Here we present a phylogeny of beetles (Insecta: Coleoptera) based on DNA sequence data from eight nuclear genes, including six single-copy nuclear protein-coding genes, for 367 species representing 172 of 183 extant families. Our results refine existing knowledge of relationships among major groups of bee- tles. Strepsiptera was confirmed as sister to Coleoptera and each of the suborders of Coleoptera was recovered as monophyletic. Interrelationships among the subor- ders, namely Polyphaga (Adephaga (Archostemata, Myxophaga)), in our study differ from previous studies. Adephaga comprised two clades corresponding to Hydrade- phaga and Geadephaga. The series and superfamilies of Polyphaga were mostly monophyletic. The traditional Cucujoidea were recovered in three distantly related clades. Lymexyloidea was recovered within Tenebrionoidea. Several of the series and superfamilies of Polyphaga received moderate to maximal clade support in most analyses, for example Buprestoidea, Chrysomeloidea, Coccinelloidea, Cucujiformia, Curculionoidea, Dascilloidea, Elateroidea, Histeroidea and Hydrophiloidea. However, 836 D. D. McKenna et al. many of the relationships within Polyphaga lacked compatible resolution under maximum-likelihood and Bayesian inference, and/or lacked consistently strong nodal support. Overall, we recovered slightly younger estimated divergence times than pre- vious studies for most groups of beetles. The ordinal split between Coleoptera and Strepsiptera was estimated to have occurred in the Early Permian. Crown Coleoptera appeared in the Late Permian, and only one or two lineages survived the end-Permian mass extinction, with stem group representatives of all four suborders appearing by the end of the Triassic. The basal split in Polyphaga was estimated to have occurred in the Triassic, with the stem groups of most series and superfamilies originating during the Triassic or Jurassic. Most extant families of beetles were estimated to have Creta- ceous origins. Overall, Coleoptera experienced an increase in diversification rate com- pared to the rest of Neuropteroidea. Furthermore, 10 family-level clades, all in suborder Polyphaga, were identified as having experienced significant increases in diversification rate.These include most beetle species with phytophagous habits, but also several groups not typically or primarily associated with plants. Most of these groups originated in the Cretaceous, which is also when a majority of the most species-rich beetle families first appeared. An additional 12 clades showed evidence for significant decreases in diversi- fication rate. These clades are species-poor in theModern fauna, but collectively exhibit diverse trophic habits. The apparent success of beetles, as measured by species numbers, may result from their associations with widespread and diverse substrates – especially plants, but also including fungi, wood and leaf litter – but what facilitated these associ- ations in the first place or has allowed these associations to flourish likely varies within and between lineages.Our results provide a uniquelywell-resolved temporal and phylo- genetic framework for studying patterns of innovation and diversification in Coleoptera, and a foundation for further sampling and resolution of the beetle tree of life.
The family Buprestidae (jewel beetles or metallic wood-boring beetles), contains nearly 15000 species in 522 genera. Together with the small family Schizopodidae (seven species, three genera), they form the superfamily Buprestoidea. Adult Buprestoidea feed on flowers or foliage, whereas larvae are mostly internal feeders, boring in roots or stems, or mining the leaves of woody or herbaceous plants. The subfamilial and tribal classification of Buprestoidea remains unsettled, with substantially different schemes proposed by different workers based on morphology. Here we report the first large-scale molecular phylogenetic study of the superfamily Buprestoidea based on data from four genes for 141 ingroup species. We used these data to reconstruct higher-level relationships and to assess the current classification and the origins of the larval leaf-mining habit within Buprestoidea. In our analyses, the monophyly of Buprestoidea was strongly supported, as was the monophyly of Schizopodidae and its placement sister to Buprestidae. Our results are largely consistent with the generally accepted major lineages of buprestoids, including clearly-defined agrilines, buprestines-chrysochroines and early-branching julodines-polycestines. In addition to Schizopodidae, three of the six subfamilies were monophyletic in our study: Agrilinae, Julodinae and the monogeneric Galbellinae (Galbella). Polycestinae was monophyletic with the exception of the enigmatic Haplostethini. Chrysochroinae and Buprestinae were not monophyletic, but were recovered together in a large mixed clade along with Galbella. The interrelationships of Chrysochroinae and Buprestinae were not well resolved; however they were clearly polyphyletic, with chrysochroine genera falling into several different well-supported clades otherwise comprising buprestine genera. All Agrilinae were contained in a single strongly supported clade. Coraebini were dispersed throughout Agrilinae, with strong nodal support for several clades representing subtribes. Neither Agrilini nor Tracheini were monophyletic. The leaf-mining genus Paratrachys (Paratracheini) was recovered within the Acmaeoderioid clade, consistent with the current classification, and confirming the independent origins of leaf-mining within Polycestinae and Agrilinae. Additionally, our results strongly suggest that the leaf-mining agriline tribe Tracheini is polyphyletic, as are several of its constituent subtribes. External root feeding was likely the ancestral larval feeding habit in Buprestoidea. The apparent evolutionary transitions to internal feeding allowed access to a variety of additional plant tissues, including leaves. Interestingly, the several genera of leaf-mining agrilines do not form a monophyletic group. Many of these genera are diverse and highly specialized, possibly indicating adaptive radiations.