60,000 species and counting: exploring beetle mega-diversity

Systematics, the branch of science that seeks classification of organisms, is an integral part of evolutionary biology, biogeography and ecology. Over the past year and a half my PhD has focused on the systematics of rove beetles (rovbiller), the most diverse group of organisms in the world, with over 60,000 species described so far. Relationships among rove beetles are still largely unknown and given such huge diversity, a classification of the group is highly desired for several reasons: 1) to prepare them for studies focussing on evolutionary biology, biogeography and ecology and 2) to allow accelerated and meaningful species discovery and description.

During a 3 year PhD it is not easy to study all 60,000 species and therefore my project focusses on the subtribe Amblyopinina, a group of over 400 species mostly found in the south temperate regions of the world (Australia, New Zealand, New Guinea, South Africa and South America). Amblyopinina rove beetles form dominant components of leaf litter and other ground-based habitats in those regions, where they predate on other small insects. In South America and Australia some species have an unusual relationship with mammals, with the beetles occurring in the mammal fur and apparently feeding on the mammal ectoparasites. The distribution of Amblyopinina as well as the evolution of mammal association make them an intriguing group to study. However, before the group can be used for studies of biogeography of evolutionary biology, a stable classification of the subtribe is required. I studied the morphology of adult beetles across the subtribe to infer relationships among genera and species. The results indicate the misplacement of many species in incorrect genera, and several new genera and many new species that must be described in due course. Based on existing knowledge I was able to describe two new species from Lord Howe Island and also review the biogeography of the island, in the context of rove beetle diversity. Furthermore, our growing knowledge of Amblyopinina allowed us to describe a remarkable and rare new genus and species, Devilleferus brunkei, from the tropical Andes of South America. We investigated its phylogenetic placement within the tribe Staphylinini based on morphological data resulting in its placement in Amblypoinina. Molecular (DNA) data is currently being gathered to further investigate the classification of the group and to provide a baseline for a future dated phylogeny which may be used to answer all manner of questions.