October 21, 2016:

The characters of Tapejaridae are summarized. Especially, the Chinese toothless pterosaurs (including tapejarids, chaoyangopterids and azhdarchids) are systematically summarized. Based on the comparison, the Chinese tapejarids are divided into two new subfamilies: Sinopterinae and Huaxiapterinae. From the morphological changes of the tapejarid skulls, the evolution trend of skulls is from long and shallow to short and high, these changes may be caused by their diet changes. A new species of Sinopterinae: Sinopterus lingyuanensis sp. nov. is erected based on the nearly complete skeleton from the Jiufotang Formation of Sihedang, Lingyuan of Liaoning Province. Sinopterus lingyuanensis sp. nov. is characterized by ratio of length to height of nasoantorbital opening approximate 3.20; rostral index 3.03; length ratio of femur to tibia approximate 0.66 and ratio of wing phalange 2 to wing phalange 1 about 0.85. A new species of huaxiapterid pterosaur: Huaxiapterus atavismus sp.nov. is erected based on a small tapejarid skeleton from the Jiufotang Formation of Chaoyang, western Liaoning Province. Although it is small, it bears a premaxillary crest which is one character of huaxiapterids. However, Huaxiapterus atavismus differs from other huaxiapterids in that a groove appears on the posterior surfaces of the wing phalange 2 and wing phalange 3 respectively, and this character only appears in those primitive rhamphorhynchid pterosaurs. The groove like structure, which appears in Huaxiapterus atavismus should be the reflection of atavism. This phenomenon is the first reported in pterodactyloids.

LÜ Junchang, TENG Fangfang, SUN Deyu, SHEN Caizhi, LI Guoqing, GAO Xia & LIU Hanfeng (2016)
The Toothless Pterosaurs from China.
Acta Geologica Sinica 90(9): 2513-2525 (Chinese edition)