A molecular phylogeny of the 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. We use partial sequences from two ribosomal (16S, 28S) and two protein coding genes (COI, CAD) to examine the relationships among 55 genera, representing more than half of the genera in the region. Taxa were sampled to maximize representation of dung beetle morphological and ecological diversity in all nine tribes that occur in Africa. We estimated the divergence times of the tribes to determine relative ages. The phylogenetic hypothesis of tribal and generic relationships was found to largely concur with that of a recent molecular study done at a global scale, suggesting earliest diverging lineages which are quite distinct from the ones traditionally recognized. Thus recent calls for a new classification for Scarabaeinae are supported. We suggest possible changes to the classification, corroborate the likely African origin of the subfamily and provide support for fungus-feeding as the most likely ancestral feeding habit in the Scarabaeinae.