Emarginula suspira, 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 : 453-455

Emarginula suspira new species

Figures 90–102

Emarginula tuberculosa: Leal, 1991: 41 (pl. 2, fig. F); Rios, 2009: 27 (fig. 49) (part) (non Libassi, 1859). Emarginula sp 1: Leal, 1991: 42 (fig. 2G).

Types. Holotype MNHN 25310. Paratypes: MNHN 25311, 16 shells, MZSP 102932, 5 shells, MZSP 102939, 2 shells, MNRJ 25959, 3 shells, all from type locality. Brazil. Espírito Santo (MD55; Bouchet, Leal & Métivier col); off Itaúnas, continental slope of Abrolhos, 18°59’S 37°48’W, 607–620 m, MNHN 25312, 5 shells (sta. DC73; 27/ v/1987); off Regência, 19°40’S 37°48’W, 790–940 m, MNHN 25313, 2 shells, MZSP 102921, 1 shell (sta. CB77; 27/v/1987); off Conceição da Barra, 18°58’S 37°49’W, 637 m, MNHN 25314, 1 shell (sta. CB76; 27/v/1987); Jaseur Seamount, 20°27’S 35°54’W, 54 m, MNHN 25315, 1 shell (sta. DC34; 15/v/1987); Montague Seamount, 20°26’S 36°41’W, 310–350 m, MNHN 25316, 1 shell (sta. CB79; 14/v/1987).

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 greatly curved inwards, located posteriorly, close to posterior apertural lip. Height ca. 40% of length. Sculpted by ca. 40 radial cords, regularly interrupted by concentric, less developed cords, forming nodes at intersections; mostly alternating wide and narrow cords. Slit ca. 30% of shell length.

Description. Shell size up to 7 mm; low, limpet-like; height ca. 40% of length. Pure white (Figs 93–95), ca.

10% of specimens with some pale beige pigmentation. Protoconch of 1.5 rounded whorls (Figs 91, 92); situated on right (Figs 94, 97); smooth, glossy; size 230 µm. Slit anterior, rectangular, width ca. 20% of length; opened anteriorly; ca. 8% of shell width and ca. 30% of shell length; edges rather irregular (Figs 93, 95, 96, 98, 99). Profile highly curved ventrally, sagittal profile as arc (imaginary center of ark located below middle point of dorsal surface, ca. 20% away from aperture) (Figs 94, 97); beak located close to posterior margin of aperture. Sculpture of ca. 40 narrow radial cords (Figs 90, 93, 97, 99–101); gradually more distinct towards aperture, wide and narrow cords disposed intercalating, narrow cords ca. 1/2–1/4 of wider cords (Figs 90, 93, 96, 99); concentric cords regularly distributed from apex to aperture ( Figs 100–101 ), ca. 1/2 to 1/3 width of primary radial cords; nodes at intersection of radial and concentric cords low in some specimens (Fig. 99), but frequently forming spine-like projections about as thick as cords (Figs 90, 93, 96); interspaces twice as wide as primary cords, covered by concentric sculpture; interval between concentric sculpture approximately twice as wide as threads; median threads with ca. 40 concentric cords; well preserved specimens with periostracum forming additional transverse, wide pits in concavity formed by radial and concentric cords (Fig. 99). Selenizone well-marked, edges sharp, as tall as adjacent radial cords; lunules regularly distributed (Figs 90, 93, 96, 99. 100). Aperture planar (Fig. 94) to slightly concave (Fig. 97), outline elliptical, width ca. 70% of length; edges undulating due to radial cords; posterior lip flattened, planar, ca. 20% of shell length; mostly convex (Fig. 95), rarely concave (Fig. 98). Inner surface smooth, glossy; apex cavity moderately deep, ca. 20% of shell length (Figs 95, 98, 102).

Measurements (in mm). Holotype: 6.8 by 2.9; paratypes MNHN 25311 (Fig. 96): 3.9 by 1.6; MNHN 25315 (sta. 34, Fig. 99): 2.7 by 1.4; MZSP 102932: #1, 5.0 by 2.7 (Fig. 90), #2, 4.0 by 1.7 ( Figs 100–102 ).

Distribution. Continental slope off Espírito Santo, Brazil.

Habitat. Sandy-mud bottoms, 54–940 m (dead shells).

Material examined. Types.

Etymology. The specific epithet is derived from the Portuguese word suspiro, a special dessert, a candy done with egg albumin and sugar; an allusion to general appearance of the shell somewhat resembling this delicate candy. The noun is in apposition.

Figures

FIGURES 100 – 102: Emarginula suspira n. sp. paratype MZSP 102932 in SEM (L 4.0 mm). Fig. 100: right view. Fig. 101: dorsal-slightly right view. Fig. 102: ventral view. FIGURES 103 – 108: Manganesepta atiaia, n. sp. Fig. 103: paratype MZSP 102946 (L 5.4 mm), dorsal view. Fig. 104: holotype MNHN 25317 (L 3.5 mm), right view. Fig. 105: same, dorsal view. Fig. 106: same, ventral view. Fig. 107: same, ventral-slightly left view. Fig. 108: same, right view, detail of apex (left side = 0.6 mm). FIGURES 109 – 115: Profundisepta denudata, n. sp., holotype MZSP 105507 (L 3.0 mm). Fig. 109: dorsal view. Fig. 110: left view. Fig. 111: detail of apex and foramen, dorsal view (upper side = 0.8 mm). Fig. 112: ventral view. Fig. 113: ventralslightly left view. Fig. 114: right view. Fig. 115: detail of apex, right view (L 1.2 mm).