This art icle was downloaded by: [ 117.175.97.184] On: 26 March 2014, At : 03: 53 Publisher: Taylor & Francis I nform a Lt d Regist ered in England and Wales Regist ered Num ber: 1072954 Regist ered office: Mort im er House, 37- 41 Mort im er St reet , London W1T 3JH, UK Italian Journal of Zoology Publicat ion det ails, including inst ruct ions f or aut hors and subscript ion inf ormat ion: ht t p: / / www. t andf online. com/ loi/ t izo20 Delectona madreporica n. sp. (Porifera, Demospongiae) boring the corallites of some scleractinians from the Ligurian Sea Giorgio Bavest rello a , Barbara Calcinai a , Carlo Cerrano a & Michele Sarà a a Ist it ut o di Zoologia , Universit à di Genova , via Balbi 5, Genova, I‐16126, It aly Published online: 28 Jan 2009. To cite this article: Giorgio Bavest rello , Barbara Calcinai , Carlo Cerrano & Michele Sarà (1997) Delect ona madreporica n. sp. (Porif era, Demospongiae) boring t he corallit es of some scleract inians f rom t he Ligurian Sea, It alian Journal of Zoology, 64: 3, 273-277, DOI: 10. 1080/ 11250009709356208 To link to this article: ht t p: / / dx. doi. org/ 10. 1080/ 11250009709356208 PLEASE SCROLL DOWN FOR ARTI CLE Taylor & Francis m akes every effort t o ensure t he accuracy of all t he inform at ion ( t he “ Cont ent ” ) cont ained in t he publicat ions on our plat form . However, Taylor & Francis, our agent s, and our licensors m ake no represent at ions or warrant ies what soever as t o t he accuracy, com plet eness, or suit abilit y for any purpose of t he Cont ent . Any opinions and views expressed in t his publicat ion are t he opinions and views of t he aut hors, and are not t he views of or endorsed by Taylor & Francis. The accuracy of t he Cont ent should not be relied upon and should be independent ly verified wit h prim ary sources of inform at ion. 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(Porifera, Demospongiae) boring the corallites of some scleractinians from the Ligurian Sea GIORGIO BAVESTRELLO BARBARA CALCINAI CARLO CERRANO MICHELE SARÀ Downloaded by [117.175.97.184] at 03:53 26 March 2014 Istituto di Zoologia, Università di Genova, via Balbi 5, I-16126 Genova (Italy) INTRODUCTION Boring sponges have long been known because of the ecological impact they cause by riddling the limestone substrata they inhabit in most marine environments (Rützler, 1975). Stony corals, in particular, are infested by several species of clionids which play an important role in carbonate turnover in the coral reef system. Many ecological studies have been carried out on this subject in different tropical coral reefs. The damage to coral skeleton differs according to coral species and geographic location. In Caribbean corals over 90 of the excavations are due to clionids (Highsmith, 1981). Taxonomic studies on clionids have been carried out on the tropical coral reefs around the world (Annandale, 1915; Thomas, 1969; Pang 1973; Rützler, 1974). In the Mediterranean, some studies have been made on clionids boring precious red coral (Melone, 1965; Templado et al., 1986; Corriero et al., 1988; Maldonado, 1992, Bavestrello et al, 1996) describing 11 species belonging to the genera Cliona, Aka, Thoosa, Delectona, Alectona, and Spiroxya. Nevertheless, clionids living inside Mediterranean stony corals are almost unknown, with the exception of a study carried out by Barletta & Vighi (1968) comparing sponges boring the scleraxis of Corallium rubrum with those boring the corallites of Leptopsammia sp. and Caryophyllia sp. from different localities. These authors listed four species of sponges boring scleractinians: Cliona janitrix, ABSTRACT A new species of sponge, belonging to the genus Delectona, has been observed in the corallites of Leptopsammia pruvoti and Madracis pharensis living in semidark caves on the Portofino Promontory (Ligurian Sea). The species, here described as Delectona madreporica, has a spicular complement composed of rhabds, which are very irregular in shape and size and derived from fusiform amphiasters, by oxyasters derived from slender amphiasters and by toxiform, sometimes centrotylote, microxeas. The taxonomic position of this species is discussed. KEY WORDS: