On the phylogeny and evolution of Mesozoic and extant lineages of Adephaga (Coleoptera, Insecta)

The relationships of extant and extinct lineages of Adephaga were analysed formally for the first time. Emphasis is placed on the aquatic and semiaquatic groups and their evolution in the Mesozoic. dagger Triadogyrus and dagger Mesodineutus belong to Gyrinidae, the sister group of the remaining families. dagger Triaplidae are the sister group of the following groups (Haliplidae, Geadephaga, Dytiscoidea incl. dagger Liadytidae, dagger Parahygrobiidae and dagger Coptoclavidae [major part]). The lack of a ventral procoxal joint and a very short prosternal process are plesiomorphies of dagger Triaplidae. dagger Coptoclavidae and dagger Timarchopsinae are paraphyletic. dagger Timarchopsis is placed in a geadephagan clade. In contrast to other coptoclavids, its metathorax is close to the condition found in Haliplidae, with a complete transverse ridge and coxae with large plates and free mesal walls. dagger Coptoclavidae s.str., i.e. excl. dagger Timarchopsis, is a dytiscoid subgroup. The mesal metacoxal walls are fused, the coxal plates are reduced, and the transverse ridge is absent. dagger Stygeonectes belongs to this dytiscoid coptoclavid unit and is therefore misplaced in dagger Timarchopsinae. dagger Liadytidae belongs to a dytiscoid subgroup, which also comprises the extant families Aspidytidae, Amphizoidae, Hygrobiidae and Dytiscidae. dagger Parahygrobia is the sister group of Hygrobiidae. The larvae are characterized by a broad gula, the absence of the lacinia, retractile maxillary bases and very long urogomphi set with long setae. dagger Liadytiscinae is the sister group of extant Dytiscidae. There is no support for a clade dagger Eodromeinae and for Trachypachidae incl. dagger Eodromeinae. dagger Fortiseode is nested within Carabidae. The exclusion of fossil taxa has no effect on the branching pattern. The evolution of Adephaga in the Mesozoic is discussed. Possible reasons for the extinction of dagger Coptoclavidae are the rise of teleost fish and the competition of Gyrinidae and Dytiscidae, which possess efficient defensive glands and larval mandibular sucking channels.