Cylichna sp. 3

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 665-667

Cylichna sp. 3

Figs 36, 37E, F

MATERIAL EXAMINED. — New Caledonia proper. BATHUS 1: 160-222 m, 3 dd.

stn DE 697, Passe de Hienghène, 20°34’S, 164°58’E, 570-650 Loyalty Ridge. BIOGEOCAL: stn KG 227, 21°33’S, 166°24’E,

m, 1 dd; stn DE 700, Passe du Cap Baye, 20°57’S, 165°35’E, 500 m, 2 dd (Figs 37E, F).

FIG. 37. Shell morphology of undermined species of Cylichna Lovén, 1846 . A, Cylichna sp. 1 , (5 mm), ventral view, Wallis Island, MUSORSTOM 7 stn DW 604; B, same shell, posterior view. C, Cylichna sp. 2 , (2 mm), ventral view, New Caledonia, BIOGEOCAL stn CP 260; D, same shell, posterior view. E, Cylichna sp. 3 , (3.5 mm), ventral view, New Caledonia, BIOGEOCAL stn KG 227; F, same shell, posterior view. G, Cylichna sp. 4 , (1.5 mm), ventral view, New Caledonia, BATHUS 3 stn DW 800; H, same shell, posterior view.

DISTRIBUTION. — Collected from New Caledonia (Fig. 36), in 222-570 m.

DESCRIPTION. — Shell morphology. Length 3.5 mm, width 2 mm (largest specimen examined). Shell fragile, oval, with convex sides (Fig. 37E). Only 1 whorl visible, forming nearly the entire shell. Apex rounded, concave (Fig. 37F), with the aperture lip rising slightly from the left side, and forming a short wing connected to the columellar margin. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing abruptly at about 1/3 of its length. Columellar margin slightly thickened. Columella smooth, with no folds. Umbilicus closed. Sculpture of a number of irregular inconspicuous spiral grooves crossed by faint growth lines. There are 10 additional, well marked spiral grooves near the anterior end of the shell. Colour uniformly shiny white.

Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — The single specimen of Cylichna sp. 3 differs from other Indo-Pacific species of the genus. Considering the small size of the shells collected and the lack of anatomical information, it is possible that Cylichna sp. 3 is just a juvenile of another species of Cylichnidae . It is maintained provisionally as a distinct species until more specimens become available for study.

The generic placement of Cylichna sp. 3 is not clear. The shell resembles that of other species of Cylichna and therefore it is provisionally placed in this genus.