The monophyly of Pachysoma MacLeay is assessed via cladistic analysis, based on sixty-four adult characters from thirty-seven taxa comprising all currently and previously recognized genera in Scarabaeini, except Madateuchus Paulian. Pachysoma comprises a monophyletic clade of derived species of Scarabaeus and Neopachysoma Ferreira is the sister lineage of Pachysoma sensu stricto. Scarabaeus (Pachysoma) stat. nov. is considered a subgenus of Scarabaeus Linnaeus while Neopachysoma Ferreira is maintained as a synonym of Pachysoma sensu lato. Neomnematium Janssens together with Mnematium MacLeay is polyphyletic, while the latter is paraphyletic. Mnematium MacLeay and Neomnematium Janssens are maintained as synonyms of Scarabaeus, and their species included in subgenera Scarabaeus (Scarabaeus) and Scarabaeus (Scarabaeolus). Drepanopodus Janssens, Kheper Janssens and Sceliages Westwood, as derived clades of Scarabaeus, could also be recognized as subgenera to maintain a monophyletic Scarabaeus, but are maintained as genera pending further work. Aridification of the Namib Desert is postulated to have initiated the evolution of Scarabaeus (Pachysoma), which feed on dry dung or detritus and are derived from a ball-rolling and wet-dung-feeding Scarabaeus-like ancestor. The evolution of flightlessness and food relocation strategy, biogeography, and additional distributional and biological information are presented for the group.
Publication Year
2003
Publication Site
Annals of the Transvaal Museum
Journal Volume
40
Page Numbers
47–71
Family
Scarabaeidae
General topic
Taxonomy
Abstract Note