The structure and evolution of false click-beetle larvae (Coleoptera, Eucnemidae)

Three new taxa are described: Cretacnemis new genus, type species Cretacnemis inexspectatus mew species, Cretacnemis inexpectatus new species (Myanmar Cretaceous resin) and Nematodes luchti new species (Viti Levu, Fiji). The larvae of four genera are described for the first time: Agalba rufipennis (Lea) (Australia), Dromaeoloides parvulus (Bonvouloir) (Australia), Dyscharachthis carinaticeps (Lea) (Australia) and Trigonopleurus rugulosus Bonvouloir (Australia). Four larval types are placed tentatively in genera: Cupressicharis elongatus Muona (Cretaceous Myanmar resin), Entomosatopus sp. (Australia), Onya myee Muona (Australia) and Sarpedon scabrosus Bonvouloir (USA, California). A key to larva of all known Eucnemidae genus level taxa is given. The characters used in the key and their phylogenetic implications are discussed. Although the basal Eucnemidae clades are distinctive both as beetles and larvae, it is stressed that many of their diagnostic larval features are plesiomorphies. The larval character evidence indicates that the subfamily Eucneminae is the sister-group of the subfamilies Melasinae and Macraulacinae combined. The evolutionary success of modern Eucnemidae seems to be a consequence of several key factors: (1) the plasticity of the larval structure allowing different developmental solutions in shifting evolutionary pressures, (2) the unique method of larval locomotion within the substrate, (3) the shift from soil to wood infested by fungi and (4) the ability to use extraoral digestion..Peer reviewe