Orbiniella

Blake, James A., 2017, Polychaeta Orbiniidae from Antarctica, the Southern Ocean, the Abyssal Pacific Ocean, and off South America, Zootaxa 4218 (1), pp. 1-145 : 118

“ Orbiniella ” branchiata ( Hartman, 1967)

Orbiniella branchiata Hartman, 1967: 165 –166, pl. 33; Rozbaczylo 1985:130.

Material examined. Drake Passage, Eltanin Sta. 9-740, 18 Sep 1963, 56.10°S, 66.32°W, 384–494 m, holotype (USNM 55533).

Description. Holotype incomplete, small, 4 mm long, 0.8 mm wide for 22 setigerous segments. Prostomium much wider than long, tapering anteriorly, rounded on anterior margin, Eyespots absent. Peristomium with three narrow asetigerous rings; separation of thorax and abdomen gradual, indistinct, occurring from setiger 14; branchiae from setiger 4, long at first, broad basally, tapering apically, continuing to posterior segments; noto- and neuropodial postsetal lobes simple, fingerlike; subpodial lobes or fringe lacking; notosetae including crenulated capillaries and furcate setae; neurosetae including thoracic and abdominal capillaries and abdominal aciculae.

Remarks. The holotype was well described by Hartman (1967). As a species of Orbiniella , O. branchiata is unusual in the presence of three achaetous peristomial rings, which should serve to readily differentiate the species from other orbiniids. However, given the small size of the holotype, the presence of branchiae, elongate postsetal lobes, and furcate setae, the species most likely represents a juvenile of another species in another genus.

Distribution. Drake Passage, 384– 494 m.