Thordisa villosa, (Alder & Hancock, 1864)

Valdés, Ángel, 2002, A phylogenetic analysis and systematic revision of the cryptobranch dorids (Mollusca, Nudibranchia, Anthobranchia), Zoological Journal of the Linnean Society 136 (4), pp. 535-636 : 574

THORDISA VILLOSA ( ALDER & HANCOCK, 1864)

Doris villosa Alder & Hancock, 1864: 119–120 , pl. 33, fig. 1.

Thordisa maculigera Bergh, 1877a: 540–542 , pl. 61, figs 19–24, pl. 62, figs 1, 2.

Thordisa stellata Eliot, 1904: 368 .

Type material

Doris villosa Alder & Hancock , SYNTYPES: Madras, India, two specimens, 7–13 mm preserved length, dried, leg. W. Elliot ( HMNC 20, 42). Thordisa maculigera Bergh , HOLOTYPE (by monotypy): Cebu, Philippines 1864, 15 mm preserved length, leg. C. Semper ( ZMUC GAS- 2102). The type material of Thordisa stellata Eliot is untraceable; it could not be located in BMNH.

Remarks

Alder & Hancock (1864) described Doris villosa from India, based on two specimens having the dorsum covered with processes with filaments. The living animals were ochre yellow to orange with large brown botches surrounding the mantle margin. Bergh (1877a) described Thordisa maculigera from the Philippines, but provided no information of the colour in the living animal. Years later, Bergh (1902) reported this species from the Gulf of Thailand and recognized that it is probably a synonym of Doris villosa .

Eliot (1904) redescribed Doris villosa based on one specimen from East Africa, which clearly fits with the original description by Alder & Hancock (1864). At the same time, he synonymized it with Thordisa maculigera , with some reservations due to differences in the radular morphology. Later, Eliot (1906c) reaffirmed his opinion on the synonymy of D. villosa and T. maculigera , based on the examination of more specimens. He also examined the type material of Doris villosa , but the two syntypes had the buccal mass removed, and comparison of the radular morphology was not possible. Eliot (1906c) also regarded Thordisa stellata Eliot, 1904 as a synonym of D. villosa .

Unfortunately I was unable to find complete specimens for this study. The syntypes of Doris villosa are poorly preserved, but I found the radula, mounted on a slide, in the HMNC collections. This radula is very similar to the drawings of the radula of Thordisa maculigera by Bergh (1877a) and there is no doubt these two names are synonyms.