Phylogeny of Bembidion and related ground beetles (Coleoptera: Carabidae: Trechinae: Bembidiini: Bembidiina)

摘要

The phylogeny of the large genus Bembidion and related genera is inferred from four nuclear protein-coding genes (CAD, wingless, arginine kinase, and topoisomerase I), ribosomal DNA (28S and 18S), and the mitochondrial gene cytochrome oxidase I (COI). 230 of the more than 1200 species of Bembidion are sampled, as well as 26 species of five related genera, and 14 outgroups. Nuclear copies (numts) of COI were found sparsely scattered through sampled species. The resulting phylogeny, based upon individual gene analyses and combined analyses using maximum likelihood and parsimony, is very well supported at most nodes. Additional analyses explored the evidence, and corroborate the phylogeny. Seven analyses, each with one of the seven genes removed from the combined matrix, were also conducted, and yielded maximum likelihood bootstrap trees sharing over 92% of their nodes with the original, well-resolved bootstrap trees based on the complete set of seven genes. All key nodes were present in all seven analyses missing a single gene, indicating that support for these nodes comes from at least two genes. In addition, the inferred maximum likelihood tree based on the combined matrix is well-behaved and self-predicting, in that simulated evolution of sequences on the inferred tree under the inferred model of evolution yields a matrix from which all but one of the model tree's clades are recovered with bootstrap value >50, suggesting that internal branches in the tree may be of a length to yield sequences sufficient to allow their inference. All likelihood analyses were conducted under both a proportion-invariable plus gamma site-to-site rate variation model, as well as a simpler gamma model. The choice of model did not have a major effect on inferred phylogenies or their bootstrap values. The inferred phylogeny shows that Bembidarenas is not closely related to Bembidiina, and Phrypeus is likely distant as well; the remaining genera of Bembidiina form a monophyletic group. Lionepha, formerly considered a subgenus of Bembidion, is shown to be outside of the clade of Asaphidion+. Bembidion, and is separated as its own genus. B. (Phyla) obtusum is quite isolated within Bembidion, and there is some evidence that the remaining Bembidion form a clade. Within Bembidion, there are three large clades that are well-supported, the Bembidion, Odontium, and Ocydromus Series. The Bembidion Series contains Bembidion (s. str.), Notaphus, Furcacampa, Emphanes, Trepanedoris, Diplocampa, and related Holarctic species; all species from South America, Australia, New Zealand; and most species from southern Africa and Madagascar. All species in South America, except for members of Notaphus and Nothocys, form a clade, the Antiperyphanes Complex, which has independently radiated into body forms and niches occupied by multiple, independent Northern-Hemisphere forms. All species from New Zealand, including Zecillenus, and Australian species formerly placed in Ananotaphus together form a clade. Bembidion (s. str.) and Cyclolopha are in a clade with the Old World, Southern Hemisphere lineages Notaphocampa, Sloanephila, and Omotaphus. The large subgenus Notaphus appears to have originated in South America, with all Northern Hemisphere Notaphus arising from within a south-temperate grade. All major variation in frontal furrows on the head is contained within the Bembidion Series. The Odontium Series contains subgenera Hirmoplataphus and Hydriomicrus, which together are the sister clade of Odontium, Bracteon, Ochthedromus, Pseudoperyphus, and Microserrullula. The very large Ocydromus Series, dominant in the Holarctic region, includes the Ocydromus Complex, with many subgenera, including Hypsipezum and Leuchydrium; the phylogeny within this group is notably at odds with the current classification. Also included in the Ocydromus Series are Nepha and Bembidionetolitzkya, as well as the Princidium Complex, in which the intertidal B. (Cillenus) laterale falls.