Puncturella volcano, 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 : 459

Puncturella volcano new species

Figures 116–120

Types. Holotype MNHN 25328.

Type locality. Brazil. Espírito Santo; off Itaúnas, continental slope of Abrolhos, 18°59’S 37°48’W, 607–620 m (MD55 sta. DC73; Bouchet, Leal & Métivier col, 27/v/1987).

Diagnosis. Slightly curved posteriorly. Height ca. 35% of length. Outer surface sculptured by weak irregular, radial, low lines, sometimes coalescing, ca. 70 (close to aperture). Foramen shorter than half shell height.

Description. Shell size ca. 4 mm; high-conical, slightly arched posteriorly ( Fig. 117 ); height ca. 35% of length. White, translucent. Protoconch lost. Foramen terminal, oval, width 41% of length; turned dorsally; 2% of aperture area; edges rather irregular ( Figs 116, 120 ). Teleoconch widening towards aperture; total shell angle ca. 110°. Sculpture almost smooth, except for weak sculpture of irregular radial lines ( Figs 116–117 ), ca. 70 close to aperture, arranged in mosaic of coalescing, divergent lines ( Fig. 117 ); mosaic crowded towards apex, retaining the same number of radial lines from dorsal to ventral; lines surrounded by smooth interspaces as wide as lines. Aperture slightly concave, elliptical, width 74% of length; edges irregular. Inner surface smooth, glossy ( Figs 118–119 ). Septum slightly curved (concavity posterior), ca. 1/2 of shell height; about as high as wide, ventral edge straight, with ca. 30% of aperture width; narrowing up to posterior edge of foramen, forming posterior, ventral floor of foramen ( Fig. 120 ).

Measurements (in mm). Holotype: 3.8 by 1.3.

Distribution. Only known from type locality.

Habitat. Sandy bottoms, 607–620 m (dead specimen).

Material examined. Holotype.

Etymology. The specific epithet is derived from the English word volcano , an allusion to the appearance of the shell.

Remarks. The generic attribution of P. volcano is based on the loss of the protoconch, and by the rounded shape of the fissure (following definition by Farfante 1947). An attribution to the genus Fissurisepta Seguenza, 1862 to P. v o l c a no is not plausible because it is lower, more curved backwards at the apex, the foramen is wider and more elongated, and the sculpture is not so developed.

The low shell profile and the weak shell sculpture distinguish this species from any other congeneric species in the Atlantic, which have stronger radial ribs or threads. The species differs from P. sportella Watson, 1883 , in lacking radial pits or ribs, and by the shorter septum.

Figures

FIGURES 116 – 120: Puncturella volcano n. sp. Holotype MNHN 25328 (L 3.8 mm). Fig. 116: dorsal view. Fig. 117: right view. Fig. 118: ventral-slightly right view. Fig. 119: ventral view. Fig. 120: detail of apex, dorsal view (side = 1 mm). FIGURES 121 – 125: Rimula leptarcis n. sp. holotype MNHN 25329 (L 4.4 mm). Fig. 121: dorsal view. Fig. 122: left view. Fig. 123: ventral view. Fig. 124: right view. Fig. 125: detail of fissure, dorsal view (side = 1.8 mm). FIGURES 126 – 129: Zeidora pussa n. sp., holotype MNHN 25320 (L 2.7 mm). Fig. 126: dorsal view. Fig. 127: ventral view. Fig. 128: ventralslightly right view. Fig. 129: right view.