Scalibregma Rathke, 1843
Scalibregmatidae sp. 1
Voucher: VINSON WEST: station 1MFA.
Diagnosis. A small sized species, body elongate, anterior part slightly expanded, gradually tapering posteriorly; voucher specimen incomplete, with 14 chaetigers, 2mm long and 0.5mm wide. Colour light yellow, without pigmentation; without staining pattern (using Shirla-stain).
Body surface with the annulation formed by rows of quadrate cells, these moderately developed, more or less quadrate; segments tri- to quadriannulate. Ventral midline from chaetiger 2 with epidermal pads present until the end of fragment. Prostomium with very elongated processes or horns; positioned anteriorly giving the prostomium V-shaped appearance; posterior margin of prostomium visible dorsally; eyes absent. Proboscis partially everted, concealing the nature of peristomium and anteriormost segments ventrally.
Arborescent (=dendritically) branched branchiae present on chaetigers 2‒5 posterior to notochaetae. Parapodia biramous, reduced, inconspicuous in 14 chaetigers. Dorsal and ventral cirri not developed on 14 chaetigers present; uknown in posterior chaetigers.
All chaetigers with noto- and neuropodial fascicles of slender capillaries; in anterior region arranged into 2 rows, with chaetae of posterior row longest; capillaries of middle and posterior chaetigers arranged in 1‒2 rows. Lyrate chaetae present from chaetiger 2; each lyrate chaeta with unequal tynes with the longer tyne tapering to very slender filamentous tip; bristles on inner margins very short. Abdomen and pygidium uknown.
Remarks. The lack of midposterior and posterior segments due to incompleteness of the specimens prevents conclusive generic assignment of this specimen (the development of dorsal and ventral cirri in those segments is an important taxonomic character). Given the small size of the specimen, we cannot exclude that it may be juvenile. The distinct form of its prostomium distinguishes this specimen from other scalibregmatid material collected form Falkland Islands in this study.
