Cranopsis apostrema, 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 : 448

Cranopsis apostrema new species

Figures 56–65

Types. Holotype MNHN 25300. Paratypes: MNHN 25301, 25 shells, MZSP 105509, 10 shells, MNRJ 25961, 4 shells; all from type locality. Brazil. Espírito Santo; continental slope of Abrolhos (MD55; Bouchet, Leal & Métivier col.; 27/v/1987); off Itaúnas, 18°59’S 37°48’W, 607–620 m, MNHN 25302, 3 shells (sta. DC73), 18°58’S 37°48’W, 682 m, MNHN 25303, 1 shell (sta. SY74); off Regência, 19°40’S 37°48’W, 790–940 m, MNHN 25304, 1 shell (sta. CB77). Rio de Janeiro; Campos Basin, 22°42’33.8”S 40°40’84.2”W, 110–120 m, MNRJ 17234, 1 shell (19/ix/2009).

Type locality. Brazil. Espírito Santo; off Itaúnas, continental slope of Abrolhos, 18°59’S 37°50’W, 295 m (MD55 sta. DC75; Bouchet, Leal & Métivier col., 27/v/1987).

Diagnosis. Apex curved posteriorly, located in middle level in profile. Height ca. 45% of length; width 66% of length. Sculptured by 53 radial cords, with pustules. Foramen flanked by low edges; located high on shell.

Description. Shell size ca. 5 mm; bluntly conical; height ca. 45% of length. Pure white. Protoconch of 1.5 rounded whorls (Fig. 60, 65); situated on right (Figs 57, 59); smooth, glossy; size 240 µm. Foramen cuneiform (pointed anteriorly), width 13% of length; located dorsally, preceding anterior slope; ca. 6% of shell width, ca. 25% of shell length; edges irregular (Figs 56, 61, 63). Groove anterior to fissure very narrow; flanked by cords of similar strength as neighbor cords. Beak curved dorso-posteriorly, located anterior to posterior 1/3 of shell length (in dorsal view), in middle of shell height in profile; teleoconch of one whorl, overall angle in lateral view ca. 110° (Figs 57, 59, 62, 64). Sculpture of ca. 53 (range 50–55) narrow primary radial cords (Figs 56–57, 59–64), with small pustules; gradually increasing in strength towards aperture; in ventral half secondary cords gradually appearing; each pustule separated from neighboring pustules in line by space ca.1/2 of its width; interspaces ca. twice as wide as cord; ca. 60 pustules along threads close to median line. Selenizone short, narrower than foramen; edges simple, low; smooth internally (Figs 56, 61, 63). Aperture planar (Figs 57, 59, 64) to slightly concave ( Fig. 62 ); outline elliptical, width approximately 66% of length; edges smooth. Inner surface smooth, glossy (Fig. 58). Septum ca. 40% of shell height; twice as high as wide, ventral edge slightly concave, ca. 25% of aperture width; gradually narrowing up to posterior edge of fissure.

Measurements (in mm). Holotype: 4.8 by 2.5; Paratype MZSP 105509#1: 4.8 by 2.5 ( Figs 61–62 ).

Distribution. Continental slope off Espírito Santo to Rio de Janeiro, Brazil.

Habitat. Sandy mud bottoms, 110–940 m (dead specimens).

Material examined. Types.

Etymology. The specific epithet is derived from the Greek, apo, meaning separate, and extrem, related to strike; an allusion to delicate radial sculpture of the shell.

Figures

FIGURES 61 – 65: Cranopsis apostrema n. sp. Fig. 61: paratype MZSP 105509 (L 4.8 mm), dorsal view. Fig. 62: same, left view. Fig. 63: same station, other specimen in SEM, dorsal view (L 4.4 mm). Fig. 64: same, right view. Fig. 65: same, detail of apical region (right side = 1 mm). FIGURES 66 – 75: Cranopsis alaris n. sp. Fig. 66: holotype MNHN 25305 (L 3.3 mm), dorsal view. Fig. 67: same, right view. Fig. 68: same, left view. Fig. 69: same, ventral-slightly right view. Fig. 70: paratype MZSP 105512 (L 2.7 mm), dorsal view. Fig. 71: same, right view. Fig. 72: same, detail of apical region, SEM, right view, scale = 50 µm. Fig. 73: same, SEM, right view. Fig. 74: same, dorsal-slightly right view. Fig. 75: same, ventral view.