Thecacera Fleming, 1828

Vallès, Yvonne, Valdés, Ángel & Ortea, Jesús, 2000, On the phanerobranch dorids of Angola (Mollusca, Nudibranchia): a crossroads of temperate and tropical species, Zoosystema 22 (1), pp. 15-31 : 26

Genus Thecacera Fleming, 1828

TYPE SPECIES. — Doris pennigera Montagu, 1815

Thecacera pennigera (Montagu, 1815) ( Figs 7C ; 9 )

Doris pennigera Montagu, 1815: 17 , pl. 4, fig. 5.

Thecacera maculata Eliot, 1905: 241-243 .

Thecacera lamellata Barnard, 1933: 294-295 , fig. 1.

MATERIAL EXAMINED. — Namibe Province. Praia Amelia, 15°01’S, 12°08’E, 3.VIII.1985, 1 specimen 6 mm preserved length.

DISTRIBUTION. — Thecacera pennigera has been collected from Britain, the Netherlands, France, Sicily, South Africa, Pakistan, Japan, Australia, New Zealand and Brazil (see Willan 1976). Our data represents the first report of this species in Angola.

DESCRIPTION

The background colour is white in the living animal. The whole body is covered by orange, yellow and black spots ( Fig. 9 ). The velum has two lateral prolongations. The rhinophores, the rhinophoral sheath, the gill (with five bipinnate branchial leaves) and the two extrabranchial processes (very long) are covered with orange, yellow and black spots as well.

The radular formula is 8 × (2.2.0.2.2). The innermost lateral tooth is smaller than the second. Both of them have a peaked hook shape ( Fig. 7C ). The base of the inner lateral is larger than the peak. The two outer lateral teeth are smaller than the inner laterals. The outermost lateral is smaller than the innermost. Both outer laterals are rectangular in shape.

REMARKS

As in our specimen, Thompson & Brown (1984) described specimens of Thecacera pennigera (Montagu, 1815) as being white with numerous irregular-shaped orange areas and black and yellow spots. However, the rhinophores described by Thompson and Brown had a yellow upper part with black speckling, while the whole rhinophore of our specimen is white with black, yellow and orange speckling. The branchial leaves are also similar, but our specimen has not only black and orange, but also yellow spots.

Figures

FIG. 7. — Radular teeth morphology; A, Polycera hedgpethi (MNHN); B, Polycera aurantiomarginata (MNHN); C, Thecacera pennigera (MNHN). Scale bar: 100 µm.

FIG. 9. — Thecacera pennigera (MNHN); A, dorsal view of the living animal; B, lateral view of the living animal. Scale bar: 1 mm.