Polynoinae Kinberg, 1856
Austrolaenilla Bergström, 1916
Austrolaenilla cf. antarctica Bergström, 1916
Voucher. Sea Lion: station 8MFA.
Diagnosis. Voucher is large, robust, complete (but in two fragments) specimen, anterior and posterior fragments is 20 and 17mm long respectively and 11mm wide (including parapodia) for 35 chaetigers; body dorsally purple; two narrow, white, ciliated horizontal lines on each segment.
Prostomium bilobed, rounded (about as wide as long), with very small (but discernible) cephalic peaks. Palps, smooth, long tapering into very slender tips. Three antennae present; ceratophore of median antenna large, with pigmentation, arising medially on prostomium; lateral antennae inserted ventrally; styles of all antenna very long and slender, covered by thin, elongated, distally slightly expanded papillae. Two pairs of very small, subdermal eyes in quadrate arrangement, situated laterally (not easily visible in dorsal view) near anterior and near posterior margins of prostomium.
Tentacular segment with few notochaetae; two pairs of tentacular cirri, their cirrophores large and cylindrical, their styles similar to those of antennae - thin, papillated, but shorter. Second segment with biramous parapodia, chaetae, a pair of elytra and ventrally with very long ventral cirrus (much longer than in subsequent segments) inserted basally and papillated (similar to antennae and tentacular cirri).
Elytra present, 15 pairs of elytrophore (35 chaetiger long specimen) on chaetigers 2, 4, 5, 7, 9, 11, 13, 15, 17, 19, 22, 25, 28, 31 and 34. Elytra large, milky, with entire surface covered densely by sharply conical microtubercles; margin appear smooth but under high magnification, few scattered, thin, elongated papillae observed.
Parapodia distinctly biramous; with notopodia much smaller than neuropodia; both rami with single, long acicula, extending into very long, thin acicular processes. Cirrigerous segments (those not carrying elytra) with large, broad, conical dorsal tubercule inserted at the same level as elytrophores of elytra-carrying segments; cirrophores of dorsally cirri very prominent, long cylindrical, inserted medially on notopodia (near fascicle of notochaetae), style of dorsal cirri very long slender, papillated similar to antennae and tentacular cirri. Ventral cirri, from chatiger 3, shortest of all appeandages, but still of considerable length, approaching the acicular tip; slender smooth; inserted medially on neuropodia. On ventrum, small digiform nephridial papilla detected from chaetiger 5.
Notochaetae numerous, of varying lengths, stout with distinct rows of spines and blunt tips, straw-coloured. Upper and middle neurochaetae strait, slender, very long, with rows of spines subdistally, tips of neurochaetae unidentate and hirsute; lower neurochaetae similar to upper and middle neurochaetae, but shorter, distally bent; with distinct rows of spines and also hirsute.
Pygidium with pair of very long, very slender, sparsely papillated lateral cirri.
Remarks. Genus Austrolaenilla is well represented in Southern Ocean, with A. antarctica being the type species of the genus described by Bergström (1916) from South Georgia. Currently 4 to 5 species are reported from the Southern Ocean (A. fulgens has been considered subspecies of A. antarctica). It is evident from Hartman (1964) that species have been confused in the past as specimens of Monro (1930) and of Fauvel (1936) are different species, which in turn reflects the variation reported by Bergström (1916) who recognised more than one morphotypes in his original description (his description appears to be based on syntypes). Falkland Island specimen agrees well with Bergströms (1916) type 4, which he described as very large (over 50mm long), with faint small eyes and elytral surface covered entirely by microtubercles (as oppose to type 2, which was smaller, less than 20mm long, well developed eyes with anterior pair dorsolaterally, microtubercules limited to small patch on elytra). A. hastulifera (Pruvot in Fauvel, 1936) would appear also to agree with the diagnosis of type 4. Recent molecular work also suggested that A. antarctica may represent species complex (Neal et al., 2014) and taxonomic revision of Austrolaenilla species from the Southern Ocean is needed. Juveniles of this species are commonly encountered in benthopelagic samples and were previously considered to be Herdmanella gracilis (see Neal et al., 2014 for details).