Phylogeny of the fish leeches (Oligochaeta, Hirudinida, Piscicolidae) based on nuclear and mitochondrial genes and morphology

Abstract

The phylogeny of the Piscicolidae was analysed from combined 18S rDNA, cytochrome c oxidase subunit I (CO‐I), nicotinamide adenine dinucleotide dehydrogenase subunit I (ND‐I) and morphological data using parsimony. A worldwide distribution of Piscicolidae was represented for the first time. While the family Piscicolidae was supported as a monophyletic group, the traditional subfamilies based on morphology were not supported. The Platybdellinae was polyphyletic and formed four distinct clades, and Bathybdella sawyeri did not group with any other platybdellins. The Piscicolinae was also polyphyletic, also forming four distinct clades. The pontobdellin genus Stibarobdella was shown to be the basal taxon within the Piscicolidae; however, the Pontobdellinae was found to be paraphyletic if Oxytonostoma was included. The genera Aestabdella, Austrobdella, and Malmiana were found to be paraphyletic; the genera Calliobdella, Cystobranchus, and Platybdella were found to be polyphyletic. The species Myzobdella lugubris was not found to be monophyletic. It is proposed that Oxytonostoma be transferred out of the Pontobdellinae, that Aestabdella be synonymized with Pterobdella, that Calliobdella vivida be returned to Cystobranchus, that Gonimosobdella be synonymized with Cystobranchus, and that Piscicolaria be synonymized with Myzobdella. The synonymy of Malmiana and Heptacyclus is confirmed, with Heptacyclus having priority. Piscicola milneri is confirmed to be a separate species from Piscicola geometra.