[D] Koparion douglassi [sG] [T]
Saurischia Theropoda Tetanurae Coelurosauria Maniraptora ?Troodontidae
Morrison Formation, of Dinosaur National Monument, US
Genus - Typespecies
The indentification of teeth (Koparion - large triangle) as those of troodontids from the Upper Jurassic Morrison Formation would be more convincing if diagnostic postcranial elements would be discovered. Basal ornithomimosaurs and other theropods can have troodont-like teeth. However given the highly derived nature of Early Cretaceous troodontids, it is not unlikely that the family traces its origins back into the Jurassic.