Taxonomy - Demosponges - Mediterranean Sea Boring activity. ACKNOWLEDGEMENTS The authors are indebted to Miss. Andreina Narcisi and Mr. Paolo Torre for their helpful assistance. This work was supported by the Italian Ministero dell'Università e della Ricerca Scientifica e Tecnológica, MURST 60 and 40 funds. (Received 28 January 1997 - Accepted 15 March 1997) C. sarai, A. labyrinthica and Thoosa sp. Differences in the faunistic composition between different localities were observed. In fact, along the Portofino Promontory the most common boring sponges are C. janitrix and A. labyrinthica (44 and 3 5 , respectively, of the observed colonies), while at S. Teresa di Gallura A. labyrinthica bores 74 of the corallites while the rest is bored by C. sarai. In addition to sponges of the genus Cliona, and Aka, Barletta & Vighi observed one species of Thoosa in 6 of the examined scleractinians from Portofino. During a study of the sponges boring the corallites of Leptopsammia pruvoti and Madracis pharensis along the Portofino Promontory, we observed in a semidark cave a new species of the rare genus Delectona: D. madreporae that is described here. MATERIALS AND METHODS The examined specimens were collected by diving at the rocky cliff of Paraggi (Portofino Promontory, Ligurian Sea). Sampling was conducted both on the exposed cliff and within a semidark cave 22 m deep. Two species of stony corals were recorded: Leptopsammia pruvoti and Madracis pharensis. The first species produces solitary, yellow corallites grouped in tufts and it is typical of the Mediterranean coralligenous assemblage living on rocky cliffs or caves (Zibrowius, 1980). M. pharensis forms small encrusting colonies in semi-dark caves (Zibrowius, 1980). The sponges were studied by opening the boring chambers by means of a scalpel, under the stereo microscope. The sponge tissue filling the chambers was dehydrated and mounted on slides to study the skeletal architecture. Spicules were obtained by boiling sponge 274 G. BAVESTRELLO, B. CALCINAI, C. CERRANO, M. SARA fragments in nitric acid. For SEM study, spicules slides were covered with gold-palladium and examined with a PHILIPS SEM 515. The type material of the new species has been deposited in the Museo di Storia Naturale of Genoa (MSNG). TAXONOMIC ACCOUNT According to the data reported by Barletta & Vighi (1968), the most common clionids in the two species of scleractinians are Cliona janitrix and A. labyrinthica but, while in the lighted, exposed cliff, these two species are the only ones present, in the semidark caves about 20 of the bored specimens both of Leptopsammia and Madracis contains a new species belonging to the genus Delectona described here. Family CLIONIDAE Gray, 1867 Downloaded by [117.175.97.184] at 03:53 26 March 2014 Genus Delectona De Laubenfels, 1936 Boring sponges without megascleres. The skeleton is a confused arrangement of thick rhabds covered by subsphaerical swellings, toxiform oxeas and slender amphiasters. Discs may be present. Type species Delectona higgini (Carter, 1880). Delectona madrepórica sp. n. Material examined Holotype: MSNG 48875 in a corallite of L. pruvoti collected at Paraggi (Ligurian Sea), 22 m depth, 30.05.95Paratype: MSNG 48876 in a colony of M. pharensis collected at Paraggi (Ligurian Sea), 22 m depth, 30.05.95. Description Excavations - the boring chambers (5-12 per specimens of coral) are subspherical or ovoid when two continuous chambers merge. They occupy the basal portion of corallites. Their size ranges from to 4.5 mm x 2 to 4 mm (4x3 mm mean size). The chambers are connected by one or two foramina from 0.5 to 1 mm wide. The chamber walls are etched by polygonal pits with an average diameter of 55.4 ± 6.3 um (Fig- la> b). Papillae are not visible on the surface of the stony corals or on the substratum around the corallites. The skeleton is mainly constituted by a confused arrangement of rhabds. Spiculation - a) rhabds, abundant, irregular in shape and with wide size range (10-50 x 3-10 urn; 28 x 6 urn mean size) (Fig. 2). Generally they are derived from fusiform amphiasters and are formed by a stout central axis, smooth or spiny with two verticils composed by