Volvulella ovulina

Valdés, Ángel, 2008, Deep-sea “ cephalaspidean ” heterobranchs (Gastropoda) from the tropical southwest Pacific, Mémoires du Muséum national d'Histoire naturelle 196, pp. 587-792 : 748-751

Volvulella ovulina (A. Adams in Sowerby, 1850)

Figs 81A, 82

Bulla ovulina A. Adams in Sowerby, 1850 [in 1848-50]: 155.

FIG. 81. Shell morphology of species of Volvulella Newton, 1891 . A, Volvulella ovulina (A. Adams in Sowerby, 1850), (3.5 mm), ventral view, Indonesia, KARUBAR stn CP 75. B, Volvulella onoae n. sp., holotype MNHN 20430 (3 mm), ventral view, New Caledonia, MUSORSTOM 4 stn DW 150. C, Volvulella fortis (Thiele, 1925) , (2.5 mm), ventral view, New Caledonia, BATHUS 1 stn DW 654. D, Volvulella multistriata n. sp., holotype MNHN 20427 (4 mm), ventral view, VAUBAN stn 40. E, Volvulella sp. , (6 mm), ventral view, Philippines, ESTASE 2 stn CP 6.

Synonym:

Volvula minutissima Thiele, 1925: 350 , pl. 31, fig. 24.

TYPE MATERIAL. — B. ovulina : not examined . — V. minutissima : not examined.

TYPE LOCALITY. — B. ovulina: Mino-Sima [= Mishima], Japan, 115 m . — V. minutissima : Sumatra, Indonesia .

MATERIAL EXAMINED. — Indonesia. KARUBAR: stn CP 71, Tanimbar Islands , 08°38’S, 131°44’E, 477-480 m, 3 dd; stn CP 75, 08°46’S, 131°36’E, 451-452 m, 2 dd (Fig. 81A) .

DISTRIBUTION. — Known from Japan and the southern China Sea, in 10-410 m (Hori, 2000c). Record herein from Indonesia (Fig. 82), in 452-477 m.

DESCRIPTION. — Shell morphology. Length 3.5 mm, width 1.5 mm (largest specimen examined). Shell solid, oval, with nearly parallel sides (Fig. 81A). Only 1 whorl visible, forming the entire shell. Anterior end of the shell rounded. Umbilicus narrow. Aperture long, wide anteriorly, narrowing at about 1/4 of its length. At its apical end, the aperture bends over the apex of the shell and the parietal wall forms a large, conical spine that completely covers the apex. Columellar margin thickened, with a small protuberance. Sculpture of 5 faint and irregular spiral grooves at the anterior end of the shell, and numerous fine growth lines all over its surface. Colour uniformly shiny whitish.

Anatomy. Unknown. All shells collected lacked soft parts.

REMARKS. — The material here examined is very similar to the shell illustrated by Hori (2000c) and it is clear that the Indonesian specimens belong to Volvulella ovulina .

Volvulella minutissima , described by Thiele (1925) from Sumatra, Indonesia, is probably a juvenile of this species and is here regarded as a synonym, pending availability of additional material.