Megolisthaerus chinensis gen. et sp.n. (Coleoptera: Staphylinidae incertae sedis): an enigmatic rove beetle lineage from the Early Cretaceous

A remarkable extinct rove beetle, Megolisthaerus chinensis Solodovnikov & Yue, gen. et sp.n., from the Yixian Formation (some 125-121 million years ago) in China is described. The new taxon displays a very puzzling combination of morphological characters, some of which are insufficiently preserved for unambiguous interpretation. As a result, Megolisthaerus chinensis cannot be clearly assigned to any of the hitherto described subfamilies of Staphylinidae. Based on the evaluation of the available morphological characters, it seems to be either a member of, or closely related to, the recent subfamilies Olisthaerinae and Phloeocharinae, together forming a loosely defined lineage within the Tachyporine-group of subfamilies. Megolisthaerus chinensis is a remarkable species that shows that the phylogenetic structure of Staphylinidae in Early Cretaceous might have been significantly different from the one displayed by the recent fauna of this enormously diverse family. It is possible that Megolisthaerus manifests an extinct group of supra-generic rank that, naturally, cannot be classified within the current system of the family that is based on the study of recent lineages.