several spiny outgrowths sometimes affecting the entire axis (Fig. 2a-e). This shape may present several transformations. In some spicules the two verticils are terminal and the spicule assumes a diplaster shape (Fig. 2f, g). In other cases (Fig. 2h, i), the original structure, made up of Fig. 1 - Delectona madrepórica pitting pattern in the boring chambers. Bars: a, 50 (im; b, 10 \im. Fig. 2 - Delectona madrepórica, SEM micrographs of spicules. a-i) rhabds of very variable shape. Generally, they show their derivations from fusiform amphiasters (a-e) sometimes reduced to displaster (f-g). In other cases, the amphiaster structure and the spicule are reduced to bent or straight axes covered by spines (h) or smooth knobs (i). 1-m) toxiform oxeas, with pointed ends and sometimes a central irregular swelling, n-o) oxyasters (derived from the slender, irregular amphiasters present in the other species of the genus). Bars: a-e, h, 10 \xm; f-g, i, 7 um; 1-m, 15 urn; n-o, 5 urn. Downloaded by [117.175.97.184] at 03:53 26 March 2014 ..M, 276 G. BAVESTRELLO, B. CALCINAI, C. CERRANO, M. SARÀ CONCLUSIVE REMARKS 3a), toxiform oxeas and peculiar amphiasters with eight or more capitate rays. Delectona ciconiae and D. alboransis show a very similar spicular complement. Both of them have typical rhabds of variable shape and size covered by four or five spiny knobs and deriving from nodulose amphiasters recalling those of Thoosa (Fig. 3b), slender irregular amphiasters, longer toxiform oxeas and rough discs. Megascleres (oxeas and subtylostyles) have been also described in D. alboransis. The presence of these megascleres is, for us, disputable because it is very common to find foreign spicules even embedded in the sponge tissue of boring species. In the examined material of D. ciconiae (numerous specimens from three localities) foreign megascleres (oxeas, tylostyles, subtylostyles) have often been observed. Boring chambers are, in fact, a particular microhabitat used as refuge for many species, that can be also confused with excavating sponges. Moreover, both Carter (1880) and Thomas (1972) who collected the type species of the genus (£>. higgini) have not observed any megascleres. If, as we suppose, the megascleres of D. alboransis are extraneous, this species becomes a synonymous of D. ciconiae. On the contrary, if the megascleres are really a component of the skeleton of D. alboransis a new genus should be erected for this species. The genus Delectona was erected by De Laubenfels (1936) on the basis of Alectona higgini, described by Carter (1880) as boring into the layers oí Melobesia from the Gulf of Manaar. In 1996 Bavestrello et al. (1966, November) described from the Alboran Sea, Elba Island and Bosa Marina D. ciconiae whereas Rosell (1996, December) described from the Alboran Sea D. alboransis. Delectona higgini has a spicular complement composed of rhabds covered by subspherical swellings (Fig. Delectona madrepórica differs from the other species of the genus in the smaller size and in the shape of its rhabds, which are derived from fusiform amphiasters similar to those of some species oi Alectona (Fig. 3c), and in the presence of oxyasters instead of slender amphiasters. The genus Delectona comprises, therefore, until now three species whose spicular features are summarized in Table I. The rhabds of the species of Delectona, similar to the amphiasters of Alectona and Thoosa and to spicules two distinct verticils, is completely lost as the bent axis may grow in length and be covered by spines (Fig. 2h). Other spicules are reduced to a stout, straight axis bearing smooth knobs (Fig. 2i). All these forms, probably, belong to a single spicular category and intermediate steps are always present; b) toxiform oxeas 50-65 um (60 Um mean size) x 0.5-1 um in size, with sharp ends and occasionally a central irregular swelling (Fig. 21, m); c) oxyasters (Fig. 2n, o) 15-18 |xm in diameter (17 um, mean size) composed by 5-7 rays 1-2 urn thick and 5-7 urn long; their surface is irregularly microspiny. Very little (about 5 (im) amphiasters have rarely been observed. Distribution and ecology Downloaded by [117.175.97.184] at 03:53 26 March 2014 Delectona