The discovery of a new species of dromaeosaurid -- a family of generally small to medium-sized feathered carnivores that lived during the Cretaceous Period -- is reported in Scientific Reports this week. The fossil furthers our understanding of dinosaur evolution during the Late Cretaceous (70-68 million years ago).
Steven Jasinski and colleagues discovered 20 identifiable skeletal elements of the new dromaeosaurid in deposits of the Ojo Alamo Formation in the San Juan Basin, New Mexico, USA. The dinosaur has been named Dineobellator notohesperus from the Navajo word Diné (Navajo people) and the Latin word bellator (warrior). The authors report a number of unique features, including vertebrae near the base of the tail that curved inwards, which could have increased Dineobellator's agility and improved its predation success. A gouge mark on the fossil's large sickle-shaped claw may have been inflicted during an altercation with another Dineobellator or other theropod such as Tyrannosaurus rex, they speculate.
Phylogenetic analyses of relationships between species suggest that Dineobellator may be part of the Velociraptorinae subfamily, which also includes velociraptors. Ancestors of Dineobellator are thought to have migrated from Asia to North America where multiple lineages may have evolved, potentially accounting for differences in morphology between Dineobellator and other dromaeosaurids.
The findings, which contribute to the sparse fossil record of dromaeosaurids, indicate that this family was still diversifying at the end of the Cretaceous period prior to the mass extinction that wiped out non-avian dinosaurs 65.5 million years ago.