Coptoclavidae

Coptoclavidae is an extinct family of aquatic beetles in the suborder Adephaga. The Coptoclavidae lived from the Late Triassic to the Early Cretaceous. Coptoclavidae is a member of the adephagan clade Dytiscoidea, which contains living aquatic beetles, including living predatory diving beetles (Dytiscidae). Coptoclavids are thought to have hunted on the water surface, similar to whirligig beetles (Gyrinidiae), with prey likely including small fish and larval amphibians. Suggested reasons for their extinction to include the rise of teleost fish, or competition with Gyrinidae and Dytiscidae, which possess defensive secretions and sucking channels in the mandibles of larvae, which coptoclavids likely lacked. It has been suggested that the genus Timarchopsis and the subfamily Timarchopsinae are only distantly related to other coptoclavids based on cladistic analysis, with Timarchopsis being more closely related to geadephagans like carabids and trachypachids instead. Another study also suggested similarly for Coptoclavisca and possibly other coptoclaviscines. A 2025 study suggested that Coptoclavidae as a whole, as well as most of the major subfamilies, were likely not monophyletic, but represent a number of separate lineages of dytiscoid beetles.