Otitoma tropispira Morassi & Nappo & Bonfitto 2017, sp. nov.
Creators: name: Morassi, Mauro
name: Nappo, Andrea
name: Bonfitto, Antonio
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Neogastropoda
Turridae
Otitoma
Otitoma tropispira

description: Otitoma tropispira sp. nov.
urn:lsid:zoobank.org:act: 85D8CD51-3521-4BEB-B393-80F55132AAF6
Fig. 3 M–R
Etymology
The specific epithet comes from a combination of the Greek ‘ tropis ’ (a keel) and the Latin ‘ spira ’ (spire), alluding to the strong spiral sculpture of the keel-like cords.
Type material
Holotype
NEW CALEDONIA: BATHUS 2, Stn DW 747, S of New Caledonia, 22°30 ′ S, 166°260 ′ E, 574 m (MNHN IM-2000-32591).
Paratypes
NEW CALEDONIA: paratype 1, same data as holotype (MNHN IM- 2000-32592); paratypes 2 (MZB 60212) and 3 (MNHN IM- 2000-32593), SW of New Caledonia, Boulari Passage, 400 m; paratype 4, BATHUS 4, Stn CP946, N of New Caledonia, 20°34 ′ S, 164°58 ′ E, 386–430 m (MNHN IM- 2000- 32594); paratype 5, BATHUS 1, Stn DW683, off E coast, 20°35 ′ S, 165°07 ′ E, 380–400 m (MNHN IM- 2000-32595); paratype 6, BATHUS 2, Stn DW758, S of New Caledonia, 22°18 ′ S, 166°11 ′ E, 377– 386 m (MNHN IM- 2000-32596).
Description
Shell fusiform (b/l 0.34–0.36; a/l 0.42–0.50). Teleoconch of 6–7 convex whorls with periphery at middle on earlier whorls, posterior to mid-whorl on later ones. Suture moderately deep, bordered by a prominent sub-sutural fold bearing a spiral cord, demarcated by a distinctly concave sutural ramp. Sculpture consisting of widely-spaced, narrow, keel-like spiral cords. Four earliest teleoconch whorls with a sub-sutural cord and two cords on abapical half of whorl, increasing to 3 on fifth and 4 on later two whorls. Last whorl with 11–15 spiral cords on base and rostrum. Sutural ramp with a narrow weak cord on its abapical part, becoming stronger on later two whorls (in paratype 5 (MNHN IM-2000-32595) comparable in strength to main spiral cords). Interspaces between spiral cords sculptured by numerous, very fine and faint spiral threads varying in number (up to about 13) (Fig. 3P). Axial sculpture represented only by incremental lines, more evident on sutural ramp, where they are arcuate in conformity with curvature of anal sinus. Aperture rather narrow, lanceolate, strongly constricted at entrance to siphonal canal. Siphonal canal long for genus, not notched terminally. Inner lip with moderately thin callus, parietal region with a pad formed at intersection with outer lip. Outer lip edge sharp, preceded by a wide, strong, rounded varix. Stromboid notch distinct, deep. Anal sinus deep, U-shaped, with strongly constricted opening. Protoconch conical, of 2½–2¾ smooth whorls. Protoconch diameter 0.81–0.92 mm (Fig. 3 Q–R). Color white or cream, with yellowish-orange spiral cords.
Dimensions
Holotype: 16.3 × 5.7 mm, aperture height 8.1 mm. Paratype 2 (largest specimen): 18.8 × 6.4 mm, aperture height 8.5 mm; paratype 6 (smallest specimen): 14.3 × 5.0 mm, aperture height 6.8 mm.
Remarks
Otitoma tropispira sp. nov. is distinguished from its described congeners by its rather large size (attains about 19 mm in maximum length) and the sculpture of its keel-like spiral cords, somewhat reminiscent of members of the pseudomelatomid genus Turridrupa Hedley, 1922. However, members of that genus have a weak to absent parietal pad, which does not constrict entrance to the anal sinus, and the interior part of the aperture is sculptured by spiral plicae. Furthermore, the protoconch of O. tropispira sp. nov. is smooth, while that of Turridrupa bears axial riblets on the last 1½–2 whorls (Kilburn 1988; Powell 1966).
description: Published as part of Morassi, Mauro, Nappo, Andrea & Bonfitto, Antonio, 2017, New species of the genus Otitoma Jousseaume, 1898 (Pseudomelatomidae, Conoidea) from the Western Pacific Ocean, pp. 1-30 in European Journal of Taxonomy 304 on pages 12-13, DOI: 10.5852/ejt.2017.304, http://zenodo.org/record/3825824