Aricidia (Acmira) Strelzov, 1973
Aricidea (Acmira) assimilis Tebble, 1959 sensu Strelzov, 1973*
Voucher specimens. Sea Lion: Station 44MFC (1 adult with antenna missing, 1 juvenile with long antenna present), Station 12MFA (specimen with regenerating antenna).
Diagnosis. Voucher 44MFC adult specimen, incomplete 53 segments long fragment, 8mm long and 0.9mm wide, colour in alcohol pale to dark yellow, often with a sort of rusty pigment in the anterior part of the body (both dorsally and ventrally). Prostomium is distinctly pear-shaped, with prominent oblique nuchal organs on posterior part of prostomium; eyes absent. Unpaired prostomial antenna very long (voucher 44MFC, juvenile, incomplete 2mm long and 0.1mm wide), extending to chaetiger 6 (at its longest), antenna easily lost, in many specimens antenna missing completely or regenerating and of variable length can be extremely short knob-like or extending past segment 1 somewhat arched (voucher 12MFA) .
Branchiae present from chaetiger 4, easily broken off, can be missing entirely, around ~20 pairs in adults (~14 pairs in juveniles), foliaceous extending into tips, anterior pairs just about meeting in the middle, branchiae becoming longer with 3 (of the last 5) pairs extremely long with bulbous base and very long thin tips, the very last one or two pairs extremely short.
Notopodial postchaetal lobes very small in prebranchial segments, large angular (elbow-shaped) in branchial region, becoming very thin and long (thread-like) in postbranchial region. Neuropodial lobes inconspicuous.
Notochaetae always long, dense capillaries. Neurochaetae, in addition to capillaries, distinct spines present from segment 23 in small (juvenile) specimen and 25 in adult, up to 7 per fascicle, appearing somewhat distally bidentate, occasionally with indistinct pubescence, often with short, thin arista arising from the convex side . Pygidium not observed.
Remarks. Important characters, such as antenna and branchiae easily lost in this species, several vouchers were used to show full set of characters of this species. Of the currently known species of Aricidea (Acmira) subgenus the FI specimens is most similar to Aricidea (Acmira) assimilis Tebble, 1959 in shape of prostomium and length of antenna. Tebbles description is severely lacking in detail. Branchiae are inadequately described to compare these structures and types and paratypes re-examined at NHM London were found to be in poor condition, with most branchiae missing. Importantly the type locality of A. (A.) assimillis is Mediterranean Sea (Israel). During his work on monograph of Paraonidae, Strelzov (1973) re-examined some of Tebbles specimens and additionally described material from the Pacific and South Georgia (SG), which he assigned to A. (A.) assimillis. The FI specimen agree well with the description given by Strelzov (1973) in shape of prostomium, length of antenna, however the shape and length of branchiae is not well described or pictured by Strelzov (1973). The SG specimens also agree with FI specimens in the form of their modified neurochaetae, although the heavy pubescence found in Strelzovs specimens has not been confirmed in FI specimens. We suggest that FI material (and likely Strelzovs SG material) represent a different species from A. (Acmira) assimilis found in Mediterranean. Additionally, great care should be taken when identifying these specimens, because branchiae and antennae can be easily lost, the specimen in various stages of damage can be found and could be misidentified (i. e. the length of antenna is considered an important taxonomic character in Aricidea, but in this material represent various re-generation stages.
