widest between base and basal 1/5 … 4

2.

Body very slender, streamlined (Figures 21B and 36C); abdominal terminalia with extremely long macrosetae (Figures 21B and 39A–E); tergite VIII and sternite VIII narrowly elongate, with short and indistinct lobes (if present, see Figure 39A,D,E); male tergite IX with each apex elongate, not modified to two lobes ([91]: Figure 62) … 3

-

Body not slender, sublimuloid (Figure 21A); abdominal terminalia without extremely long macrosetae (Figures 31A and 32A,C); tergite VIII and sternite VIII only weakly elongate to transverse, with long and distinct lobes (Figures 31A, 32A, C); male tergite IX with each apex modified to two lobes (Figure 33A: 122-3) … Cilea

3.

Pronotum and elytra with erect macrosetae (Figures 37B and 38A–C); pronotal disc with shallow and very narrow longitudinal sulcus along midline (Figure 37B, lsp); distributed in Oriental region… Tachinoporus

-

Pronotum and elytra without erect macrosetae (Figure 21B); pronotal disc without longitudinal sulcus along midline; distributed in Central and South America … Cileoporus

4.

Antennae and legs with distinct modifications (Figures 26G and 29B,D: 19-2, 93-1) … Vatesus

-

Antennae and legs without distinct modifications … 5

5.

Body minute (length: ca. 1.2 mm) (Figure 21G); midcranial suture absent (Figure 23A: 11-0); male tegite IX with basal 1/3 dorsally contiguous (Figure 33C: 120-0) … Mimocyptus

-

Body small to large, not minute; midcranial suture present (Figure 23B: 11-1) … 6

6.

Forebody matte, not glossy (Figures 40C–E and 41D,E); mesoventrite with extremely large plate-like keel (Figure 40E,F, pkmsv); abdomen in basal half without blackish macrosetae (Figure 40C); male aedeagus with conspicuous spines (Figure 42B, dsp) … Tachinoproporus

-

Forebody glossy; mesoventrite without plate-like keel; abdomen in basal half with blackish macrosetae (Figure 21C–F,H); male aedeagus without spines … 7

7.

Body strongly convex dorsally (Figure 21H); head much smaller than pronotum; antennae shorter than width of head (Figure 23B) … Termitoplus

-

Body not strongly convex dorsally (Figure 21C–E); head moderately smaller than pronotum; antennae longer than width of head (Figure 21C–F) … 8

8.

Body rather flattened dorsally (Figure 21E); forebody with bluish metallic sheen; mesoventrite without any trace of longitudinal carina (Figure 24B: 85-0); distributed only in Africa … Coprotachinus

-

Body moderately convex dorsally (Figure 21C,D); forebody without bluish metallic sheen; mesoventrite with weakly raised longitudinal carina (Figures 24C, 28B: 85-1); distribution cosmopolitan … Coproporus

3.3.5. Key to Extant Genera of Tachinusini

• Head and pronotum with deep, pit-like punctation (Figure 58A–C); clypeal anterior margin weakly to strongly reflexed upward (Figure 58A–C: 7-1, 7-2) … 2 (members of the former Megarthropsini)

-

Head and pronotum without deep, pit-like punctation (Figure 51); clypeal anterior margin not reflexed upward (Figure 50: 7-0) … 5

2.

Habitus distinctive (Figure 57D, E), with highly and very strongly extended pronotal and elytral margins (Figure 58); antenna with apically tapered scape (Figure 58B,C) … Nepaliodes

-

Habitus less distinctive (Figure 57A,C,F), with slightly to strongly extended pronotal and elytral margins (Figure 58A); antenna with subparallel-sided scape (Figure 59C) … 3

3.

Metaventrite with intermesocoxal pit adjacent to apex of mesosternal process (Figure 60A, B: 89-1) … Lacvietina

-

Metaventrite without intermesocoxal pit … 4

4.

Head with postocular vertical carina (Figure 58D: 13-1); antennae long, very slender, reaching beyond posterior margin of elytra (Figure 57C) … Megarthropsis

-

Head without postocular vertical carina; antennae short, slender, reaching only to near middle of elytra (Figure 57F) … Peitawopsis

5.

