Phylogenetic placement of the Australian Pharetis, gen. nov., and Spherita, gen. nov., in a revised classification of the circum-Antarctic Moriomorphini (Coleoptera : Carabidae)

Abstract

The carabid beetle tribe Moriomorphini attains a disjunct austral geographical distribution, with member taxa occupying Australia, New Zealand, New Caledonia, the Sundas, southern South America and Polynesia. The group arose in Australia, the area exhibiting the greatest generic diversity for the tribe. In this contribution, two new genera are added to the Australian fauna. Pharetis thayerae, gen. nov., sp. nov., is described from Grenvillia, New South Wales, and Spherita newtoni, gen. nov., sp. nov., is described from Avon Valley National Park, Western Australia. Their phylogenetic placement within the tribe is accomplished by parsimony analysis based on 208 morphological characters across 124 taxa, 114 in-group species and 10 outgroup taxa representing Trechini, Psydrini and Patrobini. Nearly all polytypic moriomorphine genera are represented in the analysis by at least two exemplars, allowing initial tests of generic monophyly. A revised classification is proposed for Moriomorphini, with subtribal clades related as (Amblytelina + (Moriomorphina + Tropopterina)). The Western Australian genus Spherita is placed as adelphotaxon to Sitaphe Moore, a genus restricted to tropical montane Queensland. From the phylogenetic analysis, other non-contemporaneous east–west Australian disjunctions can be inferred, as well as multiple trans-Tasman area relationships between eastern Australia and New Zealand, all proposed to be of Miocene age. Pharetis exhibits a disjunct, trans-Antarctic relationship with Tropopterus Solier, its sister-group, distributed in southern South America. Alternative vicariance-based and dispersal-based hypotheses are discussed for the origin of Tropopterus. A review of the taxonomic development of the tribe illustrates the signal importance of monotypic genera in elucidating biological diversity.