The oldest osoriine rove beetle from Cretaceous Burmese amber (Coleoptera: Staphylinidae)

A remarkable new genus and species, Mesallotrochus longiantennatus n. gen. n. sp., is described and figured based on a well-preserved individual in the lowermost Upper Cretaceous (Cenomanian) amber from Myanmar. Mesallotrochus is placed in the extant tribe Thoracophorini based on its general habitus, including the protibia with inner edge straight, without ctenidium, exposed protrochantins, open procoxal cavities, and more or less flatted body. Mesallotrochus is separated from other allied genera by the long antennae, very long maxillary palpomere 4, contiguous procoxae, and well-developed anterolateral pronotal angles. The new discovery of the oldest Osoriinae from about 99 million years not only suggests the antiquity of the subfamily, but also bears significant biogeographic implications.