Phylogeny of the supertribe Nebriitae (Coleoptera, Carabidae) based on analyses of DNA sequence data

Abstract

The phylogeny of the carabid beetle supertribe Nebriitae is inferred from analyses of DNA sequence data from eight gene fragments including one nuclear ribosomal gene (28S), four nuclear-protein coding genes (CAD, topoisomerase 1, PEPCK, and <i>wingless</i>), and three mitochondrial gene fragments (16S + tRNA-Leu + ND1, COI ("barcode" region) and COI ("Pat/Jer" region)). Our taxon sample included 264 exemplars representing 241 species and subspecies (25% of the known nebriite fauna), 39 of 41 currently accepted genera and subgenera (all except <i>Notiokasis</i> and <i>Archileistobrius</i>), and eight outgroup taxa. Separate maximum likelihood (ML) analyses of individual genes, combined ML analyses of nuclear, nuclear protein-coding, and mitochondrial genes, and combined ML and Bayesian analyses of the eight-gene-fragment matrix resulted in a well-resolved phylogeny of the supertribe, with most nodes in the tree strongly supported. Within Nebriitae, 167 internal nodes of the tree (out of the maximum possible 255) are supported by maximum-likelihood bootstrap values of 90% or more. The tribes Notiophilini, Opisthiini, Pelophilini, and Nebriini are well supported as monophyletic but relationships among these are not well resolved. <i>Nippononebria</i> is a distinct genus more closely related to <i>Leistus</i> than <i>Nebria</i>. <i>Archastes</i>, <i>Oreonebria</i>, <i>Spelaeonebria</i>, and <i>Eurynebria</i>, previously treated as distinct genera by some authors, are all nested within a monophyletic genus <i>Nebria.</i> Within <i>Nebria</i>, four major clades are recognized: (1) the <i>Oreonebria</i> Series, including eight subgenera arrayed in two subgeneric complexes (the <i>Eonebria</i> and <i>Oreonebria</i> Complexes); (2) the Nebriola Series, including only subgenus Nebriola; (3) the <i>Nebria</i> Series, including ten subgenera arrayed in two subgeneric complexes, the <i>Boreonebria</i> and <i>Nebria</i> Complexes, with the latter further subdivided into three subgeneric subcomplexes (the <i>Nebria</i>, <i>Epinebriola</i>, and <i>Eunebria</i> Subcomplexes)); and (4) the <i>Catonebria</i> Series, including seven subgenera arrayed in two subgeneric complexes (the <i>Reductonebria</i> and <i>Catonebria</i> Complexes). A strong concordance of biogeography with the inferred phylogeny is noted and some evident vicariance patterns are highlighted. A revised classification, mainly within the Nebriini, is proposed to reflect the inferred phylogeny. Three genus-group taxa (<i>Nippononebria</i>, <i>Vancouveria</i> and <i>Archastes</i>) are given revised status and seven are recognized as new synonymies (<i>Nebriorites</i> Jeannel, 1941 and <i>Marggia</i> Huber, 2014 = <i>Oreonebria</i> Daniel, 1903; <i>Pseudonebriola</i> Ledoux & Roux, 1989 = <i>Boreonebria</i> Jeannel, 1937; <i>Patrobonebria</i> Bänninger, 1923, <i>Paranebria</i> Jeannel, 1937 and <i>Barbonebriola</i> Huber & Schmidt, 2017 = <i>Epinebriola</i> Daniel & Daniel, 1904; and <i>Asionebria</i> Shilenkov, 1982 = <i>Psilonebria</i> Andrewes, 1923). Six new subgenera are proposed and described for newly recognized clades: Parepinebriola Kavanaugh subgen. nov. (type species: <i>Nebria delicata</i> Huber & Schmidt, 2017), Insulanebria Kavanaugh subgen. nov. (type species: <i>Nebria carbonaria</i> Eschscholtz, 1829), Erwinebria Kavanaugh subgen. nov. (type species <i>Nebria sahlbergii</i> Fischer von Waldheim, 1828), <i>Nivalonebria</i> Kavanaugh <b>subgen. nov.</b> (type species: <i>Nebria paradisi</i> Darlington, 1931), <i>Neaptenonebria</i> Kavanaugh <b>subgen. nov.</b> (type species: <i>Nebria ovipennis</i> LeConte, 1878), and <i>Palaptenonebria</i> Kavanaugh <b>subgen. nov.</b> (type species: <i>Nebria mellyi</i> Gebler, 1847). Future efforts to better understand relationships within the supertribe should aim to expand the taxon sampling of DNA sequence data, particularly within subgenera <i>Leistus</i> and <i>Evanoleist</i>us of genus <i>Leistus</i> and the <i>Nebria</i> Complex of genus <i>Nebria</i>.