A new species of Eopteranodon (Pterodactyloidea, Tapejaridae) from the Lower Cretaceous Yixian Formation of China

The Tapejaridae is an exquisite toothless pterodactyloid clade of pterosaurs that flourished in the Jehol Biota with well-developed premaxillary and dentary crests, large nasoantorbital fenestra and downward rostrum. Since Sinopterus dongi has been reported from the Jiufotang Formation, most of the Chinese tapejarids were discovered from this geological unity. Eopteranodon lii, the first tapejarid from the Yixian Formation, was formerly referred to the Pteranodontidae and is now assigned to the Tapejaridae. Here, Eopteranodon yixianensis sp. nov. is reported from this latter formation as differing from all other known tapejarids by largest rostral value (10.88); the nasoantorbital fenestra is not as long as that of other tapejarids (accounting for 35% of the skull length). Furthermore, the skull's length/height ratio is ∼5.67; the lower bony crest occupies ∼42% of the total mandibular length; the humerus and the fourth wing phalanx length ratio is ∼2.17 and the downturn rostral angle is ∼17°. New data on the evolution (morphology and geographical origin) of the group is also provided.