Phylogenetic analysis of Adephaga (Coleoptera) with extensive taxon sampling reveals unexpected relationships within the hyperdiverse beetle subfamily Harpalinae (Carabidae)

Beetles of the family Carabidae comprise one of the larger families of Coleoptera, yet their higher-level phylogeny has remained poorly resolved. We present a taxonomically densely sampled molecular phylogenetic analysis of Adephaga, with emphasis on Carabidae and its hyperdiverse and most problematic subfamily, Harpalinae. Our dataset includes 529 carabid species and 101 other adephagan species; sequence data comprises five nuclear gene fragments. We sample nearly all notable carabid lineages, including obscure and phylogenetically enigmatic genera. Our results provide an improved framework of carabid phylogenetic relationships. We recover well-supported placements for numerous lineages not previously included in molecular analyses, document several cases of non-monophyly among long-recognized tribes, and identify several unexpected but consistently recovered relationships within Harpalinae. Enigmatic groups such as Geobaenini, Amorphomerini, Idiomorphini, and Agonicina, which had not previously been included in a molecular phylogenetic analysis, are placed, suggesting or clarifying their affinities and revealing previously unrecognized clades. Some traditionally recognized taxa, including Pterostichini, Morionini and Oodini, show strong or moderate evidence of non-monophyly. Based on these results, we propose a revised classification of Carabidae to tribal level. We further re-examine various morphological character evidence to reassess hypotheses of character state evolution and to identify morphological synapomorphies relevant to both extant and fossil taxa. Together, dense taxon sampling, multilocus molecular data, and renewed integration of morphology provide a stable and testable hypothesis of carabid relationships, and a foundation for future evolutionary research and classification of one of the most diverse lineages of beetles.