Author: (Alder & Hancock,1864)

Order: Nudibranchia  Family: Discodorididae

Maximum Size: 70 mm

Sightings: Sunshine Coast

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Thordisa villosa (Alder & Hancock,1864)

One of the larger species of Thordisa and usually found almost buried on sandy substrates. It is only rarely sighted (perhaps due to usually being buried) with distribution recorded at scattered locales across the Indo-Pacific. The specimen shown here was recorded from the Mooloolah River, Sunshine Coast, Queensland, Australia.

Colour is yellow with an irregular broad marginal band (sometimes broken into patches) of dark brown to black, together with some dark brown patches and spots mid-dorsum. Entire notum covered in conical papillae with some extended into long tapering filaments. Lamellate rhinophores are conical, brown with white edging to the lamellae and with a white tip. The gill is grey to pale brown.

The ventral surface of the mantle is pale yellow with irregular brown patches/spots whilst the sole of the foot is a more vibrant solid yellow with a brown margin.

Feeds on sponges.

Originally described as Doris villosa.
Placed in Thordisa by Eliot, 1904, a genus raised by Bergh in 1877.

David A. Mullins – January 2025

References:
– 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: 113-147

– Eliot, C. N. E. (1904). On some nudibranchs from East Africa and Zanzibar part. III. Proceedings of the Zoological Society of London. 1903:2:354-385.

– Rudman, W. B., 1999 (January 13) Thordisa villosa (Alder & Hancock, 1864). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/thorvill

– Prasade, A., Bhave, V., Patel, B. & Apte, D. (2013) First record of Thordisa villosa (Opisthobranchia: Nudibranchia: Discodorididae) from the west coast of India. Marine Biodiversity Records, Vol 6, e32

– 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.

– Gosliner, T. M., Valde ́s, A ́. & Behrens, D. W. (2018). Nudibranch & Sea Slug Identification – Indo-Pacific, 2nd Edition. New World Publications, Jacksonville, Florida, USA.