Caelatura tigrina, Absalão, Ricardo Silva, 2002

Absalão, Ricardo Silva, 2002, Three new species of Barleeidae (Mollusca, Gastropoda, Rissooidea) from Brazil, Zootaxa 56, pp. 1-7 : 2-5

Caelatura tigrina n.sp.

Caelatura sp. 1: Leal 1993 (p. 317: pl. 11, fig. C­H).

Diagnosis: Shell conic, whorls straight, non­umbilicate. Protoconch paucispiral with obsolete spiral sculpture. Teleoconch with 5 narrow well­spaced spiral cordlets, interspaces usually twice cordlet width. Color golden­brown with white axial flames in fresh material.

Description: Shell small, conic, whorls straight, golden­brown with white axial flames in fresh material. Length ranging from 2.34 to 2.38 mm; width from 1.32 to 1.35 mm. Protoconch paucispiral with obsolete spiral threads. Suture impressed. Apical angle around 40°. Teleoconch with about 5 spiral cordlets, 7 of them extending into base. Interspaces twice width of spiral cordlets, microsculptured by very fine, closely packed spiral threads. Top of spiral riblets with linear series of minute pits. Base straight, aperture oval, holostomate, anterior part of outer lip flaring outwards. No umbilicus. Operculum oval, solid, inner side bordered by one ridge, strong longitudinal rib present. A long peg rises from nucleus and extends beyond inner edge, but with a laminar expansion linking it to main body of operculum. Radula and anatomy not studied.

Type locality: Davis Seamount ­ MD 55 # DC 41 (20°39’ S / 034°43’ W), 58­ 70 m.

Type material: Holotype: MNRJ 8619; paratypes (five shells in each lot, except MNHN): IBUFRJ 12037; MNRJ 8620; MZUSP 35080; MORG 41053; ANSP 410285; MNHN (50 shells). All from type locality.

Additional material: MNHN; Dogaressa Seamount: MD 55 # DC 43 (20°51’ S / 033°45’ W), 63 m; MD 55 # DC42 20°54’7”S ­ 0 34 01’4”W, 60 m; Vitória Seamount: MD 55 # DC24 20 41’8”S ­ 0 37 49’5”W, 48­52 m; Davis Bank: MD 55 # DC40 20 39’8”S ­ 0 34 41’1”W, 60 m; MD 55 # DC41 20 38’5”S ­ 0 34 42’9”W, 58­ 70 m.

Etymology: From “ tigrina ” (Latin), of tigers, referring to the tiger­striped colour pattern of the shell.

Range: Vitória­Trindade Seamounts Chain, off Southeastern Brazil.

Remarks: The conical outline, shell colour pattern, and narrow spiral sculpturing of C. tigrina n.sp. are unique among South Americam Caelatura , and allow it to be easily distinguished from the other species with their convex outlines and thick spiral sculpturing. The operculum of C. tigrina n.sp. can be easily separated from that of C. barcellosi ( Absalão & Rios, 1995, p. 93, fig. 7) by its longer peg, the lack of a central axial rib, and the more conspicuous laminar expansion. C. pernambucensis (Watson, 1885) has flexuos axial ribs and very fine spiral threads, and cannot be confused with any other congener known from the region. A chink­like umbilicus may be present in some specimens, as in C. barcellosi ( Absalão & Rios, 1995, p. 89).

Caelatura speculabunda n.sp.

Caelatura sp. 3: Leal 1993 (p. 317: pl. 11, fig. N).

Diagnosis: Shell oval­pupoid. Whorls slightly convex, convexity concentrated in posterior part of whorls. Non­umbilicate. Protoconch paucispiral with 2­3 spiral cordlets. Teleoconch with 9­10 close, thick, spiral cordlets.

Description: Shell small, length ranging from 2.35 to 2.37 mm; width from 1.12 to 1.14 mm. Shell white, ovate­pupoid with slightly rounded whorls. Convexity mainly in posterior part of whorls. Suture impressed. Protoconch paucispiral with 2­3 spiral cordlets. Apical angle around 34o. Nine to ten thick spiral cordlets on body whorl. Interspaces with many minute threads, width variable but never as wide as cordlets. Base slightly rounded, with about 8 spiral cords. Anterior part of outer lip flaring slightly outward. No umbilicus. Operculum and radula unknown.

Type locality: Dogaressa Seamount: MD 55 # DC 43 (20°51’ S / 033°45’ W), 63 m.

Type material: Holotype: MNRJ 8621; Paratype: MNHN.

Etymology: From “specula” (Latin) looking for, attentive, and “bundus,” an ongoing action, referring to the active search for small gastropods far from the coast.

Range: Dogaressa Seamount.

Remarks: Caelatura spirocordata ( Absalão & Rios, 1995) is the most similar species to C. speculabunda n.sp., but the former has a more evenly convex shell and a rounded base, while C. speculabunda n.sp. has, in general, slightly convex whorls, which are most convex on the posterior part of the whorls. It also has more numerous spiral sculptures than does C. spirocordata in both teleconch and base. C. pernambucensis (Watson, 1885) and C. barcellosi Absalão & Rios, 1995 have axial ribs, which are lacking in this new species.