Abdomen setose with macrosetae on tergites IV–VII (Figure 48D); head without any type of neck or narrowing (Figure 51A: 12-0) … Nitidotachinus

-

Abdomen usually without macrosetae on tergites IV–VII; head with neck or narrowing (Figures 50 and 51B,D: 12-3) … 6

6.

Elytron with distinct rows of punctures (Figures 48F, 51D); male tergite IX with each apex distinctly modified to two lobes (Figure 55F: 122-3) … Olophrinus

-

Elytron usually without distinct rows of punctures (Figure 51C); male tergite IX with each apex not modified to two separate lobes (Figure 55E, G) … 7

7.

Elytron long, concealing more than half of abdomen (Figure 48B,C); head with a pair of ridges basolaterally along underside of eyes (Figure 53A: 13-1); mesoventrite with transverse ridge, lying near base of intercoxal process (Figure 52A and 54E: 86-1) … Leucotachinus

-

Elytron moderately long, not concealing half of abdomen; head without a pair of ridges basolaterally along underside of eyes; mesoventrite without transverse ridge … 8

8.

Elytra covered with reduced, modified setae (Figure 48A); ligula with pair of medial lobes ([110]: Figure 2); distributed in Australia … Austrotachinus

-

Elytra not covered with reduced, modified setae; ligula without pair of medial lobes; distribution nearly all outside Australia … 9

9.

Pronotum widest at base (Figures 49C and 51C); main part of mesoventrite with strongly raised longitudinal carina (Figures 52C and 54C: 85-1); male parameres densely covered with minute sensilla or filiform setulae (Figure 56C: 148-2) … Tachinomorphus

-

Pronotum widest between basal 1/4 to middle (Figure 51B: 50-3); main part of mesoventrite without strongly raised longitudinal carina (Figures 52B and 54F: 85-0); male parameres without minute sensilla … 10

10.

Head with narrow furrows along inner edge of eyes (Figures 50B and 51B); pronotum with furrows near anterolateral margins (Figure 51B: 52-1); mesoventrite with longitudinal carina on mesoventral process and its basal area only ([193]: Figure 2E,F) … Pseudotachinus

-

Head without narrow furrows along inner edge of eyes; pronotum usually without furrows near anterolateral margins (shallow and inconspicuous, if present) … 11

11.

Pronotum with rather strongly sinuate posterior margin (Figure 49F); scutellum markedly enlarged, but with exceptions [194] (Figure 49F); mesoventrite with deep longitudinal furrow along mesoventral process (Figure 52B); male sternite VII with posterior margin very broadly weakly emarginate, bearing inconspicuous modified setae ([194]: Figure 3A,B); distributed in Africa … Tachinoplesius

-

Pronotum with truncate, rounded, or only weakly sinuate posterior margin; scutellum small to medium (Figure 49D,E); mesoventrite without deep longitudinal furrow along mesoventral process; male sternite VII with posterior margin usually somewhat narrowly strongly emarginate, bearing conspicuous modified setae, frequently furnished with dozens of strong peg-like setae; widespread, but not in Africa … Tachinus

3.3.6. Key to Extant Genera of Mycetoporinae

The following key is partly based on Campbell [32,33,157] and Newton et al. [16].

• Head distinctly elongate, with long tempora, lacking ocular setae (Figures 62A and 64D: 6-0); antenna basally distinctly separated from base of mandible by anterior lobe of gena (Figure 64D); antennomere 1 very long and slender (Figure 64D); maxillary palpomeres 3 and 4 combined long and slender (Figure 68D) … Bobitobus stat. rev.

-

Head not distinctly elongate, usually only weakly to moderately elongate (Figure 67A,B), with short tempora, mostly having ocular setae (Figure 64A–C: 6-2); antenna basally contiguous with base of mandible (Figure 64A); antennomere 1 less elongate, thicker (Figure 68F,G); maxillary palpomeres 3 and 4 combined usually somewhat shorter and wider (Figure 68A,B,D) … 2

2.

Maxillary palpomere 4 narrower and slender, not beyond more than 1/2 as wide as penultimate palpomere (Figure 68C) … 3

-

Maxillary palpomere 4 thicker, more than 1/2 as wide as penultimate palpomere (Figure 68A,B,D) … 4

3.

