Relichna truncatula (Schepman, 1913)

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 762

Relichna truncatula (Schepman, 1913)

Figs 85D, E, 89

Dinia truncatula Schepman, 1913: 471 , pl. 32, fig. 5.

TYPE MATERIAL. — One syntype ZMA 3.13 .126 .

TYPE LOCALITY. — Sulu Archipelago , Philippines, 05°43.5’N, 119°40’E, 522 m [ Siboga : stn 095] .

MATERIAL EXAMINED. — Philippines. The type material. 168°42’E, 340 m, 1 dd .

New Caledonia proper. LAGON: stn 830, Secteur de Poindimié, Fiji. MUSORSTOM 10: stn DW 1334, Bligh Water, 16°51’S, 20°49’S, 165°19’E, 105-110 m, 42 dd. 178°14’E, 251-257 m, 1 dd (Figs 85 D, E).

Norfolk Ridge. SMIB 5: stn DW 90, Banc Aztèque, 22°19’S,

DISTRIBUTION. — Originally described from Indonesia (Schepman 1913). Material herein collected from Fiji, New Caledonia and the Philippines (Fig. 89), in 110-522 m.

DESCRIPTION. — Shell morphology. Length 6 mm, width 3 mm (largest specimen examined). Shell solid, oval, with nearly parallel sides, narrower posteriorly (Fig. 85D). Only 1 whorl visible, except for a small visible portion of the top of the spire. Apex rounded, deeply umbilicate (Fig. 85E), with the aperture lip rising from the right side. The aperture lip forms a rounded wing connected to the columellar margin. Anterior end of the shell rounded. Umbilicus narrow, partially covered by a columellar extension. Aperture long, wide anteriorly, narrowing at about 1/4 of its length. Columellar margin thickened with a conspicuous tooth. Sculpture of a number of inconspicuous spiral grooves covering the entire shell. Colour uniformly dirty white.

Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — Schepman (1913) described Dinia truncatula based on 2 shells collected from the Sulu archipelago, Philippines. Examination of the remaining syntype of this species revealed that is it conspecific with the shells from Fiji and New Caledonia here examined .

The shells of Dinia truncatula resemble those of members of Relichna , described above, and the only feature that would suggest its inclusion in Diniatys Iredale, 1936 (the valid name for Dinia H. & A.Adams, 1854, which is preoccupied by Dinia Walker, 1854 [ Lepidoptera ]), is the presence of a conspicuous tooth on the columella, which is also present in several genera of Retusidae . This species is provisionally referred to Relichna pending anatomical information becoming available.