A new coptoclavid larva (Coleoptera: Adephaga: Dytiscoidea) from the Middle Jurassic of China,and its phylogenetic implication

Daohugounectes primitivus, a new genus and species of coptoclavid beetles, is described from 67 fossil larvae from the Jurassic locality of Daohugou, northeastern China. It differs from other coptoclavids in the combination of the following characters: lateral lobes of nasale present; legs relatively short, with tarsi flat and slightly dilated; abdominal tergite VIII almost circular; derivative of abdominal segment IX present; urogomphi short; and helical thickening of tracheae weak. Most of these features are plesiomorphic for the family Coptoclavidae and the superfamily Dytiscoidea. Among dytiscoids, a derivative of abdominal segment IX is present only in the larvae of the recently discovered relic family Aspidytidae.