Meso- and metatibial apices bordered by ctenidium of evenly arranged dense equal length spines with two larger and one smaller apical spur ([32]: Figures 103–105); antennae long, even longer than head and pronotum combined (Figure 63D); maxillary palpomeres 2 and 3 densely finely pubescent ([32]: figures 38 and 39); scutellum with basal carina linear ([32]: Figures 76, 77) … Ischnosoma

-

Meso- and metatibial apices bordered by more irregularly arranged numerous unequal spines ([32]: Figures 99–102); maxillary palpomeres 2 and 3 sparsely, coarsely pubescent ([32]: Figures 31–37); antennae shorter than head and pronotum combined (Figure 63F); scutellum with basal carina acutely pointed medially ([32]: Figures 74 and 75) … Mycetoporus

4.

Meso- and metatibial apices with ctenidium of equal length spines, plus 2–3 long spurs, forming a straight edge ([33]: Figures 103–105) … 5

-

Meso- and metatibial apices with numerous unequal spines, forming a jagged edge ([33]: Figures 99–102) … 6

5.

Elytron with 5–6 irregular longitudinal rows of setigerous punctures (Figure 65D); male sternite VIII with patch of 2 or 3 pairs of oblique setae near middle of posterior margin (Figure 71F: 134-1); abdomen rather strongly tapered posteriorly (Figure 62F) … Bryoporus

-

Elytron evenly densely punctate (Figure 65C); male sternite VIII without characteristically arranged microsetae on postero-medial area [152,195]; abdomen weakly tapered posteriorly (Figure 63H) … Parabolitobius

6.

Elytron evenly densely punctate (Figure 62C); labial palpomere 1 short, strongly transverse ([33]: Figure 91) … Bolitopunctus

-

Elytron not evenly densely punctate; labial palpomere 1 weakly transverse to elongate … 7

7.

Labial palpomere 3 longer than labial palpomeres 1 and 2 combined (Figure 67F) … 8

-

Labial palpomere 3 shorter than labial palpomeres 1 and 2 combined (cf. Figure 67E) … 10

8.

Antenna with preapical antennomeres broadly transverse ([138]: Figure 8); abdomen sub-parallel sided in basal 2/3 (Figures 63A,C and 66A) … Carphacis

-

Antenna rather slender, with preapical antennomeres not broadly transverse; abdomen tapering posteriorly … 9

9.

Body large (length: 5.6–10.8 mm [16]); antenna without clear micropubescence borderline, density increasing apically; maxillary palpomere 3 pubescent; pronotum and elytra with dense waves of microsculapture visible only under high magnification (above 100x) [16,33]; elytron usually with more than 6 irregular longitudinal rows of setigerous punctures; male sternite VII with distinct patterns of modified setae (Figure 71G: 134-2); distributed in Holarctic region … Bolitobius

-

Body medium to relatively large (length: <5.6 mm [16,33]); antenna with clear micropubescence borderline, lacking dense and fine recumbent setae on basal four antennomeres ([33]: Figure 104); maxillary palpomere 3 nearly glabrous; pronotum and elytra with distinct waves of coarse, transverse microsculapture easily visible with low magnification (24x) [16,33]; male sternite VII without distinct patterns of modified setae; distributed in North America only … Neobolitobius

10.

Maxillary palpomere 3 moderately coarsely pubescent ([33]: Figures 99 and 100); maxillary palpomere 4 shorter than penultimate palpomere ([33]: Figures 99 and 100); labial palpomere 1 very large, even larger than labial palpomeres 2 and 3 combined ([33]: Figures 87 and 88); scutellum with basal carina distinctly divided medially ([33]: Figure 130) … Bryophacis

-

Maxillary palpomere 3 with sparse setae only; maxillary palpomere 4 equal in length or longer than penultimate palpomere (Figure 68D); labial palpomere 1 large, but shorter and smaller than labial palpomeres 2 and 3 combined; scutellum with basal carina obtusely convex in middle ([157]: Figure 59) … 11

11.

Head with long, strong ocular setae; elytra with rather conspicuous microreticulation; abdomen sub-parallel sided in basal 2/3; distributed in Canary Islands … Canariobolitobius

-

Head with rather short, inconspicuous ocular setae (rarely absent, e.g., L. lewisi [158]); elytra without microreticulation; abdomen strongly tapering posteriorly; distribution cosmopolitan … Lordithon sensu nov.

