Cranopsis canopa, 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 : 449-450

Cranopsis canopa new species

Figures 76–83

Types. Holotype MZSP 107718. Paratypes: MNHN 25309, 5 shells, MNRJ 30825, 2 shells, MZSP 94183, 11 shells, MZSP 90281, 24 shells, UF Mollusca 451489, 2 shells, USNM 1207437, 2 shells; all from type locality.

Type locality. Brazil. Ceará; off Fortaleza, Canopus bank, 2°12’43”S 38°18’52”W, 250 m (Coltro col., viii/ 2005).

Diagnosis. Apex curved ventrally, posterior-located. Height 43% of length; width 68% of length. Sculpted by ca. 70 radial, low cords, with transverse folds; interspaces minute. Foramen flanked by low edges; located dorsoanteriorly.

Description. Shell size ca. 3.5 mm; low, flattened; height 43% of length. Pure white. Protoconch of 1.5 rounded whorls ( Fig. 77 ); situated on right; smooth, glossy; ca. 140 µm. Foramen cuneiform (pointed anteriorly), width 13% of length; located dorso-anteriorly, at top of anterior slope; ca. 5% of shell width, 34% of shell length; edges rather irregular ( Figs 76, 78–80 ). Groove anterior to foramen very narrow; flanked by cords similar in width to neighbor primary cords; length ca. 50% of shell height; some specimens with both sides of anterior end not aligned ( Fig. 76 ). Shell profile low, rounded, apex curved ventrally, as low arc with center on middle point of ventral surface, apex located ca. 5% of shell length anterior to posterior end, in profile apex located between middle ventral thirds of shell height; teleoconch of almost one whorl; profile highly curved ( Figs 77, 81 ). Sculpture of ca. 70 broad, regular, radial primary cords ( Figs 76–77, 79–81 ), with wide pustule-like folds, with longer axis parallel to aperture edge; cords gradually increasing in width towards aperture, each fold width ca. 4% of apertural length; in ventral third 4–5 secondary cords gradually appearing ( Figs 77, 80, 81 ); folds slightly elevated, pustule-like, ca. 3 times longer than wide, separated from neighboring folds in line by space ca. 1/4 of its width; interspaces ca. 1/10 cord’s width, except for posterior region, with interspaces similar to cord’s width; ca. 60 pustules along median cords; pustules in posterior area slightly taller than other areas ( Fig. 77 ). Selenizone short, almost filiform, width ca. 1/3 of foramen; edges simple and low; smooth internally ( Figs 76, 79, 80 ). Aperture planar ( Figs 77, 81 ), outline elliptical, width ca. 68% of length; edges slightly denticulated by radial sculpture. Inner surface smooth, glossy ( Figs 78, 82 ); narrow furrow in front of foramen, diminishing in strength at short distance from anterior edge ( Figs 82, 83 ). Septum ca. 60% of shell height; ca. 3 times higher than wide; ventral edge slightly concave, ca. 25% of aperture width; gradually narrowing up to posterior edge of foramen ( Figs 76, 79, 82, 83 ).

Measurements (in mm). Holotype: 3.3 by 1.4; Paratype MZSP 94183: 3.3 by 1.4 ( Fig. 79 ).

Distribution. Continental slope off Ceará, Brazil.

Habitat. Sandy bottoms with debris, 250 m (dead specimens).

Material examined. Types.

Etymology. The specific epithet is derived from the collecting locality, the seamount Canopus, arbitrarily changing to feminine termination “ canopa ” (rather than –ensis) for phonetic reasons, being a noun in apposition. Canopus is also a large star of the Carina constellation, only visible in the Southern hemisphere, where the species occurs.

Figures

FIGURES 76 – 83: Cranopsis canopa n. sp. types. Fig: 76, holotype, MZSP 107718 (L 3.3 mm), dorsal-slightly right view. Fig. 77: same, right view. Fig. 78: same, ventral view. Fig. 79: paratype MZSP 94183 (L 3.3 mm), dorsal view. Fig. 80: paratype MZSP 90281, SEM, dorsal-slightly left view (L 3.8 mm). Fig. 81: same, left view. Fig. 82: same, ventral view. Fig. 83: same, detail of central region, inner view (left side = 2.8 mm). FIGURES 84 – 87: Cranopsis columbaris n. sp., holotype MZSP 107719 (L 2.8 mm). Fig. 84: left view. Fig. 85: same, dorsal-slightly left view. Fig. 86: same, SEM right view. Fig. 87: same, dorsal-slightly right view.