First phylogenetic analysis of the subfamily Pachydeminae (Coleoptera, Scarabaeoidea, Melolonthidae): the Palearctic Pachydeminae

Abstract

This paper presents the first phylogeneticanalysis of Pachydeminae Reitter, 1902; one of the least known subfamilies of Melolonthidae, ‘leafchafers’ (Scarabaeoidea, Coleoptera). Some species of Pachydeminae have recently become agricultural pests in southern Spain. We analysed the phylogenetic relationships among 49 species belonging to 16 genera in the Palearctic region, based on a set of 63 morphological characters from the adult external morphology, wing anatomy, mouthparts and male and female genitalia. The last three sets of characters are described here for the first time. The phylogeny shows that the Palearctic Pachydeminae are monophyletic within the subfamily. Mouthparts and male and female genitalia provide the best synapomorphies for intergeneric relationships. In contrast, most of the external morphological characters used in the taxonomy of Pachydeminae are highly homoplastic. The phylogeny shows a basal split between the genera Hemictenius Reitter, 1897; Pachydema Castelnau, 1832, and the monospecific Peritryssus Reitter, 1918; and a second clade including the rest of genera. The remarkable Peritryssus is confirmed as a Pachydeminae, being the sister group to the monophyletic Hemictenius. Except for the position of P. rubripennis (Lucas, 1848) and P. zhora Normand, 1951, the phylogeny supports the monophyly of Pachydema but rejects the traditional division into species groups and the monophyly of the endemic Canarian species. In contrast, Tanyproctus Faldermann, 1835, must be rejected as polyphyletic. Otoclinius Brenske, 1896, is also probably polyphyletic(two new species synonymies), whereas Leptochristina Baraud and Branco, 1991, is either mono- or paraphyletic. The two Mediterranean genera Ceramida Baraud, 1897, and Elaphocera Gene´ , 1836, form a monophyleticgroup, this clade being the best supported by the data set. Ceramida is clearly monophyletic, whereas Elaphocera is probably monophyleticexc ept for E. barbara Rambur, 1843, which shares with Ceramida the character state for numerous mouthpart and genitalic characters. The phylogeny questions the genericstatus of the small and monospecific genera of Pachydeminae. The monotypic Alaia Petrovitz, 1980, and Brenskiella Berg, 1898, are merged with Europtron Marseul, 1867, into one clade, whereas Atanyproctus Petrovitz, 1954, is grouped with some species of Tanyproctus, and the monotypic Pachydemocera Reitter, 1902, is proposed as a junior synonym of Elaphocera.