4. Discussion

4.1. Non-Monophyly of Tachyporinae and Tachyporini

Among one extinct and 32 extant subfamilies of Staphylinidae [1,20], Tachyporinae are one of the most problematic subfamily-level taxa [3,6,7]. Indeed, this problem has been recognized by earlier studies based on evidence from both adults and larvae [26,27,28], but more comprehensive details have been unknown until recently in the absence of broad taxon sampling of Staphylinidae in phylogenetic analyses. Two recent large-scale phylogenies based on molecular data have provided strong evidence for the polyphyly of Tachyporinae [6,7], and greatly expanded our views on tachyporine phylogeny in spite of their weak gene samplings. Both studies have shown that the subfamily is actually divided into two phylogenetically distant clades: the tribe Mycetoporini is widely separated from the remaining core tachyporine members [6,7]. Although the tachyporines without Mycetoporini appear to be monophyletic, it should be mentioned that neither of these studies included Megarthropsini [6,7]. Furthermore, Vatesini was absent from McKenna et al. [6], preventing the assessment of the true monophyly for the tachyporine clade in sensu stricto.

Here, I focused on Tachyporinae phylogeny and classification for the first time to tackle these issues, incorporating the largest and most comprehensive taxon sampling of tachyporine taxa ever in history. By using museum collections including historical material, it was possible to directly examine all forty extant tachyporine genera (except Urolitus syn. nov., literature only), with the addition of two fossil genera. Of these, a total of 57 species in 38 genera of Tachyporinae were used in the phylogenetic analyses. Although my dataset is limited to adult morphology, it provides a backbone to the phylogeny and relationships within the tachyporines. My results were consistent with the hypothesis of a non-monophyletic Tachyporinae, with a similar topology to that obtained by McKenna et al. [6] and Lü et al. [7]: Mycetoporini appearing in a phylogenetically distant position from the rest of the tachyporines (Figures 2–4). Four tribes, namely Deropini, Tachyporini, Megarthropsini, and Vatesini, together formed a monophylum (Figures 2–4). However, non-monophyly of the largest tribe Tachyporini was again shown in the resulting tree and appeared in nine distinct clades (Figure 2). My results suggested that the current classifications of both Tachyporinae and Tachyporini are more or less artificial based on similar-looking taxa, rather than grouped together under a phylogenetic framework.

4.2. Revised Status of Mycetoporini as a Subfamily

The present and previous studies consistently demonstrated that Mycetoporini is significantly dissimilar from the remainder of Tachyporinae [6,7]. In light of this, I herein revise the traditional concept of Tachyporinae and exclude all members of Mycetoporini from Tachyporinae. Both lineages are monophyletic and morphologically distinctive, and each should be considered at the subfamily rank. Yet, Mycetoporini cannot be assigned to any of the other subfamilies of Staphylinidae; therefore, it is now raised from a tribal rank to the 34th recognized subfamily Mycetoporinae stat. nov. within Staphylinidae, after following the treatment of Staphylininae and their allies in Tihelka et al. [1].

Overall, morphological features clearly support this treatment. For example, mycetoporines are usually defined by a series of distinctive characters that clearly separate them from Tachyporinae sensu. nov., such as: head usually elongate, lacking midcranial suture, ventral side with distinct ridge below eye; antennal insertion fully exposed; ligula small, restricted to median area; pronotal hypomeron with transverse ridge at apical 1/3 to 1/4 (see Figure 69A,B); elytron frequently with impressed sutural striae, with longitudinally raised sutural edge; metacoxae markedly large; abdomen usually covered with V-shaped setigerous punctures, having intersegmental membranes with ‘brick-wall’ pattern; tergite VIII and sternite VIII without lobe-like modifications; male tergite IX continuous dorsally in basal half, with ventral struts, basally separated by sternite IX; parameres separated from median lobe, each with a row of parameral setae at least partially aligned; gonocoxite II very large in comparison to gonostylus, bearing only normal setae. These features are not at all, or very rarely, found in Tachyporinae sensu. nov. Given the overall topology of my phylogenetic tree and consideration of these morphological characters, this taxonomic treatment can be justified, as previously suggested by Gusarov [196].

