Elmidae

Elmidae, commonly known as riffle beetles, is a family of beetles in the order Coleoptera and superfamily Byrrhoidea, described by John Curtis in 1830. Both adults and larvae live in aquatic environments, typically beneath rocks in swift-moving, shallow riffle sections of streams, where they feed on algae and biofilms. The family comprises more than 150 genera and about 1,500 described species, with the earliest known specimen, from Cenomanian-aged Burmese amber, representing the extinct genus Cretohypsilara. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/