The oldest known riffle beetle (Coleoptera: Elmidae) from Early Cretaceous Spanish amber

Elmadulescens rugosus Peris, Maier et Sánchez-García n. gen. n. sp. is described based on a single specimen from Spanish amber (El Soplao outcrop, Early Albian, Early Cretaceous). The discovery of this specimen in amber is very interesting, since aquatic beetles are not common in fossil tree resin. This fossil pushes back the oldest known specimen of Elmidae from the Eocene (∼ 40 Ma) to at least the Early Cretaceous (∼ 110 Ma).