In 2015 the rhamphorhynchid Orientognathus chaoyangensis was named by Junchang Lü and colleagues. It’s based on a single, incomplete, semi-articulated specimen that was discovered by a farmer in the Upper Jurassic Tuchengzi Formation in Chaoyang, Liaoning, China. The name translates to “eastern jaw from Chaoyang.”
The only known specimen preserves bones from most of the body including the skull, vertebral column, ribs, wings, and legs. Unfortunately, the specimen was excavated by the farmer, and was damaged in the process.
Most the skull is damaged and hard to interpret, but includes part of the maxilla and quadrate. The only other element of the skull that is clear is the lower jaw. Its tip is toothless, and comes to a point, but not as pronounced as in Rhamphorhynchus. The teeth are widely spaced, and cone shaped, with the rostral-most teeth being directed forward and the teeth farther back being directed up.
Orientognathus was a small pterosaur, with a wingspan of only about 1.1 meters (3.5 feet). Its skeleton was generally similar to Rhamphorhynchus, but is further differentiated by its unique skeletal proportions. Notably, its legs were proportionally longer than in Rhamphorhynchus.
When Orientognathus lived, about 150 million years ago, northeastern China was relatively dry in comparison to the climate there both before and after. The Tuchengzi Formation lies between the Middle Jurassic Tiaojishan Formation, and the Lower Cretaceous Yixian and Jiufotang formations. It lived with the early horned dinosaur Chaoyangsaurus.