Taxonomy of the Australian Allodapine Bee Genus Exoneurella (Apidae: Xylocopinae: Allodapini) and Description of a New Exoneurella Species

The taxonomic status of lineages within the Australian allodapine bees has been unstable over the last six decades, with multiple changes in generic and subgeneric assignments. This is unhelpful given the continuing attention to these bees for understanding social evolution and biogeography. The Australian genus Exoneurella (Michener, 1963 Hymenoptera: Apidae) has received substantial attention because it contains a highly eusocial species, Exoneurella tridentata (Houston, 1976), as well as casteless species. Here, we describe a new Exoneurella species Exoneurella micheneri sp. nov. With the addition of this species, and re-examination of the four other Exoneurella species, we redefine the genus and use both genetic and morphological data to explore its phylogenetic relationships to the other Australian allodapine genera. We show that E. tridentata is highly unusual, not just in terms of queen/worker morphology but also in terms of male genitalia. As with other allodapine genera, larval morphology is highly divergent between genera, while female morphology is more conserved.