Molecular phylogenetics and evolution of the food relocation behaviour of the dung beetle tribe Eucraniini (Coleoptera : Scarabaeidae : Scarabaeinae)

A phylogenetic analysis using 28S and 18S rDNA provides evidence that the tribe Eucraniini is a monophyletic group and the sister-group of the Phanaeini and Dichotomiini. Our molecular phylogeny of the dung beetle tribes provides strong evidence for the monophyly of the subfamily Scarabaeinae. The monophyly of the tribe Eucraniini is well supported and it includes the genera Anomiopsoides Blackwelder, Ennearabdus van Lansberge, Eucranium Brullé and Glyphoderus Westwood. The food-lifting relocation behaviour present in species of Eucranium, Anomiopsoides and Glyphoderus is considered a derived condition and it most probably evolved from tunnelling behaviour. The preference for dry dung or dung pellets by species of Eucraniini genera, and feeding on plant material by species of Anomiopsoides, are considered apomorphic. Our analyses suggest that rolling behaviour in the Scarabaeinae evolved at least twice during their evolution. The incidence of high endemicity of dung beetles in the Monte biogeographic province of Argentina suggests that the area constitutes an independent centre of evolution. Our hypothesis is that a vicariant event was responsible for the divergence of the Eucraniini from a Neotropical lineage ancestral to Eucraniini and Phanaeini. The isolation of the Eucraniini lineage probably occurred after the Andean uplift during the Quechua diastrophism (middle Miocene) that resulted in the creation of xeric plains in austral regions of South America.