The earliest byrrhoids (Coleoptera, Elateriformia) from the Jurassic of China and their evolutionary implications

The infraorder Elateriformia is crucial for understanding of basal beetles evolution from extraordinarily diverse Polyphaga suborder. However early stages of Elateriformia evolutionary history are far from being studied comprehensively. Here we describe a new genus and species, Serecoleus nadbitovae gen. et sp. nov., from the Middle Jurassic of Daohugou, northeastern China. S. nadbitovae clearly belongs to Byrrhoidea, but is different from all known families based on the combination of following characters: shallow longitudinal frontal depression between eyes; obliterated frontoclypeal suture; presence of wide membranous area (basal membrane) between frontoclypeus and free labrum; mandibles with pointed, sickle-shaped apices; subtriangular mentum and praementum with median groove; elytra with fine punctures arranged in rows. S. nadbitovae sp. nov. is compared with similar contemporaneous species and the relationship with those fossils, as well as with extant taxa, is discussed. More remarkably, our finding proves the basal taxonomic position of Byrrhoidea.