Theropod dinosaurs like "Tyrannosaurus rex" and "Velociraptor" have had major roles throughout the series. An Advanced hunter gains the ability to hunt the "Triceratops" and the "Velociraptor". The Grik are possible descendants of the dinosaur genus "Velociraptor". Puppeteers worked together to create the "T. rex", "Spinosaurus", and "Velociraptor" movements. In reality, "Velociraptor", like many other maniraptoran theropods, was covered in feathers. The game is playable as either paleontologist Dr. Alan Grant, or a "Velociraptor". Grimlock takes on the alternate form of a white velociraptor (his "Beast Wars" toy). Sexual dimorphism by size is evident in some extinct species such as the velociraptor. A specimen of "Velociraptor" has been found with quill knobs on the ulna. Misidentified Velociraptor osmolskae being labeled Velociraptor mongoliensis. Sereno defined the group as all dromaeosaurids more closely related to "Velociraptor" than to "Dromaeosaurus". This fossil preserves a single "Velociraptor" in the midst of battle against a lone "Protoceratops". Other finds in the area include specimens of "Velociraptor" and eutherian mammals. One particularly famous specimen preserves a "Velociraptor" locked in combat with a "Protoceratops". Before he can do this, he is killed by an escaped "Velociraptor".