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.