Cornisepta uirapa, Simone, Luiz Ricardo L. & Cunha, Carlo M., 2014

Simone, Luiz Ricardo L. & Cunha, Carlo M., 2014, Taxonomical study on the mollusks collected in Marion-Dufresne (MD 55) and other expeditions to SE Brazil: the Fissurellidae (Mollusca, Vetigastropoda), Zootaxa 3835 (4), pp. 437-468 : 439-441

Cornisepta uirapa new species

( Figures 1–5 )

Types. Holotype MNHN 25281.

Type locality. Brazil. Espírito Santo; off Regência, continental slope of Abrolhos, 19°40’S 37°48’W, 790–940 m depth (MD55, sta. CB77; Bouchet, Leal & Métivier col, 27/v/1987).

Diagnosis. Slightly curved posteriorly. Height ca. 87% of length. Sculptured by uniformly distributed small pustules arranged in alternate rows, ca. 80 per row (close to aperture).

Description. Shell height ca. 5 mm; highly conical, slightly arched posteriorly ( Figs 1, 2 ); height 87% of length. White, translucent. Apex about equidistant from anterior and posterior margins. Protoconch no longer present. Foramen terminal, elliptical, width ca. 60% of length; turned dorsal; occupying ca. 2% of aperture area in dorsal view; edges rather irregular ( Fig. 4 ). Shell increasing in width towards aperture uniformly, gradual; main axis almost vertical; apical angle ca. 35°, total shell angle ca. 40°. Outer sculpture uniform rows of small pustules ( Figs 1–3 ), ca. 80 per row close to aperture, slightly intercalated in adjacent rows; this mosaic somewhat regular towards apex, pustules increasing in number from dorsal to ventral; each pustule surrounded by smooth area equivalent to 3 times its width. Aperture in same plane (straight), elliptical, width approximately 72% of length; edges slightly irregular. Inner surface smooth, glossy ( Fig. 5 ). Septum ca. 1/2 shell height; ca. 3 times higher than wide, ventral edge shallowly concave, almost straight, ca. 1/2 of aperture width; gradually narrowing up to posterior edge of fissure.

Measurements. Holotype: 4.7 by 5.3 mm.

Distribution. Only known from type locality.

Habitat. Sandy mud bottoms, 790–940 m depth (dead specimen).

Material examined. Holotype.

Etymology. The specific epithet is derived from the Tupy native language uirapa , meaning arc, arched, in allusion to the arched shape of the shell.

Figures

FIGURES 1 – 5: Cornisepta uirapa n. sp. holotype MNHN 25281 (L 4.7 mm). Fig. 1: left-slightly ventral view. Fig. 2: leftslightly dorsal view. Fig. 3: anterior view. Fig. 4: dorsal view. Fig. 5: ventral view. FIGURES 6 – 16: Cornisepta arrepiata n. sp. Fig. 6: holotype MNHN 25282 (L 3.4 mm), right view. Fig. 7: same, dorsal view. Fig. 8: same, left view. Fig. 9: same, ventral-slightly left view. Fig. 10: same, anterior view. Fig. 11: paratype MNHN 25283 (L 3.3 mm) right view. Fig. 12: paratype, MZSP 102943 in SEM, right view (L 2.1 mm). Fig. 13: same, dorsal view. Fig. 14: same, ventral view. Fig. 15: paratype MNHN 25283, left view (L 2.1 mm). Fig. 16: same as Fig. 12, detail of outer surface in middle level (scale 0.2 mm). FIGURES 17 – 18: Cornisepta aninga n. sp. in SEM. Fig. 17: paratype MZSP 102942, detail of outer surface in middle region (scale 0.2 mm). Fig. 18: same, ventral-slightly left view (L 2.8 mm).