New species, misidentifications and problematic taxonomy of some Atlantic South American marine mollusks: a review Simone, Luiz Ricardo L. Papéis Avulsos de Zoologia 2024 2024-08-09 64 1 104 7NYQY Iredale, 1931 Iredale 1931 [1013,1279,1594,1619] Bivalvia Nuculidae Ennucula Animalia Nuculida 57 58 Mollusca genus   ( Fig. 39) https://zoobank.org/ D91C55F5-3B23-4C4A-B4A5-AD0A130D1826  Types:  Holotype MZSP 166732, shell. Paratypes: MZSP 166733, 1 shell, MZSP 166629, 12 shells, 58 valves, MNRJ, 2 shells + 3 valves, MNHN-IM-2000-39810, 1 shell + 9 valves, all from type locality.     Typelocality: BRAZIL.  Espírito Santo; ItaÚnas, off, Abrolhos slope, 19°40.6′S 37°48.1′W,  790-940 m[ MD55sta. CB77,  27.v.1987].   Diagnosis:Species from off SE Brazilof ~ 5 mm, with almost central umbo. Ligament almost perpendicular. Hinge with 11-12 anterior and 8-9 posterior teeth.   Description:Shell of ~ 5 mm; outline rounded; ~1.2 times longer than heigh; walls slightly thin. Umbo relatively blunt, slightly prominent; almost central slightly dislocated anteriorly, with umbonal angulation of ~110°. Anterior and posterior umbonal edges almost symmetrical, both convex, flattened in edges, almost wing-like; posterior edge slightly shorter and more vertical; anterior edge longer and slightly more convex; ventral edge widely rounded ( Fig. 39A-B, D-G, J-M) with weak, blunt posterior beak. Very weak, oblique anterior carina. Maximum inflation ~50% of length ( Fig. 39C). outer surface glossy, shining; sculpture commarginal, narrow, uniform cords,from umbo up to edges ( Fig.39A,B,D,E);interspaces equivalent to each cord width. Periostracum heavy, brown ( Fig. 39A-E); when absent, color white ( Fig. 39J, L). Ligament with inner portion thick, guttiform, restricted to sub-umbonal region, angulation ~30° in relation to dorso-ventral axis ( Fig. 39F, G-I, K, M). Hinge occupying entire dorsal edge ( Fig. 39F, G, K, M), thicker regions occupying ~15% of shell height; teeth reaching ligamental area; from this region both anterior and posterior series of teeth gradually growing towards edges, becoming wider in subterminal region in both sides, mainly in anterior set, with very broad subterminal stretch; 11-12 teeth in slightly curved, longer anterior set; 8-9 teeth in slightly shorter, also weakly curved posterior set. Both set of teeth with very tall, triangular, pointed teeth ( Fig. 39H, I). Both adductor muscle scars rounded, located ventrally to both ends of hinge, anterior scar slightly larger ( Fig. 39G); pallial line weakly visible parallel to ventral edge ( Fig. 39G, K).   Etymology:The specific epithet is based on the Guarani language word ipepo,meaning wing, an allusion to the expansions in both sides of the umbo.   Distribution:Off Espírito Santo, continental slope of Abrolhos. [879,1217,1754,1779] MZSP 57 58 MZSP 166732 1 holotype [794,1256,1914,1939] Brazil Espirito Santo 57 58 1 Espirito Santo holotype 1987-05-27 MD, CB Brazil 865 -19.676666 127 -37.801666 57 58 MD55, CB77 1 Espirito Santo holotype