Thuridilla vataae (Risbec, 1928)

Yonow, Nathalie, 2012, Opisthobranchs from the western Indian Ocean, with descriptions of two new species and ten new records (Mollusca, Gastropoda), ZooKeys 197, pp. 1-130 : 17-18

Thuridilla vataae (Risbec, 1928) Fig. 6Plate 20

Elysia vataae Risbec, 1928: 281, pl. 12 fig. 7 (New Caledonia).

Elysia vatae . - Gosliner 1987: 53, fig. 43 (South Africa) (misspelling).

Thuridilla vatae . - Jensen 1992: 273 (Western Australia + Guam); Gosliner 1995: 15, figs. 14, 15, 16a (La Réunion + W Pacific); Apte 2009: 169, fig. 1x (Laccadive Islands) (misspellings).

Material.

Maldives: approx. 10 mm alive (3 mm pres.), Coral Garden on filamentous green algae, Vadhoo Reef, South Malé Atoll, 5 m depth, 14 October 1994, leg. RC Anderson & SG Buttress; specimen disintegrated (no radula found), 7 mm alive, Bathala Island reef, Ari Atoll, 8 m depth, 28 July 1995, leg. SG Buttress & RC Anderson ("colour dark with pale streaks, rhinophores appeared white with red tips"). - La Réunion and Mayotte: numerous individuals 10-15 mm in length http://seaslugs.free.fr/nudibranche/a_intro.htm.

Description.

Ground colour grey with hint of purple, covered with yellow spots and pustules, and round black dots. Marginal bands of the parapodia creamy yellow. Head white, forming X-shape into rhinophores anteriorly and body posteriorly; remainder of head and anterior part of body grey-black. Red-orange band at tip of each rhinophore, a distinctive character of the species; in this specimen, the rhinophores were faintly spotted with creamy yellow.

Preserved specimen semi-translucent with no pigment remaining except black spots on body. Parapodia folded over body and frontal margin bilobed (Fig. 6A). Pericardium unusual in Thuridilla vataae in that lateral and posterior vessels are connected. In this specimen, they appear to form a partial ring around the pericardium (Fig. 6A). Ventrally, foot and frontal margin both cleft in preserved specimen (Fig. 6B).

Remarks.

Thuridilla vataae is a small species recorded sporadically from the Indo-West Pacific. Risbec (1928) almost certainly named this species after the bay south of Nouméa, Baie de l’Anse Vata, of which the north-western tip is the collection locality of his single specimen, Rocher à la Voile. The suffix for commemoratives in this case is -ae, hence the spelling vataae. The original spelling is correct and should be maintained.