Natica pipoca, Simone, 2014

Simone, Luiz Ricardo L., 2014, Taxonomic study on the molluscs collected during the Marion-Dufresne expedition (MD 55) off SE Brazil: the Naticidae (Mollusca: Caenogastropoda), Zoosystema 36 (3), pp. 563-593 : 582-586

Natica pipoca n. sp.

( Fig. 9 F-I)

HOLOTYPE. — MNHN 27156 .

PARATYPES. — MNHN 27157, 19 shells, MZSP 105142, 6 shells from type locality.

TYPE LOCALITY. — Brazil. Espírito Santo: off Regência, MD 55 sta. DC87, 19°34’S, 39°42’W, 15 m, 29. V.1987 (coll. Bouchet, Leal & Métivier).

DIAGNOSIS. — Shell c. 2 mm, c. 85% taller than wide. Umbilicus entirely closed by callus. Sculpture lacking, surface glossy, translucent, basic color white, with irregular pale brown chevrons splayed and mostly coalescent. Protoconch dome-shaped, of 1.5 whorls. Operculum smooth, glossy, with low fold in outer edge. Spire angle c. 120°.

DESCRIPTION

Shell ( Fig. 9 F-H)

Diameter of c. 2 mm; height c. 85% of width; general form globose. Color translucent white in base; irregular pale brown chevrons splayed and mostly coalescent in most area except for peri-umbilical area ( Fig. 9G ). Protoconch domeshaped, of 1.5 flattened whorls ( Fig. 9H ); surface smooth, glossy; diameter c. 0.2 mm, occupying c. 10% of upper shell surface. Teleoconch of c. 2.5 whorls; suture planar, weakly marked; spire angle c. 120°. Sculpture absent except for growth lines. Aperture semicircular, wide, occupying c. 74% of shell height and c. 44% of shell width; outer lip thick, weakly prosocline, simple; inner lip slightly concave to almost straight ( Fig. 9F ), almost entirely covered by thick callus. Umbilicus entirely covered by thick callus, only short lower portion of umbilicus remaining uncovered ( Fig. 9F ); its aperture occupying c. 15% of lower surface.

Operculum ( Fig. 9F, I )

Semi-circular, thin, calcareous, occupying entire aperture. Nucleus in middle of inner-lower quadrant; spiral sculpture with 2 barely visible whorls; low undulations parallel to inner edge. Inner surface smooth, glossy; scar elliptical (twice wider than long), closer to inner edge, occupying c. 40% of inner surface.

Measurements (width and height in mm)

Holotype ( Fig. 9H, I ): 2.1 × 1.8.

Paratype: MZSP 105142: 2.1 × 1.8.

Habitat

15 m depth, muddy bottoms (included living specimens).

Etymology

The specific epithet is a nom in apposition, from the native Tupy word pipoca , meaning cracked skin, an allusion to the appearance of the shell spotted surface.

Natica juani Costa & Pastorino, 2012 ( Fig. 10A, B )

Natica juani Costa & Pastorino, 2012: 30-32 , figs 21-28, 30, 37-40.

Natica cf. sagrayana – Simone 2011: 167, 269, 276, 283, 290, 297, 304 (non d’Orbigny, 1850).

EXAMINED MATERIAL. — Brazil. Espírito Santo: off Itaúnas , MD55 sta. DC82, 18°56’S, 37°52’W, 85-105 m, 28.V.1987 (coll. Bouchet, Leal & Métivier), MNHN, 2 shells (coll. Bouchet, Leal & Métivier) ; Trindade Island , MD55 sta. DC59, 20°30’S, 29°18’W, 52-60 m depth, 22.V.1987 (coll. Bouchet, Leal & Métivier), MNHN, 1 shell (coll. Bouchet, Leal & Métivier) .

REMARKS. — Natica juani has been described including the material examined by Simone (2011), which provisionally determined the samples as N. cf. sagrayana. The known distribution was from Rio de Janeiro to Uruguay ( Costa & Pastorino 2012: 31). The three specimens presently studied are dry, but well-preserved young shells; this indicates low transportation. The two samples expand the known distribution of the species northward, reaching middle Espírito Santo coast, and to east, reaching Trindade oceanic island. The deepest known environment also increases from 65 m to 105 m.

Figures

FIG. 9. — Shells of MD55 naticid species: A-E, Natica jukyriuva n. sp., shell holotype: A, apertural view; B, right view; C, dorsal view; D, apical view;E, detail of apex;F-I, Natica pipoca n. sp.,shell, holotype:F, apertural view;G, dorsal view;H, apical view;I, operculum, outer view. Measurements: A-D, W 9.2 mm; E, side, 2.5 mm; F-H, W 2.1 mm; I, 1.4 × 0.9 mm.

FIG. 10. — Shells and operculum of MD55 naticid species; A, B, Natica juani Costa & Pastorino, 2012, shell MNNH (sta. DC82): A, dorsal view; B, apertural view; C, D, collected isolated operculum of a Natica ss; C, outer view; D, inner view; E-K, Eunaticina abyssalis n. sp. holotype: E, frontal view; F, dorsal view; G, apical view; H, umbilical view;I, detail of apex; J, protoconch, apical view; K, detail of superficial sculpture in middle level of body whorl. Measurements: A, B, W 3.0 mm; C, D, 14.4 × 8.3 mm; E-H, W 26.6 mm; I, K, 1.0 mm; J, 1.6 mm.