Genetic divergence and cryptic speciation in two morphs of the common subtidal nudibranch Doto coronata (Opisthobranchia: Dendronotacea: Dotoidae) from the northern Irish Sea

Abstract

The nudibranch genus Doto Oken [Dendronotacea, Dotoidae] contains numerous species which are important specialist predators of subtidal marine hydroids. The widespread species Doto coronata [Gmelin] is of particular taxonomic importance as the type species of the genus. Lemche [1976; J. mar. biol. Ass. U.K. 56: 691-706] identified several cryptic species within D. coronata, but the species is still suspected of being a species complex. Electrophoretic techniques were used to investigate genetic differentiation between 2 morphologically distinct samples of D. coronata found feeding on 2 different hydroid species off the south west of the Isle of Man [Irish Sea]. The results showed extensive genetic differentiation and indicate that the 2 morphs are separate species. These new species are described and it is suggested that other morphs of D. coronata on different hydroid species may represent further new species.