Detecting the basal dichotomies in the monophylum of carrion and rove beetles (Insecta: Coleoptera: Silphidae and Staphylinidae) with emphasis on the Oxyteline group of subfamilies

Carrion beetles (Silphidae) and rove beetles (Staphylinidae, including Scaphidiinae, Pselaphinae and Scydmaeninae) form a well supported and exceptionally species-rich clade with nearly 58,000 described Recent species (of them Silphidae constitute0.3%). The presently accepted classification implies a sister-group relationship between these families. The enormous clade of Staphylinidae, if indeed monophyletic, has its basal-most dichotomies inadequately hypothesized. We analysed 240parsimony-informative larval and adult morphological characters for 34 terminals of carrion (3) and rove beetles (31) and rooted the obtained topologies on Neopelatops (Leiodidae). The most fully resolved topologies from the combined datasetconsistently suggest that carrion and rove beetles are indeed monophyletic sister-groups. Two ancient species-poor rovebeetle subfamilies (Apateticinae with two genera in the eastern Palaearctic, and the monogeneric Holarctic Trigonurinae)branch off as a clade from the rest of Staphylinidae, rather than with members of the Oxyteline Group. Subsequent dichotomies of the staphylinid main clade remain obscure. A newly redefined and monophyletic Oxyteline Group is formed byScaphidiinae + (Oxytelinae + Osoriinae + Piestinae), the last subfamily paraphyletic with respect to the previous two, which are monophyletic. The Oxyteline Group and the earlier detected monophyletic Omaliine and Staphylinine Groups form threemain subdivisions within the rove beetles. Their interrelationships, as well as those with the possibly monophyletic Tachyporine Group (which includes the mega-diverse Aleocharinae), form the main unresolved questions in basal Staphylinidaephylogeny.