New material of a troodontid theropod (Dinosauria: Saurischia) from the Lower Cretaceous of Mongolia

New material of a troodontid theropod from Khamaryn Ar in Mongolia, representing the second troodontid specimen described from the Lower Cretaceous of the Gobi Basin, is reported. This material consists mainly of caudal, manual and pedal bones, and can be assigned to Troodontidae based on the presence of derived features such as distal caudals bearing sulci on neural arches instead of neural spines, asymmetrical pes with slender metatarsal II and robust metatarsal IV, and pedal phalanx II-2 with the distal articular surface less than half the size of the proximal surface. The present specimen is considered merely as Troodontidae gen. et sp. indet. because of the lack of definitive autapomorphies. The present finding suggests that further exploration of the Lower Cretaceous in the Gobi Basin may still provide much new information on the theropod fauna in this region.