Cylichna sp. 1

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 664

Cylichna sp. 1

Figs 36, 37A, B

MATERIAL EXAMINED. — New Caledonia proper. VAUBAN: — MUSORSTOM 6: stn DW 399 , 20°42’S, 167°00’E, 282 m, 2 stn 3, 22°17’S, 167°12’E, 390 m, 1 dd . — BIOCAL: stn DW 77 , dd; stn DW 406 , 20°41’S, 167°07’E, 373 m, 1 dd .

22°15’S, 167°15’E, 440 m, 1 dd. — BATHUS 1 : stn DW 688 , Wallis Island. MUSORSTOM 7: stn DW 523 , 13°12’S, 176°16’W, Passe de Hienghu , 20°33’S, 165°00’E, 270-282 m, 1 dd; stn DW 455-515 m, 5 dd; stn DW 601 , 13°19’S, 176°17’W, 350 m, 1 dd; 706, Passe SE de Ngoe, 21°42’S, 166°34’E, 247-252 m, 1 dd. stn DW 604 , 13°21’S, 176°08’W, 415-420 m, 2 dd (Figs 37A, B); Norfolk Ridge. BERYX 11 : stn CP 21, 24°44’S, 168°07’E, 430- stn DW 608 , 13°22’S, 176°08’W, 440-458 m, 1 dd .

450 m, 1 dd. Tonga. BORDAU 2: stn DW 1535, 21°43’S, 175°18’W, 268 m, Loyalty Ridge. BIOGEOCAL: stn KG 219, 22°39’S, 166°34’E, 1 dd.

570 m, 1 dd; stn DW 253, 21°32’S, 166°29’E, 310-315 m, 1 dd.

DISTRIBUTION. — Collected from New Caledonia, Tonga and Wallis Island (Fig. 36), in 252-455 m.

DESCRIPTION. — Shell morphology. Length 5 mm, width 2 mm (largest specimen examined). Shell solid, elongate, with nearly parallel sides (Fig. 37A). Only 1 whorl visible, forming nearly the entire shell, except for a visible portion of the spire. Apex rounded, deeply umbilicate (Fig. 37B), with the aperture lip not rising above the body whorl. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrowing gradually at about 1/5 of its length. Columellar margin conspicuously thickened. Columella with a small fold. Umbilicus closed. Sculpture of a number of inconspicuous spiral grooves crossed by faint growth lines. On the posterior end of the spire there is a distinctive pattern of curved and well-marked growth lines. Colour uniformly dirty white to pale brown.

Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — Cylichna sp. 1 resembles Cylichna grovesi n. sp. in shell morphology. However, these two species are clearly distinguishable by the presence of a more rounded apex in Cylichna sp. 1 and the narrower anterior end of the shell of C. grovesi .

This species is provisionally assigned to the genus Cylichna because of the resemblance of its shell morphology to that of other members of the genus, pending complete specimens becoming available for study.