Prionospio Malmgren, 1867
Prionospio sp.
Voucher. Sea Lion: Station 38MFC
Diagnosis. Voucher is the only specimen collected in this study. Incomplete, small and slender specimen with 20 chaetigers, 2.2mm long and 0.15mm wide.
Prostomium anteriorly rounded, posteriorly extending to the end of chaetiger 1 as a short, blunt caruncle; eyes absent. Peristomium partially fused to chaetiger 1, not pronounced into lateral wings. Branchiae all missing, but small stumps (now lost) initially observed at least on chaetigers 2 and 3 (on one side only). Notopodial lamellae largest on chaetigers 2-4, triangular to leaf shaped with dorsal tip most pronounced in lamellae of chaetiger 3 and 4; corresponding neuropodial lamellae also largest in comparison to other chaetigers, oval. Very prominent dorsal crests in chaetigers 5-7, less prominent dorsal crests continue to chaetiger 12. Single, stout, granulated at the tip, sabre chaeta present in neuropodia from chaetiger 9; multidentate (main fang plus 4 smaller teeth observed in lateral view) hooded hooks present from chaetiger 10, up to 4 per fascicle; notopodial hooks not observed in 20 chaetigers long fragment; other chaetae capillaries. Pygidium unknown.
Remarks. The presence of small branchial stumps (initially observed at least on chaetigers 2 and 3, but now lost due to damage during the examination), the shape of prostomium and the form and distribution of neuropodial hooded hooks make this specimen consistent with genus Prionospio Malmgren, 1867. The distribution and form of branchiae is an important diagnostic character in this genus therefore a better specimen, with full branchial set is needed to fully diagnose this species. The particularly prominent dorsal crests on chaetigers 5-7 make this species easily recognisable from other spionid species collected from Falkland Islands.