madrepórica is a sciaphilous species living inside caves where it bores the corallites of Leptosammia pruvoti and Madracis pharensis, apparently without selective criteria. Etymology The species is named after its particular habitat. TABLE I - Spicular features of the three species of Delectona. Rhabds Oxeas Amphiasters oxyasters Discs D. higgini sausage-like, covered hair-like by subsphaerical (51 urn) swellings (21-85 x6-ll |im) slender, with two not present not present verticils of four or more rays (17-21 |xm) D. ciconiae derived from nodulose central swelling (62-104, 90 on average, amphiasters (18-63 x 7-10 um; 44 x 8 on x 1-2 (im) average) slender, irregular axis (31-36 x 1-2 \xm), rays 2-3 per verticils (10-16 x 1-2 |im) D. madrepórica derived from fusiform amphiasters (10-65 x 3-10 urn; 28 x 6 in average) oxyasters (15-18 toxiform, sometimes with a central swelling Um in diameter, (55-70, 60 on average, rays 5-7) x 0.5-1 urn) Bored substratum nodules of Melobesia sub-circolar or dead colonies of ovoid, rugate Corallium rubrum (13-21 x 5-13; 16 x 11 on average) not present corallites of Leptosammia pruvoti and Madracis pharensis DELECTONA MADREPÓRICA N. SP. 277 Downloaded by [117.175.97.184] at 03:53 26 March 2014 sometimes observed in some Cliona, (such as C. rhodensis) and generally called "spirasters" (Fig. 4), suggest a relationship among Delectona and these other genera, and consequently a systematic position within the Clionidae family. Like other clionid species boring precious red coral, D. madrepórica never bypasses the living tissue of the cnidarian with papillae of the aquiferous system. These are neither visible on the corallites, nor in the calcareous substratum close to the cnidarian. Fig. 3 - Comparison of commonest shapes of rhabds in (a) Delectona biggini, (b) D. ciconiae and (c) D. madrepórica . REFERENCES Annandale N., 1915 - Indian boring sponges of the family Clionidae. Rec. Indian Mus. (Calcutta), 11: 1-24. Barletta G., Vighi M., 1968 - Ricerche sul corallo rosso, V - Poriferi perforanti lo sclerasse di Corallium rubrum Lamarck.. Rend. Ist. Lombardo Sci. Lett., 102: 115-139. 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Tourtugas Lab., 30: 1-225. Gray J. E., 1867 - Notes on the arrangement of sponges, with the description of some new genera. Proc. zool. Soc. Lond., 492-558. Highsmith R. C, 1981 - Coral bioerosion at Enewetak: agents and dynamics. Int. rev. ges. Hydrobiol., 66: 335-375. Maldonado M., 1992 - Demosponges of the red coral bottoms from the Alboran Sea. J. nat. Hist., 26: 1131-1161. Fig. 4 - Comparison of diplasters-like rhabds of Delectona madrepórica and "spirasters" of Cliona rhodensis (from Rützler & Bromley, 1981; redrawn). Melone N., 1965 - I Poriferi associati a Corallium rubrum (L.) della Sardegna. Ann. Mus. civ. Stor. nat. Giacomo Doria, Genova, 75: 343-358. Pang R. K., 1973 - The systematics of some Jamaican excavating sponges (Porifera). Postilla, 161: 1-75. Rosell D., 1996 - A new diagnosis of the genus Delectona (Porifera, Demospongiae), with a description of à new species from Alboran Sea (western Mediterranean). Helgol. Meeresunters, 50: 425-432. Rützler K., 1974 - The burrowing sponges of Bermuda. Smithson. Contr. zool., 165: 1-32. Rützler K., 1975 - The role of burrowing sponges in bioerosion. Oecologia, 19: 203-216. Rützler K., Rieger G., 1973 - Sponge burrowing: fine structure of Cliona lampa penetrating calcareous substrata. Mar. Biol., 21: 144-162. Rützler K., Bromley R. G., 1981 - Cliona rhodensis, new species (Porifera: Hadromerida) from the Mediterranean. Proc. biol. Soc. Wash., 94: 1219-1225. Templado J., Garcia-Carrascosa M., Baratech L., Capaccioni R., Juan A., Lopez-Ibor A., Silvestre R., Massò C., 1986 - Estudio preliminar de la fauna asociada a los fondos coraligenos del mar de Alboran (SE de España). Bol. Inst. esp. Oceanog., 3: 93-104. Thomas P. A., 1969 - Boring sponges of the reefs of Gulf of Mannar and Palk Bay. Symposium on Corals and Coral reefs. Mar. Biol. Ass. India: 333-362. Zibrowius H. 1980 - Les Scléractiniaires de la Méditerranée et de l'Atlantique nord-oriental. Mem. Ist Ocenogr. 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