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.