Revision of the austral horse fly tribe Scionini (Diptera: Tabanidae)

The hairy-eyed horse fly tribe Scionini comprises over 280 species and are austral in distribution, occurring in Australia, New Guinea, New Zealand and South America. Most adult females are blood-feeding and can transmit multiple diseases to humans and animals, although both sexes are important pollinators of many plants. The current taxonomy of the tribe is hindered by the limited availability of reliable diagnostic characters, as many genera are often weakly diagnosed by combinations of few morphological characters. Recently, the first quantitative phylogenetic hypothesis for the Scionini was provided using molecular data to demonstrate the well-supported monophyly for the tribe, although the widespread genus Scaptia recovered as wildly paraphyletic and formed a series of monophyletic clades corresponding to either subgenera or previously synonymised genera. This present study formally revises and validates the genera of the Scionini, focusing on the most widespread genus Scaptia. All genera are redescribed, illustrated and included for the first time in an updated diagnostic key to the genera of the tribe. The Scionini are now defined to include 17 genera corresponding to previously standing genera (AnzomyiaLessard, 2012; FidenaWalker, 1850; PityoceraGiglio-Tos, 1896; ScaptiaWalker, 1850; and ScioneWalker, 1850), newly revised genera (LepmiaFairchild, 1969 stat.n.; MyioscaptiaMackerras, 1955 stat.n.; PalimmecomyiaTaylor, 1917 stat.n.; PlinthinaWalker, 1850 stat.n.; PseudomelpiaEnderlein, 1922 stat.n; and PseudoscioneLutz, 1918 stat.n.), newly resurrected genera (ApocamptaSchiner, 1867 stat.n.; CopidaphaEnderlein, 1922 stat.n.; ParoscaEnderlein, 1922 stat.n.; OscaWalker, 1850 stat.n.; and TriclistaEnderlein, 1922 stat.n.) and a novel genus from New Zealand (AotearomyiaLessard, gen.n.). The two morphologically distinct genera CaenopangoniaKröber, 1930 trans.n and GoniopsAldrich, 1892 trans.n. have also been removed from the Scionini and reassigned to the more appropriate tribes Mycteromyiini and Goniopsini Lessard tribe.n., respectively.