An exquisitely preserved troodontid theropod with new information on the palatal structure from the Upper Cretaceous of Mongolia

Takanobu Tsuihiji, Rinchen Barsbold, Mahito Watabe, Khishigjav Tsogtbaatar, Tsogtbaatar Chinzorig, Yoshito Fujiyama, Shigeru Suzuki

Troodontidae is a clade of small-bodied theropod dinosaurs. A new troodontid, Gobivenator mongoliensis gen. et sp. nov., is described based on the most complete skeleton of a Late Cretaceous member of this clade presently known, from the Campanian Djadokhta Formation in the central Gobi Desert. G. mongoliensis is different from other troodontids in possessing a pointed anterior end of the fused parietal and a fossa on the surangular in front of the posterior surangular foramen. The skull was superbly preserved in the specimen and provides detailed information of the entire configuration of the palate in Troodontidae. Overall morphology of the palate in Gobivenator resembles those of dromaeosaurids and Archaeopteryx, showing an apparent trend of elongation of the pterygoid process of the palatine and reduction of the pterygopalatine suture toward the basal Avialae. The palatal configuration suggests that the skull of Gobivenator would have been akinetic but had already acquired prerequisites for later evolution of cranial kinesis in birds, such as the loss of the epipterygoid and reduction in contact areas among bones.