Phylogeny of the Oniticellini and Onthophagini dung beetles (Scarabaeidae, Scarabaeinae) from morphological evidence.

T Keith Philips

doi:10.3897/zookeys.579.6183

Abstract

A phylogenetic study was conducted to hypothesize relationships of most of the genera of the Oniticellini and Onthophagini for the first time using morphological characters from a diverse array of external and internal sclerites. The monophyly and sister relationship of both tribes was found using Bayesian and parsimony analyses with heavily to moderately weighted data. An alternative hypothesis based on parsimony analyses of unweighted or slightly weighted data show a paraphyletic Oniticellini without the Onthophagini, although recognition of the subtribe Helictopleurina as a tribe would eliminate non-monophyly.Of the three Oniticellini subtribes, the Helictopleurina and Drepanocerina are monophyletic. There is no support for the monophyly of the Oniticellina or the Onthophagini subtribe Alloscelina, as currently defined. The genus Liatongus is paraphyletic, while strong support was found for monophyly of the Madagascan genus, Helictopleurus. The genus Onthophagus is never monophyletic in any analysis performed. Two new subtribes are also proposed: Liatongina subtr. n. including the genus Liatongus and Attavicina subtr. n. including the genera Attavicinus and Paroniticellus.Topological evidence shows that the ancestral oniticellines and onthophagines were all coprophagous with alternative food sources evolving relatively recently. Both myrmecophily and termitophily probably evolved only once in the onthophagines. The phylogenetic analysis supports an African origin for the two tribes, with a relatively early age for the split of the Madagascar helictopleurines from the remaining oniticellines via dispersal. Furthermore, the presence of the oniticellines in the New World is hypothesized to be due to two relatively old dispersal events via Beringia and two relatively recent trans-Atlantic invasions of the Caribbean.

Highlights

The Oniticellini and Onthophagini contain close to one half of the roughly 7,000 species of scarabaeine dung beetles known worldwide (Schoolmeesters et al 2010).Undoubtedly more species remain undocumented, perhaps as many as 1,000 or more, and certainly a large proportion of those, when described, will be placed in either the speciose onthophagine genus Onthophagus or another closely related group
The tribe is monophyletic in the Bayesian tree (Fig. 2) and the Piwe weighted trees with K values from 1–10 (Figs 1A, 3, 4B)
In the molecular study of Monaghan et al (2007), the oniticellines and onthophagines were always a single clade based on parsimony or Bayesian 9 partition models

Summary

Introduction

The Oniticellini and Onthophagini contain close to one half of the roughly 7,000 species of scarabaeine dung beetles known worldwide (Schoolmeesters et al 2010).Undoubtedly more species remain undocumented, perhaps as many as 1,000 or more, and certainly a large proportion of those, when described, will be placed in either the speciose onthophagine genus Onthophagus or another closely related group. Onthophagus alone contains 1765 species (Hanski and Cambefort 1991) while a recent estimate put the total at ~2500 species (Tarasov and Solodovnikov 2011) With their high species diversity, these two tribes are among the most important in regards to understanding the evolution of the Scarabaeinae dung beetles. Many Oniticellini and Onthophagini (generic classification in Table 1) are tunnelers where dung is buried at the ends of tunnels created beneath a dropping and used as adult and larval food Within these tribes the behaviors and food sources are far more diverse. Many onthophagines have alternative food and nesting habits This includes taxa that feed on carrion, millipedes, fruit, or mushrooms (Hanski and Cambefort 1991, Brühl and Krell 2003). The number of times these alternative food sources have evolved is unknown

Methods

Results

Discussion

Conclusion