Profundisepta denudata, 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 : 457

Profundisepta denudata new species

Figures 109–115

Types. Holotype MZSP 105507. Paratypes: MZSP 105508, 4 shells from type locality.

Type locality. Brazil. São Paulo; continental slope off Ubatuba, 24°12’S 40°23’W, 3049 m (R/V W. Besnard, PI, 01/vi/1971, A. Birman leg.).

Diagnosis. Height ca. 80% of length. Outer surface slightly sculptured by ca. 120 faint radial cords, and concentric, delicate undulations. Protoconch smooth, glossy.

Description. Shell size ca. 3 mm; broadly conical; slightly arched posteriorly (Figs 110, 114); height ca. 80% of length. White, translucent, light beige apex (Figs 111, 115). Protoconch white, of 1.5 rounded whorls (Figs 114, 115); situated on right (Figs 109, 111), forming posterior apex of foramen; smooth, glossy; size 320 µm. Foramen subterminal, diamond-shaped, width ca. 50% of length; dorsally located – slightly turned anteriorly; ca. 10% of aperture area; edges rather irregular (Figs 109, 111). Teleoconch conical; angle ca. 55°. Sculpture weak; minute, thin mosaic of small pustules aligned in radial rows (Figs 110, 114), ca. 120 rows of pustules close to aperture, secondary cords (with about half shell height) intercalated between primary alignments; distance of neighboring pustule on the rows approximately half of the width of the pustule; interspaces between rows as wide as rows. Commarginal undulations distinct (Figs 109–112). Aperture planar (Figs 110, 114), elliptical, width ca. 85% of length; edges somewhat regular. Inner surface smooth, glossy (Figs 112, 113). Septum ca. 50% of shell height (Fig. 115); about as tall as wide; ventral edge slightly concave, 42% of aperture width; gradually narrowing to posterior edge of foramen, constituting posterior and ventral floor of foramen (Fig. 111).

Measurements (in mm). Holotype: 3.0 by 2.2; paratype MZSP 105508: #1, 2.8 by 2.7, 2#, 3.1 by 3.3.

Distribution. Continental slope off São Paulo, Brazil.

Habitat. ca. 3000 m (dead specimens).

Material examined. Types.

Etymology. The specific epithet is from Latin denudo, denudatus, meaning bare, uncovered, an allusion to the outer surface of shell lacking strong radial sculpture.

Remarks. Profundisepta denudata differs from P. profundi ( Jeffreys, 1877) ( McLean & Geiger, 1998: figs 3A–C), and from other congeneric species from North Atlantic [ P. alicei (Dautzenberg & Fischer, 1897) ; P. bo r ro i ( Farfante, 1947); P. sportella ( Watson, 1883) ] ( McLean & Geiger 1998), by the weak radial sculpture, the concentric undulations, and in being slender; the remaining shell features are similar. Profundisepta denudata differs from P. alicei ( McLean & Geiger 1998: figs 3H–I), from the Azores and the Iberian-Moroccan Gulf, in being wider, having weaker radial sculpture, by the blunt shape of the posterior edge of foramen, and by the larger protoconch.