Phylogenetics of South American Biomphalaria and description of a new species (Gastropoda: Planorbidae).

Abstract

The planorbid snail Biomphalaria edisoni n. sp. is described from morphological and molecular characters, based on specimens collected at two localities in Colombia. The new species has the typical features of the genus, as well as the following characteristics: vaginal pouch, numerous prostatic diverticular arranged in racemes, penis sheath/prepuce ratio of approximately 2 and a penial complex half the length of the cephalic portion of the female duct. These elements differentiate it from B. kuhniana, which was also present in one of the localities, and also from B. prona,B. helophila and B. nicaraguana, with which it has greater morphological similarities. Phylogenetic analysis of the nucleotide sequences of the internal spacers of the ribosomal DNA transcript (ITS1, ITS2) of B. edisoni n. sp. and 14 neotro-pical Biomphalaria species indicates that the former belongs to the monophyletic group including B. prona and B. sp. from Cuba. The genetic distances within this monophyletic group are however great enough for B. edisoni n. sp. to be regarded as a separate species. Thus morphology, phylogenetic tree topology and genetic distances all support the recognition of B. edisoni as a new species.