Otitoma crassivaricosa, Morassi & Nappo & Bonfitto, 2017

Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, European Journal of Taxonomy 304, pp. 1-30 : 22-24

Otitoma crassivaricosa sp. nov.

urn:lsid:zoobank.org:act:54B1C89F-BA68-4388-B719-73B4B71BB55F

Fig. 6 A–H

Etymology

The specific epithet is a combination of the Latin words ‘ crassus ’ (thick) and ‘ varicosus ’ (bearing varices), alluding to the well developed axial sculpture.

Type material

Holotype

MARQUESAS ARCHIPELAGO: MUSORSTOM 9 , Stn DW 1218, Hiva Oa Island , 9°44.5 ′ S, 138°50.9 ′ W, 125–135 m ( MNHN IM-2000-32607 ).

Paratypes

MARQUESAS ARCHIPELAGO: Paratype 1, same data as holotype ( MZB 60216).

FIJI ISLANDS: Paratype 2, MUSORSTOM 10, Stn DW1365, 18°12.7 ′ S, 178°32.4 ′ E, 295–302 m ( MNHN IM- 2000-32608).

Description

Shell fusiform-cylindrical (b/l 0.37–0.40; a/l 0.50–0.52). Teleoconch of up to 5¾ weakly convex whorls. Suture distinct, bordered by a moderately prominent sutural fold, followed by a moderately concave sutural ramp. Axial sculpture consisting of opisthocline axial ribs, rather straight and rounded, equal to or wider than intervals, developing mainly in peripheral region, gradually disappearing on abapical portion of sutural ramp. 13–14 axial ribs on penultimate whorl, 11–12 on last whorl. Spiral sculpture consisting of widely-spaced cords, not forming distinct nodules at their intersection with axial ribs. First two teleoconch whorls with 3 spiral cords between sutural ramp and whorl base, increasing to 5–6 on later two whorls. Last whorl with 12 spiral cords on base and rostrum. Interspaces between spiral cords covered by microscopic spiral threads, 4–7 between spiral cords on later two teleoconch whorls ( Fig. 6 C–D). Aperture narrowly elliptical, constricted at entrance to siphonal canal. Siphonal canal short, slightly expanded at its end, and somewhat obliquely truncate. Outer lip edge sharp, preceded by a wide, prominent rounded varix. Stromboid notch strong. Anal sinus rather deep, apically rounded, its entrance strongly constricted by parietal pad. Protoconch narrowly conical, of 3¼ whorls, smooth except for presence of sparse microgranules, diameter 0.82–0.84 mm ( Fig. 6 E–H). Color yellowish-white with yellowish-orange spiral cords.

Dimensions

Holotype: 9.85 × 3.7 mm, aperture height 5.1 mm. Paratype 1: 9.3 × 3.7 mm, aperture height 4.65 mm; paratype 2: 11.2 × 4.1 mm, aperture height 5.3 mm.

Remarks

This species differs from its congeners by the combination of a narrowly conical protoconch, strong axial sculpture and well-developed secondary spiral sculpture. It may superficially resemble some specimens of O. cyclophora , from which it differs mainly in having broader axial ribs, a less constricted entrance to the anal sinus, and different protoconch features (narrowly conical, of 3¼ whorls rather than bluntly papillose, of about 1¾ whorls; see Kilburn 2004: 268).

Figures

Fig. 6. [next page] A–H. Otitoma crassivaricosa sp. nov. A–B. Holotype (MNHN IM-2000-32607), MUSORSTOM 9, Stn DW1218, Hiva Oa Island, Marquisas Archipelago, 9°44.5′ S, 138°50.9′ W, 125– 135 m, 9.85 × 3.7 mm. C. Teleoconch (not coated). D. Secondary spiral sculpture of the teleoconch (not coated). E–H. Protoconch (not coated). F. Microsculpture and of the protoconch (not coated). H. Color micrograph of the same protoconch. — I–N. Otitoma philpoppei sp. nov. I–J. Holotype (MNHN IM-2000-32609), Philippines, Mactan Island, 200 m, from local fishermen, 6.7 × 2.7 mm. K–N. Paratype (MNHN IM-2000-32610), BORDAU 1, Stn DW1464, Fiji, 18°09′ S, 178°38′ W, 285– 300 m. L. Teleoconch. M–N. Protoconch. — O–T. Otitoma nereidum sp. nov. O–P. Holotype (MNHN IM-2000-32611), BORDAU 1, Stn DW1464, Fiji, 18°09′ S, 178°38′ W, 285–300 m, 9.15 × 3.35 mm. Q–T. Paratype 2 (MZB 60216), BORDAU 1, Stn DW1494, Fiji, 18°55′ S, 178°29′ W, 240–319 m. R. Teleoconch. S–T. Protoconch, scale bar = 100 μm. Scale bars: C, E, R = 500 µm; D, L–N = 100 µm; F = 10 µm; K, Q = 1 mm.