(Alder & Hancock, 1846)
Atlantic coast of Europe from the Orkneys to northern Spain.
Locality: Scapa Flow, Orkney, intertidal, Scotland, U.K., North Atlantic, 18 March 1976 , Sheltered rocky shore. Length: 7 mm. Photographer: Ian F. Smith.
The ovate onchidorid, usually appears almost round when it is resting. It seldom grows larger than 5 mm in length but specimens can reach 10 mm. The mantle bears many small rounded tubercles.
The body is translucent brownish with scattered light and dark brown patches, the lighter patches being often much larger and merging to cover most of the mantle. There can be a dark brown ring around the base of the tubercles, and the mantle surrounding the rhinophore pockets is usually quite differently pigmented than the adjacent mantle. There are larger tubercles around the rhinophore pockets
It has been reported to feed on the bryozoans Cellepora pumicosa and Porella concinna
- Ortea, J. A. (1979). Onchidoris sparsa (Alder & Hancock, 1846) in Asturias, northern Spain. The Veliger 22(1): 45-48.
- Picton, B. E. and C. C. Morrow (1994). A Field Guide to the Nudibranchs of the British Isles. London, Immel Publishing Ltd.
- Thompson, T. E. and G. H. Brown (1984). Biology of Opisthobranch Molluscs Vol 2. 229 pp. 41 Pls. Ray Society 156.
- Thompson, T. E. (1988). Molluscs: Benthic Opisthobranchs (Mollusca: Gastropoda). Leiden, The Linnean Society of London.
Rudman, W.B., 2009 (November 29) Onchidoris sparsa (Alder & Hancock, 1846). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/onchspar