4.3. New Higher Classification of Tachyporinae

With the exclusion of Mycetoporini from the traditional concept of Tachyporinae, not only the taxonomic treatment of Mycetoporini but also that of the remaining tachyporine clade is now revised. The new concept of this subfamily is unique among the other staphylinid subfamilies in having the following morphological characteristics: head with midcranial suture; ligula transverse and markedly large; tergite VIII and sternite VIII frequently with lobe-like modifications; parameres very closely appressed to median lobe, with apically contiguous to only weakly separated apical inner margins; gonocoxite II small in comparison with gonostylus, bearing curved setae. These features define the tachyporines more accurately than the traditional circumscription, which was merely based on characters such as the more or less tapered abdomens and more or less retractile head.

My analyses and examinations of the specimens resolve the backbone relationships within Tachyporinae sensu nov. The new division of this problematic group significantly improves its classification by naming monophyletic units as tribes, with diagnostic characters for identification. Until the present study, a total of five tribes have been recognized within Tachyporinae, including Mycetoporini. Here, I have incorporated only four tribes into the subfamily: Tachyporini sensu nov. (Tachyporina stat. nov., sensu nov. and Euconosomatina stat. rev., sensu nov.), Vatesini sensu nov., Deropini, and Tachinusini stat. rev., sensu nov. (= Megarthropsini syn. nov.). All but Deropini are now redefined under the new concepts mentioned in detail above.

The monogeneric tribe Vatesini is combined together with the Coproporus-related genera of Tachyporini in the traditional sense, and it was fully nested within this clade (Figure 2). Interestingly, however, a close relationship between Coproporus and the sole vatesine genus Vatesus has been suggested by morphological evidence for both adults and larvae [25,27]. It is notable that Vatesus and Coproporus were shown to be sister groups supported by four unique synapomorphies based on a dataset comprised of 27 larval morphological characters ([27]: see also Figures 1 and 2 in Ashe [28]). Later, a similar hypothesis was obtained from the morphology-based parsimony analysis using 19 adult characters [25]. Coproporus fell into the same clade as Vatesus. However, Herman’s study was focused only on Megarthropsini, and he did not intend to examine the tribal relationships within Tachyporinae ([25]: 64). Nevertheless, he mentioned the close similarity of adult morphologies between Coproporus and Vatesus by removing the autapomorphic features of Vatesus acquired through their adaptative evolution with army ants ([25]: 65). Consequently, my result is not very surprising, but the more detailed comparison made here provides firm evidence for supporting this conclusion.

Another small tribe, Megarthropsini, is no longer considered as a valid tribe in this study. Herman [25] made a comprehensive revision of Megarthropsini and also provided a preliminary phylogenetic hypothesis. His phylogenetic analysis recovered Megarthropsini as a monophyletic tribe with Deropini as its sister group. I agree with the opinion that the megarthropsines are distinct among other tachyporines in having raised and explanate lateral margin of the frons, pronotum or elytra and aside from these characters, there are several additional characteristic features that are uniquely found in the tribe [25]. According to Herman [25], an important character state that supports Megarthropsini and Deropini as sister groups is the presence of a broad, distinct neck. This state, however, is also seen in the Tachinus-related genera (e.g., Figure 51B,D). Thus, this proposed relationship is less strongly supported than Herman suggested. Indeed, most characters and even the general habitus of the megarthropsines agree well with those of the Tachinus-related genera. My phylogenetic analyses have shown the monophyly of Megarthropsini, but it was resolved as a part of the former Tachyporini (Tachinus-related genera), reflecting the morphological similarities between them. Consequently, the tribal status should no longer be maintained; and thus, Megarthropsini syn. nov. is now synonymized under Tachinusini stat. rev., sensu nov.

