Taxonomical study on the mollusks collected in Marion-Dufresne (MD 55) and other expeditions to SE Brazil: the Fissurellidae (Mollusca, Vetigastropoda)
Author
Simone, Luiz Ricardo L.
Author
Cunha, Carlo M.
text
Zootaxa
2014
3835
4
437
468
journal article
10.11646/zootaxa.3835.4.2
01da15e5-14ca-4506-89fd-2055b906f4ff
1175-5326
249622
F492B5ED-0CA7-436B-94AF-EE4C99D630AF
Cranopsis nymphalis
new species
Figures 31–39
Types
.
Holotype
MNHN 25293.
Paratypes
: MNHN 25294, 19 shells, MZSP 107717, 1 shell (
Figs 37–39
), MZSP
102927
, 14 shells, MNRJ 25958, 5 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 25295, 2 shells (sta. DC73); off Regência,
19°40’S
37°48’W
,
790–940 m
, MNHN 25296, 1 shell (sta. CB77).
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 downwards, located close to apertural level. Height 47% of length; width ca. 80% of length. Sculpted by ca. 40 strong radial ribs, relatively narrow, profile rounded, bearing transverse low scales extending to narrow interspaces of ribs. Fissure flanked by low, thread-like edges; located close to anterior edge, not completely separated from edge.
Description.
Shell size up to
10 mm
, low, limpet-like; height 47% of length. Pure white. Protoconch of 1.5 rounded whorls (Fig. 35); situated to right at posterior edge of apex (Figs 35–36); smooth, glossy; size 250 µm. Foramen cuneiform (pointed anteriorly), width ca. 12% of length; located anteriorly, barely open (possibly juveniles); 7% of shell width, 42% of shell length; edges irregular (Figs 31, 32, 34). Profile with beak curved ventrally, located on posterior edge (in dorsal view) (Fig. 33); teleoconch of one whorl; profile highly curved ventrally, sagittal profile as ark (center in middle level of dorsal surface, ca. 10% ventrally off aperture; Figs 33). Sculpture of ca. 40 regular primary radial ribs (Figs 32, 33), with rounded profile; secondary ribs initially rather fine, gradually increasing to size of primary ribs at margin; transverse, semilunar, low nodes as thickenings at intersection with radial sculpture, disposed along ribs in regular spaces equivalent to ca. 1/2 of ribs’ width; nodes continuing between ribs forming series of squared pits; interspaces between successive radial ribs ca. 1/3 their width; ca. 60 scales along ribs close to median line. Selenizone well-marked, as wide as fissure; edges barely taller than radial ribs, continuation from those of fissure, with sharp edges (
Figs 37, 38
); lunules well-spaced (Figs 31–32). Aperture planar (Fig. 33) elliptical in outline, width ca. 80% of length; edges undulating by radial sculpture. Inner surface smooth, glossy (Fig. 34); bearing several minute, radially aligned pits (
Fig. 39
). Septum very small, ca. 5% of shell height; as long as wide, ventral edge slightly concave, ca. 8% of aperture width; transforming into simple projected posterior edge of fissure (Figs 31, 32, 34, 39).
Measurements (in mm).
Holotype
: 7.2 by 5.0;
Paratype
MZSP 107717: 3.1 by 1.5 (
Figs 37–39
).
Distribution.
Known only from
type
locality.
Habitat.
Sandy mud bottoms,
295–940 m
depth (dead specimens).
Material examined.
Types
.
Etymology.
The specific epithet is derived from Greek,
nympha
, meaning bride, maiden spirit supposed to inhabit the sea and other natural places; an allusion to special, pretty radial sculpture of the shell.