Aldisa zetlandica

(Alder & Hancock, 1854)

This rare species may reach a length of 35 mm, white to grey-green in colour, with yellow gills and rhinophores. The dorsal surface of the ample mantle bears pointed conical tubercles. The margins of the rhinophore pits are each protected by four to five tubercles. There are six to eight bipinnate gills. The oral tentacles are short and rounded. The propodium is bilaminate but lacks a notch in the anterior lamina.

Nothing is known about the diet of this dorid but other members of the genus eat demosponges.

There are only two recent confirmed reports of this species from around the British Isles: one from shallow water off western Ireland, and one from oilfields 200 miles to the north-east of the Shetland Islands. There are more frequent records from the Norwegian coast and off southern Sweden, to 280 m (Distr. A. zetlandica). The deepest record, however, comes from 1900 m off the coast of Iceland; the most southerly is from the Azores.