Aglaophamus cf. peruana (Hartman, 1940)

Aglaophamus Kinberg, 1865

Aglaophamus cf. peruana Hartman, 1940

Vouchers. VINSON WEST: station 2 MFB; LOLIGO: station L14FA.

Diagnosis. Medium sized species represented by two complete (even if fragmented) specimens; 26mm long and 2.2mm wide for 65 chaetigers and 41mm long and 3mm wide for 75 chaetigers.

Prostomium subspherical, about as wide as long, with a V-shaped posterior margin, extending over the first chaetiger; a pair of nuchal organs clearly visible near the posterior corners of prostomium; a pair of conical antennae in the anterior corners of the prostomium and a pair of palps inserted posteriorly on ventrum the prostomium. Proboscis not everted. Inter-ramal cirri involute; from chaetiger 3 where rudimentary (easily overlooked, revealed by Shirlastain); slender throughout, progressively increasing in size up to mid body then decreasing in size posteriorly, eventually absent from the last 5 chaetigers. Parapodia biramous; complex with enlarged foliose postchaetal lobes in both rami (refer to the image for details). Dorsal cirri small, conical in chaetiger 1; from chaetiger 2 foliose, round, distally abruptly produced into shapely, slender tip; increasing in size till mid body then decreasing in size posteriorly, becoming very small and assuming nearly conical shape in the last 5 chaetigers. Ventral cirri particularly well developed in chaetiger 1, where bulbous with wide base and slender distally; well developed in other chaetigers, assuming more slender skittle-shaped to cirriform form; becoming very small digiform in posterior chaetigers. Preacicular chaetae cross-barred; postacicular chaetae spinulose along most of its shaft and single aciculae light yellow in colour, similar throughout the body length. Pygidium as terminal, blunt conical lobe.

Remarks. Specimens assigned here to Aglaophamus cf. peruana agree with Hartmans (1940) species particularly in that tiny branchiae detected from chaetiger 3 and both specimens posses various enlarged lobes and foliose dorsal cirrus. There are possibly some differences in the shapes of various lobes (Hartmans description is rather brief, but accompanied by drawings) and direct comparison with the holotype would be necessary to determine this. Falkland Islands specimen in fact show similarity to two other species with enlarged foliose lobes known from the region - Aglaophamus trissophyllus and Aglaophamus foliosus. Aglaophamus trissophyllus (known for reaching very large size) has a confused taxonomic history. It was originally described by Grube (1877) from the Kerguelen Is, while Hartman (1967) described A. ornatus from the deep Bransfield Straits, which was later synonimized with A. trissophyllus. Hartman (1967) also described another similar species as Aglaophamus foliosus, from deep-water (S. Sandwich Is. in 1482m and Cape Horn 1906-2013m) and questionably from Falkland Is. in 578m. Examination of non-type material of A. trissophyllus collected from Kerguelen Is. (type locality of Grubes A. trissophyllus) available at NHM collection was undertaken to draw comparisons with Falkland Is. specimens and A. folisosus (based on Hartmans description and images). These observations were summarized in table below; for images of parapodia refer to comparative figure. Further work, accompanied by molecular studies will be necessary to fully resolve the status of Falkland Islands specimens collected here.

Summary of some characters of Aglaophamus from Falkland Islands (this study) and most similar species reported from the region.