Molecular assessment of the systematics of African Scarabaeinae (Coleoptera: Scarabaeidae)

Abstract

Dung beetles of the subfamily Scarabaeinae have a worldwide distribution with the Afrotropical region, the putative origin of the diversification of Scarabaeinae, having the richest diversity. Partial sequences from two ribosomal (16S, 28S) and two protein coding genes (COI, CAD) are used to construct a molecular phylogeny of 55 genera sampled to maximize representation of dung beetle morphological and ecological diversity in all nine tribes that occur in Africa. The ages of the tribes are estimated for comparison with those of other biogeographical regions. The phylogenetic hypothesis was found to largely concur with a recent molecular study done at a global scale. Thus the recent calls for a new classification for the subfamily are validated. Possible changes to the classification are discussed and the likely African origin of the subfamily is corroborated. In addition, recent phylogenetic analyses having pointed to the canthonine dung beetle genus Epirinus as the putative African ancestral roller group. Consequently, the roller status of species in the genus is tested with observational studies and a molecular phylogeny based on the above genes is constructed for 16 of 29 species. Tested species were confirmed to be dung rollers. Monophyly of the genus was confirmed, lending support to the synonymisation of the wingless genus Endroedyantus with Epirinus. Moreover, the phylogenetic hypothesis was found to have a similar topology with a previously published one based on morphological data. A combined molecular/morphology analysis showed congruence between the molecular and morphological datasets. The loss of flight in some species and estimated divergence dates within Epirinus are discussed.