What are beetles to rocks and mountains? A phylogenetic investigation of Protodendrophagus (Coleoptera: Silvanidae: Brontini) across the Southern Alps of New Zealand

Abstract

Protodendrophagus is a uniquely alpine genus of the beetle family Silvanidae. Other members of the family are typically lowland, forest-dwellers. Protodendrophagus antipodes Thomas 2003 was described from a male holotype from Nelson National Parks and female paratypes from Kahurangi National Park. Initially, due to low specimen numbers, the paratype specimens were thought to represent sexual dimorphism. The recent discovery of additional specimens indicates that the geologically isolated female paratypes represent a new undescribed species. To test this hypothesis, we employed molecular techniques, specifically phylogenetic analysis of the barcoding region of mtDNA cytochrome c oxidase 1 (CO1), and two ribosomal genes, internal transcribed spacer 2 (ITS2), and the D1-D2 subunit of 28s. After testing the data for sources of conflict such as saturation and non-stationary base composition, Bayesian phylogenies support the genetic separation of the specimens from the Kahurangi area. Additionally, CO1 identifies a third group of genetically divergent Protodendrophagus from the north eastern Marlborough. Based on morphological and molecular data the Kahurangi group is suggested to be a new species, whereas further work including calibration should be conducted to determine the cause of the genetic divergence within the genus.