Tachyporini in the traditional sense has been the most problematic tribe among the tachyporine tribes; it has been inferred to be paraphyletic without any synapomorphy for a long time. Such a conclusion was drawn from both morphological and molecular evidence [6,7,25,27,28,196]. Compared to above mentioned Ashe & Newton [27] and Herman [25], more data were used in Ashe [28] to investigate the internal relationships within the Tachyporine Group of subfamilies based on 133 adult characters and 27 larval characters. In his study, both Tachyporinae and Tachyporini were not supported to be monophyletic [28]. More recently, two molecular-based studies have demonstrated such paraphyly in Tachyporini with respect to Deropini [6] or Tachyporini and Vatesini [7]. Only two molecular markers, i.e., 28S ribosomal RNA and the nuclear protein-coding carbamoyl-phosphate synthase domain (CAD), were used in McKenna et al. [6], whereas six genes were analyzed in Lü et al. [7]: two nuclear protein-coding genes, CAD and wingless (Wg); two nuclear non-coding genes, 28S and 18S rDNA; two mitochondrial genes, one coding Cytochrome b (Cyt b) and one non-coding 16S rDNA. The results of both studies on the tachyporines resemble each other, although that of McKenna et al. [6] should be considered weakly supported in this respect. Nonetheless, these studies targeted various phylogenetic and evolutionary questions within Staphylinoidea or Staphyliniformia, and one can conclude that no study had actually focused on the monophyly of Tachyporini previously. After my thorough study and reclassification, Tachyporini is now treated in a strictly limited sense. Tachyporini sensu nov. contains only eight genera (one extinct) with two newly assigned subtribes: Tachyporina stat. nov., sensu nov. and Euconosomatina stat. rev., sensu nov. Considering the distinctive features of Sepedophilus and its relatives (e.g., absence of paratergites), it seems reasonable to apply these subtribal divisions. The remaining members of the former Tachyporini were placed in different clades in my analyses and therefore in other tribes, producing a reclassification of the subfamily. Of note, the monophyly of Tachinusini stat. rev., sensu nov. as defined here was not supported with high support by the molecular analyses of McKenna et al. [6] as Tachinus was separated from the Leucotachinus + Austrotachinus clade. Nevertheless, the study design of McKenna et al. [6] was not at all aimed at Tachyporinae, more specifically the traditional sense of Tachyporini, with only two molecular genes.

With the revised tribal classification of Tachyporinae sensu nov., the long-standing problem of the circumscription of the subfamily and tribal concepts is revisited. There are still several small topics to work on. For example, the next immediate targets are revisiting the systematic validity and placements of the fossil taxa, especially those of the compression fossils. Additionally, phylogenetic assessment of Lordithon sensu nov. and Bobitobus stat. rev. in Mycetoporinae stat nov. and the subgenera of Tachinus (Tachinusini stat. rev., sensu nov.) are also important tasks. I hope that the new classification will be a backbone to Tachyporinae systematics and applied to evolutionary and ecological studies.

4.4. Sister Group of Tachyporinae

Although Tachyporinae have been placed in the Tachyporine Group for a long time, it has been a great challenge to identify a potential sister taxon of Tachyporinae with much confidence, as the subfamily had seemed to be polyphyletic. Consequently, Thayer [3] summarized a more or less ambiguous phylogenetic schema for the Tachyporine group based on previously published literature due to the ‘non-monophyletic’ Tachyporinae.

Interestingly, two recent molecular phylogenetic studies suggested the carrion beetle family Silphidae as a possible candidate for the sister group of Tachyporinae sensu str. [6,7]. In McKenna et al. [6] where Tachyporinae sensu str. was hypothesized to be a close relative of Silphidae, but neither were closely related to the remaining Tachyporine Group of subfamilies, namely: Aleocharinae, Habrocerinae, Olisthaerinae, Phloeocharinae, and Trichophyinae. The clade Tachyporinae sensu str. + Silphidae was resolved in a cluster comprised of eleven other staphylinid subfamilies which included Aleocharinae [6]. In contrast, Tachyporinae sensu str. formed a clade together with Silphidae and altogether were sister to Phloeocharinae (Phloeocharis) in Hunt et al. [197] and Lü et al. [7]. A recent phylogenomic analysis recovered a slightly different phylogeny by analyzing 95 protein-coding genes in 373 beetle species, with limited staphylinoid taxa [198]: Tachyporinae sensu str. formed a sister group to the clade Silphidae + the Oxyteline Group of subfamilies (Apateticinae, Scaphidiinae, and Osoriinae). A close affinity between Silphidae and the Oxyteline Group had earlier been refuted by Grebennikov & Newton [2] based on morphology, but this subfamily group should also be studied in the future as a possible alternate sister taxon to the silphids.

