Dolichupis akangus, Simone & Cunha, 2012

Simone, Luiz Ricardo L. & Cunha, Carlo M., 2012, Taxonomic study on the molluscs collected in Marion-Dufresne expedition (MD 55) to SE Brazil: Xenophoridae, Cypraeoidea, mitriforms and Terebridae (Caenogastropoda), Zoosystema 34 (4), pp. 745-781 : 754-756

Dolichupis akangus n. sp.

( Fig. 4 A-D)

TYPE MATERIAL. — Holotype: Brazil, Espírito Santo, off Itaúnas, continental slope of Abrolhos, 18°56’S, 37°52’W, 85-105 m depth, MNHN 25218 ( Fig. 4 A-C) ( MD 55, stn DC 82, Bouchet, Leal & Métivier coll., 28. V.1987). Paratypes: same data as holotype, MNHN 25233, 1 shell, MZSP 104028, 2 shells. — Off Regência, 19°40’S, 37°48’W, 790-940 m depth, MNHN 25219, 3 shells, MZSP 104027, 2 shells (stn CB 77, 27. V.1987). — Off Itaúnas, 18°59’S, 37°48’W, 607-620 m depth, MNHN 25220, 6 shells, MZSP 104029, 4 shells (stn DC 73, 27. V.1987). — Off Conceição da Barra, 18°58’S, 37°49’W, 637 m depth, MNHN 25221, 1 shell ( Fig. 4D ) (stn CB 76, 27. V.1987).

TYPE LOCALITY. — Brazil, Espírito Santo, off Itaúnas, continental slope of Abrolhos, 18°56’S, 37°52’W, 85- 105 m depth ( MD 55, stn DC 82).

DISTRIBUTION. — Off Espírito Santo, Abrolhos continental slope.

E TYMOLOGY. — The specific epithet is derived from the word “akanga’i” in the Brazilian native Parintintin language, meaning rounded ( Betts 1981), an allusion to the rounded fashion of the shell.

DIAGNOSIS. — Shell of c. 5 mm, almost spherical; lacking dorsal groove; colour white. Sculpture c. 14 ribs, mostly continuous from side to side; c. 15 ribs in outer lip slightly protruding inside. Aperture in right side (far from central region).

DESCRIPTION

Shell of c. 5-6 mm; outline almost spherical, width c. 73% of length, height c. 64% of length. Colour pure white. Anterior and posterior canals similar from each other ( Fig. 4B, C ), slightly protruded, extending less than 10% of shell length. Spire entirely covered; apex not seen. Sculpture c. 14 narrow ribs, mostly perpendicular to longitudinal axis; interspaces about twice ribs width; most ribs running from side to side, entirely lacking dorsal groove; some shells with few ribs, mainly located in both, anterior and posterior regions, ending close to median line; 4-5 ribs, mainly in right side, ending in about half way between ventral region and median line ( Fig. 4A, B, D ); 4-5 ribs located on both canals positioned longitudinally, practically perpendicular to remaining ribs ( Fig. 4A, D ), those closer to median line touching with each other after distance c. 15% of shell length; remaining longitudinal ribs simply ending. Aperture narrow, arched only in both ends; comprising c. 10% of shell width and c. 80% of shell length; located on right third. Outer lip thick, with c. 26% of shell width, anterior and posterior regions extending beyond spire, posterior end more curved than anterior end ( Fig. 4C ); c. 20 transverse ribs, slightly protruding in inner edge, continuing as and similar to dorsal ribs; middle ribs perpendicular to longitudinal shell axis, gradually becoming oblique towards both canals. Siphonal and anal canals narrow, somewhat turned dorsally; siphonal canal more straight and located closer to median line; anal canal weakly more right located, turned to left. Inner lip lacking callus, fossular depression only in anterior half; c. 22 ribs weakly protruded inside aperture. Ribs in ventral region at left from aperture similar and continuous to dorsal ribs.

HABITAT. — Sandy-mud bottoms, 85-940 m depth.

MEASUREMENTS (in mm). — Holotype: 5.6 × 4.1; paratype MZSP 104028 (1): 5.2 × 3.8; paratype MNHN 25221 : 5.3 × 4.1.

Figures

FIG. 4. — Triviids:A, Dolichupis akangus n. sp., holotype MNHN 25218, dorsal view (L 5.6 mm);B, same, right view;C, same,apertural view; D, paratype MNHN 25221, dorsal view (L 5.3 mm); E, D. pingius n. sp., holotype, MNHN 25222, dorsal view (L 5.6 mm);F, same, right view; G, same, apertural view; H, paratype MZSP 104030, dorsal view (L 6.2 mm).