Tergipes tergipes (Forsskål, 1775)

Description

A very small aeolid nudibranch only 5–8 mm in body length. The body is translucent white, with a reddish-brown marking running along each side of the head into the bases of the cerata. The cerata sit in a single row along each side of the body and are narrow at the base, swelling toward the tip — a distinctive shape. The dark green digestive gland shows through each ceras, and the apex bears a white cnidosac.

Distribution

Originally described from the Øresund strait in Denmark. Subsequently recorded broadly across the North Atlantic — from Iceland and Norway down to Portugal and the Mediterranean — and also on the western Atlantic coast, giving the species an amphi-Atlantic distribution.

Etymology

The specific epithet tergipes combines the Latin tergum ("back") and pes ("foot"), meaning "having feet on the back" — alluding to the row of cerata that resemble little feet on the dorsum.

Remarks

A specialist on hydroids of the genus Obelia, particularly O. geniculata. It sequesters the prey's nematocysts in the cnidosac at each ceratal tip for defence. The species is the type species of the family Tergipedidae.

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References

• Limax tergipes, Forsskål P. (1775). Descriptiones Animalium, Avium, Amphibiorum, Piscium, Insectorum, Vermium; quae in Itinere Orientali Observavit Petrus Forskål. (Ed. Niebuhr C.). Hafniae: Möller. 164 pp.