Sigalionidae sp. 2
Vouchers. VINSON WEST: station 4MFA and HERO: station 1 MFA.
Diagnosis. Both vouchers incomplete, the better preserved voucher (VINSON WEST 4MFA) 2.5 mm long, 0.8 mm wide (including parapodia) for 15 segments. Pharynx not extended. All elytra missing.
Prostomium oval, wider than long, with stout cylindrical ceratophore of median antenna bearing small lateral auricles, style missing; lateral antennae(?) very short lobes. Tentacular parapodium with single aciculum and bundles of extremely long, slender capillary chaetae; tentacular cirri with distinct cirrophores; styles slender tapering, of unequal length with dorsal tentacular cirri about 1/3 the length of ventral ones. Eyes absent. Palps long, extending to about segment 10, very slender, tapering.
Segment 2 with inflated elytrophores. Segment with pair of short bulbous cirrophores (?); styles missing (?). No branchiae observed. No parapodial ctenidia observed, but ventral ctenidia observed from about chaetiger 13. Parapodia distinctly biramous; stylodes absent.
Notopodia only slightly smaller than neuropodia, long, cylindrical; with distinct supraacicular process - short, rounded, blunt. Neuropodia long, cylindrical. Ventral cirri of 2nd segment inserted basally on neuropodium, longer than in subsequent segments (almost reaching tip of neuropodium); on other segments inserted medially, slender, elongated (but not reaching the tip of neuropodia). Distinct ventral ctenidia observed from chaetiger 13.
Notochaetae numerous of varying length, all finely spinous on one side, some slightly thicker than others. Neurochaetae very distinct; all of the same type, stout, compound, with blades of varying lengths; blades flattened, with widely spaced serration on one side, the other side undulating; distally with blunt, rounded tips.
Remarks. Vouchers lack elytra, therefore their generic assignment cannot be confirmed. Species is characterised by very distinct neurochaetae, which distinguish this species from other Sigalionidae reported here from Falkland Islands as well as from those known from wider region. Given very small size of the specimen we cannot exclude it is a juvenile form. At present we assign these to morphospecies Sigalionidae sp. 2.