Revision of the systematics of Babakina Roller, 1973 (Mollusca: Opisthobranchia) with the description of a new species and a phylogenetic analysis

Abstract

The genus Babakina was first described by Roller in 1973, with B. festiva as the type species. Since then a further two species have been described. A review of the literature reveals that many of the original descriptions as well as a few published additional studies offer limited information. This lack of information has produced confusion in the identification of the specimens and the number of valid species. Also, the question as to whether Babakinidae represents a distinct taxon or should be considered as part of the Glaucidae remained unresolved. The results demonstrate that the three described species of Babakina Roller, 1973 are differentiated by external and internal anatomical differences. Additionally, Babakina indopacifica sp. nov., from several western and central tropical Pacific tropical localities, is here described. Difference in the arrangement of the receptaculum seminis, shape of the penis, and shape and size of the bursa copulatrix are consistent between distinct species from different geographical regions. Radular morphology does not exhibit significant differences between species, with the exception that B. festiva and B. indopacifica have an asymmetrical distribution of denticles on either side of the central cusp while B. anadoni and B. caprinsulensis have symmetrical denticles. Preliminary phylogenetic analysis indicates that Babakina represents a monophyletic taxon. The phylogeny suggests that Babakinidae should be maintained as a distinct taxon separated from Flabellinidae and Facelinidae by several autapomorphies. © 2007 The Linnean Society of London, Zoological Journal of the Linnean Society, 2007, 151, 671–689.