powerful jaw and relatively small arms compared to its enormous body

shows some early adaptations

gregorii fit as one of the dominant apex predators in the Chinle Formation ecosystems

Concavenator corcovatus

although no direct evidence has been found in the discovered fossils

Dolichorhynchops osborni Variant:Unprimed powerful jaw and relatively smallDolichorhynchops osborni was a marine reptile belonging to the plesiosaur group, specifically a polycotylid , that lived during the Late Cretaceous period , approximately 9288 million years ago, when the vast Western Interior Seaway covered central North America. Unlike the classic long necked plesiosaurs, Dolichorhynchops had a short neck, a large head, and a streamlined body , making it a fast and highly efficient swimmer. Its size was considerable,