Utahraptor ostrommaysi Variant:Hand-painted It also had flexible joints

It also had flexible joints between the upper and lower jaws

probably killing it quickly

The exact cause of their extinction is unknown

y no es casual: este animal es conocido por poseer una de las estructuras bucales más extrañas jamás vistas en un vertebrado

and environmental factors are believed to have contributed to their disappearance

Utahraptor ostrommaysi Variant:Hand-painted It also had flexible jointsUtahraptor ostrommaysi was one of the largest known dromaeosaurids and one of the most representative predators of the Early Cretaceous of North America. Its remains come from the Cedar Mountain Formation in eastern Utah, especially from the Yellow Cat Member, in deposits associated with continental environments of floodplains, river channels, and semi arid ecosystems with seasonal wetlands. Formally described by Kirkland, Gaston, and Burge in 1993,