New species of Bairdioidea (Crustacea, Ostracoda) from the Southern Ocean and discussions on Bairdoppilata simplex (Brady, 1880),? Bairdoppilata labiata (Müller, 1908) and Bythopussella aculeata (Müller, 1908) * Author Brandão, Simone N. text Zootaxa 2008 1866 373 452 journal article 10.5281/zenodo.183820 287b1420-5c7c-4a05-ae95-e4c9121b51a6 1175­5326 183820 ? Bairdoppilata sp. 4 (Figs. 3.13, 4, 15.H–P) 1993 Bairdoppilata simplex , Hartmann : 211. Material . 1 RV, off Northeastern Antarctic Peninsula, RV Polarstern cruise PS ANT/ X/1 b, “1st station after O’Higgins”, 63°00.49’S , 57°09.45’W , 97m , date 22.12.1991 , ZMH K­ 35474. This RV was studied but not illustrated by Hartmann (1993) . Distribution . Off NW Antarctic Peninsula, Southern Ocean (Atlantic Sector), 97m . Measurements. RV, A L 0.84mm , H 0.48mm . Description. RV small, sub­hexagonal in lateral view, anterior more broadly rounded than posterior, slightly caudate, dorsal margin tri­segmented. Valve surface smooth. Normal pore canals not very numerous, with rim, sensilla long to very long. Fringes present on anterior margin and 10 denticles present on posterior margin. Calcified inner lamella very broad. Hinge anterior and posterior elements without denticles and sockets. Nine adductor muscle scars present, eight of them positioned in a circle surrounding the ninth scar. Remarks.? Bairdoppilata sp. 4 differs from B. simplex , because the first species presents: (1) the much smaller adult size; (2) longer carapace sensilla; (3) anterior and posterior elements of the hinge lacking denticles (instead of presenting denticulation); (4) conspicuous anteroventral convexity (not to be confounded with the anteroventral concavity present in many bairdioid RV); (5) denticulate posterior margin ( Fig. 15 .H–P).