Sabatia supracancellata (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 : 690-692

Sabatia supracancellata (Schepman, 1913)

Figs 47, 49E, 52A, B

Atys (Alicula) supracancellata Schepman, 1913: 470 , pl. 32, fig. 4.

Synonym:

Sabatia ovata Habe, 1952 a: 75, text figs 11-12.

TYPE MATERIAL . — A. supracancellata : probably lost (could not be located at ZMA). — S. ovata : not examined.

TYPE LOCALITY. — A. supracancellata : Sulu Sea, southern Philippines, 6°4.1’N, 120°44’E, 535 m [ Siboga : stn 102]. — S. ovata: Tosa Bay, southern Shikoku, Japan.

MATERIAL EXAMINED.— Philippines. MUSORSTOM 3: stn CP 417-425 m, 2 dd; stn DW 44 , Tanimbar Islands , 07°52’S, 132°48’E, 100, 14°00’N, 120°18’E, 189-199 m, 1 dd; stn CP 101 , 14°00’N, 291-295 m, 14 dd; stn CP 69 , 08°42’S, 131°53’E, 356-368 m, 1 lv 120°19’E, 194-196 m, 4 dd; stn DR 102 , 14°01’N, 120°18’E, 192 (Fig. 49 E); stn CP 70 , 08°41’S, 131°47’E, 413- 410 m, 1 dd (Figs m, 1 dd; stn CP 139 , 11°53’N, 122°14’E, 240-267 m, 3 dd; stn 52 A, B); stn CP 71 , 08°38’S, 131°44’E, 477-480 m, 2 dd; stn CP CP 143 , 11°29’N, 124°11’E, 205-214 m, 2 dd. 75, 08°46’S, 131°36’E, 451-452 m, 1 dd .

Indonesia. KARUBAR:stn DW 13, Kai Islands, 05°26’S, 132°38’E,

DISTRIBUTION. — Originally described from the Sulu Sea , southern Philippines, in 535 m (Schepman, 1913). Subsequently reported from Zanzibar, Tanzania, East Africa (Thiele 1925). Material herein from the Philippines and Indonesia (Fig. 47), in 192-477 m, live in 356-368 m.

DESCRIPTION. — Shell morphology. Length 8 mm, width 5 mm (largest specimen examined). Shell solid, oval, with convex sides and only 1 whorl visible (Fig. 52 A). Apex depressed, not umbilicate (Fig. 52 B), with the aperture lip conspicuously rising from the left side, forming a short wing. Anterior end of the shell rounded. Aperture as long as the shell, wider anteriorly and narrower posteriorly. Columellar margin conspicuously thickened, with a large callus composed of numerous tubercles and situated on the posterior half of the aperture. Sculpture of several punctuated spiral grooves, absent from the middle area of the shell, and more densely concentrated towards the posterior end. Near the apex, the punctuations are larger and more densely arranged, and the areas between the spiral grooves are thicker. Colour uniform cream to light brown.

Anatomy. The digestive system lacks gizzard plates. The radular formula is 15 x 1.0. 1 in a specimen from Indonesia (KARUBAR stn CP 69). The lateral teeth are hook-shaped and smooth, with no denticles (Fig. 49 E). They have a large base and a short, curved cusp.

REMARKS. — Sabatia supracancellata was described by Schepman (1913) in Atys Montfort, 1810 for a single shell collected in 535 m in the Philippines. The type material is apparently lost; it could not be located at ZMA. The material here examined, collected from the Philippines and Indonesia, matches the original description and clearly belongs to this species.

This species is clearly distinguishable from other members of the genus in several regards. The shell of S. supracancellata is much smaller than that of Sabatia nivea and Sabatia pustulosa and has a conspicuous wing on the apex of the shell. More importantly, S. supracancellata lacks gizzard plates, which are present in most other members of the Cylichnidae (except S. pyriformis ). However, other shell characteristics, such as the sculpture and the presence of a callus on the anterior end of the columella are very similar to those of other members of Sabatia . Additionally, the radula of S. supracancellata has a single lateral tooth with a large base and a short, curved cusp, very similar to those of

FIG. 52. Shell morphology of species of Sabatia Bellardi, 1876 . A, Sabatia supracancellata (Schepman, 1913) , (8 mm), ventral view, Indonesia, KARUBAR stn CP 70; B, same shell, posterior view. C, Sabatia sp. , (13 mm), ventral view, Philippines, MUSORSTOM 3 stn DR 93. D, Sabatia pyriformis n. sp., holotype MNHN 20383 (7 mm), ventral view, New Caledonia, BATHUS 1 stn CP 698; E, same shell, posterior view.

S. nivea and S. pustulosa . In the absence of a phylogenetic hypothesis, it is not possible to determine the generic position of this species and it is here placed in Sabatia pending future study. The absence of gizzard plates could constitute an autapomorphy of this species and Sabatia pyriformis , described above.

Habe (1952a) described Sabatia ovata from Japan with the same shell morphology as Sabatia supracancellata and they are here regarded as synonyms.

The shell of this species recorded by Thiele (1925) from East Africa is similar to the shells here examined, but because of the geographic distance between the known range of this species in the southwest Pacific and East Africa this record needs anatomical confirmation.