A British-based researcher has identified the skeletal remains of a horned dinosaur that was recovered from eastern North America and kept at Yale University.
Dr. Nick Longrich, a dinosaur expert from the University of Bath's Milner Centre for Evolution examined a jawbone fragment of a dog-sized dinosaur that was being stored at Yale's Peabody Museum.
He identified the remains as that of a Ceratopsia, a creature that existed during the Late Cretaceous era, around 66 million to 100 million years ago.
Before the formation of what is now known as the present-day continent of North America, it used to be part of a large mass of land that was populated by different kinds of dinosaurs.
However, this larger continent was later split into two by the Western Interior Seaway, which ran from the Arctic Ocean to the Gulf of Mexico.
During this drastic shift in land mass, the dinosaur inhabitants were separated as well. Those that were caught in the western part of the continent are called Laramidia.
Creatures that were caught in the eastern portion, however, remained largely unidentified because of the high vegetation in the region that kept scientists from recovering their fossils.
The jawbone fragment that Longrich examined is considered to be the first fossil of such dinosaur from the Late Cretaceous era ever to be recovered from North American's eastern part.
Ceratopsia
Ceratopsian dinosaurs were a group of horned herbivore creatures that mostly lived during the Cretaceous era. The skeletal remains that were kept in Yale belonged to relatively smaller relative of Triceratops known as leptoceratopsids.
While the fossil specimen allowed Longrich to identify the dinosaur group the creature was a part of, it was not enough to provide him with information on its exact species. One distinguishable trait of the jaw fragment was its unusual twist that caused the creature's teeth to curve downward and protrude similar to a beak.
It was also considerably more slender compared to jaws recovered from Ceratopsian dinosaur unearthed in North America's western portion. This suggests that these creatures had a different diet than their western counterparts and followed their own evolutionary path.
Longrich explained that just like how a number of plants and animals in Australia are different from those in other countries in the world, creatures that existed in North America's eastern portion during the Late Cretaceous also had a completely different evolutionary history compared to those that lived in the continent's western portion.
He said this supports earlier assumptions that these two masses of land used to be one massive continent that was separated by the Western Interior Seaway.
This prohibited creatures from moving between the two newer continents and caused the dinosaurs caught in the eastern part to follow an entirely different evolutionary path.
The findings of the University of Bath study are featured in the journal Cretaceous Research.