In my analyses, the Tachyporinae sensu str. + Silphidae clade was corroborated by one unique synapomorphy and eight homoplasious synapomorphies (Figure 4), and this lineage was widely separated from Phloeocharinae (Phloeocharis), fully consistent with the hypothesis of McKenna et al. [6]. Despite my results and the several previous works mentioned above, the close relationship with the silphids should be carefully assessed in the future by analysing broader taxonomic sampling and larger datasets. More assessment is needed to address this issue and to determine whether to incorporate Silphidae into Staphylinidae as a separate rove beetle subfamily.

4.5. Sister Group of Mycetoporinae

The newly recognized subfamily Mycetoporinae stat. nov. is apparently monophyletic, but with uncertainty about its sister taxon with a handful recent studies assessing its phylogenetic position [6,7,196]. Indeed, McKenna et al. [6] showed conflicting phylogenetic relationships between the Bayesian and maximum likelihood analyses. In the Bayesian inference tree of McKenna et al. ([6]: Figure 3C), Mycetoporinae stat. nov. formed a sister group with Pseudopsinae (with weak support), subsequently followed by Micropeplinae [6]; these together formed the sister group of the rather unresolved large cluster of subfamilies including the clade Olisthaerinae + (Paederinae + Staphylininae). By contrast, in the maximum likelihood phylogram ([6]: Figure 4B), they recovered the mycetoporines and Pseudopsinae as sister taxa (with weak support), sister to Olisthaerinae (with no support) and all of them sister to Paederinae + Staphylininae (with no support). On the other hand, Lü et al. [7] recovered a similar, but slightly different, topology from the maximum likelihood tree of McKenna et al. [6]: Mycetoporinae stat. nov. was resolved as having a sister group relationship to the grade formed by Olisthaerinae, altogether sister to Paederinae + Staphylininae, although all those nodes had bootstrap support values far below 50.

In congruence with Lü et al. [7], I have recovered generally similar relationships within the selected staphylinid and silphid taxa, resolving Mycetoporinae stat. nov. and Olisthaerinae as sister taxa with moderate support (Figure 3). Staphylininae were recovered as sister to Mycetoporinae stat. nov. and Olisthaerinae combined, fully consistent with Lü et al. [7], though with no support. Overall, the general morphological features of Mycetoporinae stat. nov. are much more similar to Staphylininae or Olisthaerinae than to Tachyporinae sensu nov. or Pseudopsinae, regardless of the notable morphological differences between Staphylininae and Olisthaerinae, particularly based on the structures of mouthparts, prothorax including prosternum, scutellum, elytra, and metacoxae. Given that there are only a few previous studies supporting the close similarity among the mycetoporines, Staphylininae (plus Paederinae), and Olisthaerinae, my results require further data to support this hypothesis; and thus, it should be considered as preliminary and tentative. Yet, these subfamilies will certainly stand as the most plausible candidates for the sister taxon of Mycetoporinae stat. nov.

4.6. Evolutionary Origins and Fossil Records

My updated higher phylogeny and classification of Tachyporinae also triggered substantial changes for evolutionary origins in each taxonomic category. In this study, I reconsider the taxonomic placements of all extinct tachyporine genera as listed above in the Taxonomy section, following such taxonomic changes.

No staphylinid fossil records earlier than the Jurassic nor molecular dating supporting the existence of the tachyporines in the Triassic have been found [7]. On the basis of currently available information, the evolutionary origin of Tachyporinae sensu. nov. can reliably be dated back to at least the Late Jurassic, but based on some problematic or undescribed fossils, it likely dates as far back as the Middle Jurassic, while that of Mycetoporinae stat. nov. can now be traced back to the Lower Cretaceous ([153,154]; see above).

