Thordisa villosa (Alder & Hancock, 1864)

Description

A large dorid nudibranch reaching about 70 mm. The dorsum is translucent yellow with a band of dark brown patches around the mantle margin, while the underside and foot are bright orange-yellow with scattered small brown spots. The back is densely covered with tubercles of varying size; the larger tubercles bear long, tapering, fluid-filled papillae, giving the animal a shaggy texture.

Distribution

Widespread in the Indo-West Pacific, recorded from India, Singapore, New Caledonia, Australia and Japan. The species was originally described from the coast of India.

Etymology

The specific epithet villosa is Latin for "shaggy" or "covered with soft hairs," after the tubercle- and papilla-covered dorsum.

Remarks

A sponge feeder. It is highly variable in colour and markings, and specimens treated as this species may include more than one distinct species.

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References

• Doris villosa n.sp., Alder J. & Hancock A. (1864). Notice of a collection of nudibranchiate Mollusca made in India by Walter Elliot Esq., with descriptions of several new genera and species. Transactions of the Zoological Society of London. 5(3): 113-147.
• Thordisa villosa, Chan J.M. & Gosliner T.M. (2007). Preliminary phylogeny of Thordisa (Nudibranchia: Discodorididae), with descriptions of five new species. The Veliger. 48(4): 284-308.
• アレノウミウシ, 中野理枝. (2018). 日本のウミウシ. 文一総合出版.