Phylogeny and classification of Rhagionidae, with implications for Tabanomorpha (Diptera: Brachycera)
Authors: KERR PETER H. 
Published: March 2024

This paper updates current knowledge of Rhagionidae and related taxa within the infraorder Tabanomorpha. An estimate of phylogeny for the group is presented, based on 127 morphological characters for 60 ingroup species and molecular characters consisting of 3200+ bp sequences of 28S rDNA for 38 ingroup species. The morphology and molecular datasets are analyzed separately and in a combined analysis, using parsimony, maximum likelihood, and Bayesian methods. Morphological and molecular data, when analyzed separately and in combination, yield similar hypotheses of the evolution within Tabanomorpha. Arthrocerinae (Rhagionidae), Chrysopilinae (Rhagionidae), Rhagioninae (Rhagionidae), Spaniinae (Rhagionidae), Tabanoidea (Pelecorhynchidae, Oreoleptidae, Athericidae, and Tabanidae), and Vermileonidae are recovered consistently. The relationships among the major tabanomorph clades, including Austroleptis Hardy and Bolbomyia Loew, remain weakly supported, however. Rhagionidae are recognized as a monophyletic group of four subfamilies and at least 15 extant genera. The subfamily Spaniinae is defined by a special modification of tergite 9 of the female genitalia, which is shared by members of Omphalophora Becker, Ptiolina Zetterstedt, Spania Meigen, Spaniopsis White, and Symphoromyia Frauenfeld. Litoleptis Chillcott is also placed in this group, however this could not be confirmed because females of this genus were not available. The concept of Omphalophora is clarified and the genus is resurrected from synonymy with Ptiolina. On this basis, several species are newly transferred to Omphalophora; they include O. cinereofasciata (Schummel 1837) n. comb., O. fasciata (Loew 1869b) n. comb., O. majuscula (Loew 1869b) n. comb., and O. nigripilosa (Hardy & McGuire 1947) n. comb. Chrysopilinae is defined by having scale-like setae on the thorax and femur, as in Chrysopilus Macquart, Schizella Bezzi, and Stylospania Frey. Solomomyia Nagatomi is recognized as a new junior synonym of Chrysopilus. Seven new names within the genus Chrysopilus are created for binomials that are preoccupied. These include C. amulus Kerr nom. nov. for C. latifrons Williston 1901 (preoccupied by C. latifrons Bezzi 1898), C. batak Kerr nom. nov. for C. tomentosus Meijere 1924 (preoccupied by C. tomentosus Bigot 1887), C. mawambus Kerr nom. nov. for C. obscuripes Brunetti 1927 (preoccupied by C. obscuripes Speiser 1923), C. meunieri Kerr nom. nov. for C. nagatomii Evenhuis 1994 (preoccupied by C. nagatomii Yang & Yang 1991), C. occidentalis Kerr nom. nov. for C. lucifer Adams 1904 (preoccupied by C. lucifer Walker 1852), and C. amorimi Kerr nom. nov. for C. fascipennis Bromley in Curran 1931 (preoccupied by C. fascipennis (Brunetti 1920)). Chrysopilus sinensis (Yang et al. 1997) n. comb. is transferred from Spatulina Szilády, where this species was originally placed. Arthrocerinae contains a single genus, Arthroceras Williston. Phylogenetic analyses consistently show strong support for a clade consisting of Arthrocerinae, Chrysopilinae, and Spaniinae; most females of these subfamilies have spermathecal duct accessory glands. Spermathecal duct accessory glands are reported here for the first time and are unique in Tabanomorpha. Rhagioninae is the earliest branching subfamily of Rhagionidae. The saw sclerite in the larval mandible may be synapomorphic for this subfamily. Members of Rhagioninae include Atherimorpha White, Desmomyia Brunetti, Rhagio Fabricius, and Sierramyia Kerr gen. nov. Atherimorpha setosus (Philippi 1865) is recognized as a new synonym of Atherimorpha praefica (Philippi 1865) and Neorhagio Lindner 1924 is recognized as a new synonym of Atherimorpha. Sierramyia gen. nov. is erected for two species from Mexico that were originally placed in Neorhagio (type species: Neorhagio caligatus Santos 2006). Rhagina Malloch is recognized as a new synonym of Rhagio. As a result, Rhagio yangi Kerr nom. nov. is created for R. sinensis Yang & Yang 1993a (preoccupied by R. sinensis Yang & Nagatomi 1992, n. comb.). Two enigmatic genera, Bolbomyia Loew and Austroleptis Hardy are retained within their own families, Bolbomyiidae status revised and Austroleptidae, respectively. Alloleptis tersus Nagatomi & Saigusa is incertae sedis within Rhagionoidea. Comments on larval morphology of Tabanomorpha are given in light of this work. A key is given to all families of Tabanomorpha and genera of Rhagionidae. The genera of Austroleptidae, Bolbomyiidae, and Rhagionidae are diagnosed, re-described, and re-classified based on characters and relationships established by the phylogenetic analyses, with a list of included species for each genus. A history of the recent classification of Rhagionidae and related taxa is also provided.