Opisthobranchiate Mollusca from Ghana: Discodorididae.

Abstract

Abstract
Descriptions are given of eight species of Doridoidea belonging to the family Goniodorididae from Ghana, West Africa. There are six species of Okenia of which Okenia impexa Marcus 1957 is known from both sides of the Atlantic, while the other five species are only known from West Africa: Okenia africana n. sp. has many long lateral processes; Okenia ghanensis n. sp. has short lateral processes of variable form, while Okenia species A and species B have not been named as they are known only from single specimens. The sixth species, Okenia digitata, characterised by three circlets of gills, was originally placed in a new genus Teshia Edmunds 1966, but retention of this genus can no longer be justified. Okenia africana n. sp. exhibits a stage intermediate between typical Okenia and Okenia digitata with one circlet of gills and two short rows of small gills in the position where O. digitata has secondary circlets. Two species of Trapania are also described, Trapania africana n. sp. with yellow spots and maroon papillae, and Trapania luquei Ortea 1989 which is also known from the Cape Verde and the Canary Islands.