Phylogenetic analysis of Geotrupidae (Coleoptera, Scarabaeoidea) based on larvae

Thirty-eight characters derived from the larvae of Geotrupidae (Scarabaeoidea, Coleoptera) were analysed using parsimony and Bayesian infer- ence. Trees were rooted with two Trogidae species and one species of Pleocomidae as outgroups. The monophyly of Geotrupidae (including Bolboceratinae) is supported by four autapomorphies: abdominal segments 3–7 with two dorsal annulets, chaetoparia and acanthoparia of the epipharynx not prominent, glossa and hypopharynx fused and without sclerome, trochanter and femur without fossorial setae. Bolboceratinae showed notable differences with Pleocomidae, being more related to Geotrupinae than to other groups. Odonteus species (Bolboceratinae s.str.) appear to constitute the closest sister group to Geotrupi- nae. Polyphyly of Bolboceratinae is implied by the following apomorphic char- acters observed in the ‘Odonteus lineage’: anterior and posterior epitormae of epipharynx developed, tormae of epipharynx fused, oncyli of hypopharynx devel- oped, tarsal claws reduced or absent, plectrum and pars stridens of legs well developed and apex of antennal segment 2 with a unique sensorium. A ‘Bolbelas- mus lineage’ is supported by the autapomorphic presence of various sensoria on the apex of the antennal segment, and the subtriangular labrum (except Eucanthus). This group constituted by Bolbelasmus, Bolbocerosoma and Eucanthus is the first evidence for a close relationship among genera, but more characters should be analysed to test the support for the clade. A preliminary classification at tribe level of Geotrupinae is suggested as follows: Chromogeotrupini (type genus Chromogeotrupes), Lethrini (type genus Lethrus), Taurocerastini (type genus Taurocerastes) and Geotrupini (type genus Geotrupes). Some ecological facts of Geotrupidae evolution could also be explained by the present results, such as those related to diet and nesting behaviour. Both coprophagy and male–female co-operation in nesting appear as derived traits.