Subdivision of the genus Pleuroxus (Anomopoda, Chydoridae) into subgenera worldwide

Examination of many species of Pleuroxus from the entire World has revealed a major dichotomy in morphology, one line related to aduncus : the other to laevis both from Europe. Pleuroxus trigonellus (the type species of the genus) and Peracantha truncata are in two other distinct lines. The new subgenus Tylopleuroxus is proposed for the species related to aduncus , and the subgenus Picripleuroxus for those related to laevis. Tylopleuroxus is primarily Southern Hemisphere in distribution, Picripleuroxus primarily Northern Hemisphere. Evidence thus far suggests that probably most, perhaps all, of the taxa are confined to single continents or land masses.