First Mesozoic water-penny beetles from Upper Cretaceous Burmese amber (Coleoptera: Psephenidae)

Psephenidae (water-penny beetles) is a small group of byrrhoid beetles, well known for their specialized larval form. Fossil psephenids are usually known as larvae from the Cenozoic deposits. Here we describe and figure the first Mesozoic psephenid, Vetujinbrianax cretaceus gen. et sp. nov., based on a well preserved adult from the Upper Cretaceous Burmese amber. Vetujinbrianax can be placed in the extant subfamily Eubrianacinae, and it has a close affinity to the Oriental genus Jinbrianax based on the presence of plesiomorphic characters such as short prosternal process and paired tibial apical spurs. V. cretaceus represents the oldest fossil record of Eubrianacinae, as well as the first definitive adult fossil of Psephenidae.