Analysis of 55 morphological characters yielded a phylogenetic reconstruction of the
Diopatra complex, currently including three genera (
Diopatra,
Epidiopatra, and
Paradiopatra). The results reject the monophyletic status of the complex and all three genera analysed. It is suggested that several parallel and independent events of paedomorphic evolution took place within the genera
Diopatra and
Paradiopatra, which led to the recognition of two artificial genera
Epidiopatra and
Notonuphis. The following taxonomic revisions are proposed: (1)
Epidiopatra as a junior synonym of
Diopatra; (2)
Notonuphis as a junior synonym of
Paradiopatra; (3) the
Diopatra complex, consisting of two sister genera
Diopatra and
Paradiopatra, and two basal genera
Paxtonia gen. nov. and
Protodiopatra gen. nov., erected for two species previously included in
Paradiopatra. Reconstruction of phylogenetic relationships within
Paradiopatra yields a few reliable clades comprising well-defined groups of species, but supported by homoplastic synapomorphies representing highly adaptive characters. Twenty-six valid species of
Paradiopatra, including a new species,
Paradiopatra pyricirra sp. nov., are described or re-described and illustrated based on original descriptions and re-examination of type and non-type material. Identification keys to genera included in the
Diopatra complex, and to all accepted
Paradiopatra species, are presented.