Within Tachyporinae sensu. nov., only a single tribe, Deropini, currently lacks any fossil record at the tribal level, while the three other tachyporine tribes have both Mesozoic and Cenozoic fossils. Note that Tachinusini stat. rev., sensu nov. putatively contains a likely erroneously identified Middle Jurassic fossil specimen of ‘†Protostaphylinus mirus’, as the oldest tachyporine, with some undescribed fossils from the Middle Jurassic Daohugou, northeastern China [51]. Regardless of the systematic positions of these fossils, Tachinusini stat. rev., sensu nov. indeed has a deep evolutionary origin as indicated by the discovery of †Protachinus from the Upper Jurassic of Australia [52]. My phylogenetic analyses and observations provide strong support for Deropini and Tachinusini stat. rev., sensu nov. being sister groups. If correct, then the evolutionary history of Deropini may be dated back to the Late or Middle Jurassic as well. By contrast, the remaining two tachyporine tribes have much shallower geological origins based on fossils, but older examples are presumably just undiscovered, based on deep nodes of the phylogeny presented here. Vatesini sensu nov. has only a single Mesozoic genus †Procileoporus from mid-Cretaceous Kachin amber from northern Myanmar [46]. Given the uncertainty associated with the paucity of fossil records for the vatesines, more discoveries of both impression and amber fossils are desired in spite of their difficulty in identification. With only a single Mesozoic occurrence, Tachyporini sensu nov. also has poor fossil evidence, represented by the extant genus Tachyporus (Tachyporina stat. nov., sensu nov.) from Upper Cretaceous New Jersey amber from the USA ([56]; this study). Nevertheless, Tachyporini sensu nov. or even Euconosomatina stat. rev., sensu nov. will still possibly be found from Burmese (Kachin) amber in the near future considering the enormous and significant fossil records of rove beetles from this deposit. If my phylogenetic hypothesis and its major branching pattern is reasonable, the evolutionary origins of both Vatesini sensu nov. and Tachyporini sensu nov. could be much older, probably tracing back to the Late or Middle Jurassic.

In conclusion, I posit that every tribe-level lineage of Tachyporinae sensu nov. was already established by the Late Jurassic, and the subfamily likely must have originated during the Middle or possibly Early Jurassic.

5. Conclusions

From the phylogenetic analyses and morphological investigations representing all fossil and extant genera, the following conclusions can be drawn:

• Non-monophyly of current Tachyporinae and Tachyporini is again supported. To improve the higher classification of this subfamily, Mycetoporini is removed from Tachyporinae and considered as a newly recognized rove beetle subfamily Mycetoporinae. I reclassify Tachyporinae into four monophyletic tribes: Tachyporini, Vatesini, Deropini, and Tachinusini. The tribe Megarthropsini is synonymized under Tachinusini. Within Tachyporini, two subtribes are newly established: Tachyporina and Euconosomatina. The resulting topology is as follows: Tachyporini + (Vatesini + (Deropini + Tachinusini)).
• Most tachyporine and mycetoporine genera, including disjunctly distributed Leucotachinus, are found to be monophyletic, except Lordithon, Sepedophilus, and Tachyporus. With some taxonomic changes, all genera of both subfamilies appear to be monophyletic for now. After direct examination of the two enigmatic extant genera Tachinoporus and Tachinoproporus, both are indeed true tachyporines and should be considered valid genera. A total of 36 (†7) genera of Tachyporinae and 16 (†4) genera of Mycetoporinae are recognized here.
• The carrion beetle family Silphidae (Silpha) and Tachyporinae might be sister groups, whereas Mycetoporinae forms a sister group relationship with Olisthaerinae. These results support the polyphyly of the Tachyporine Group of subfamilies consistent with several previous studies (e.g., [6,7,196]). Nevertheless, further study is needed to corroborate these hypotheses.
• Re-examination of fossil records of both Tachyporinae and Mycetoporinae dramatically changes the known evolutionary history of each taxon: Tachinusini (~ Upper Jurassic, but likely Middle Jurassic [51]), Vatesini (~ mid-Cretaceous), and Tachyporini (~ Upper Cretaceous). Deropini so far has no fossil record, but must have originated in the Late Jurassic, or earlier, in accordance with its sister tribe Tachinusini. In contrast, the origin of Mycetoporinae can be reliably traced back only to the Early Cretaceous.
• My backbone phylogeny of Tachyporinae may play an important role for evolutionary ecology or inventory surveys in the future. For example, semi-aquatic taxa are found only in the Deropini + Tachinusini clade, while myrmecophily and termitophily occur only in Vatesini and Tachyporini. Mycetoporinae species are frequently associated with fresh mushrooms. The clarification of morphological adaptations of these taxa would be an interesting and valuable subject for further study.