The discovery of a dog-sized dinosaur in North America was made during the Late Cretaceous period.

Dr. Nick Longrich from the University of Bath’s Milner Centre for Evolution, England, has identified a dinosaur that measured in at least a dog. This rare fossil is evidence that North American dinosaur evolution took place east to west. The North American land mass was divided by a shallow ocean during the Late Cretaceous period (66 up to 100 millions years ago. The Western Interior Seaway, a shallow sea that ran from the Arctic Ocean up to the Gulf of Mexico was the Western Interior Seaway. Laramida is the name given to dinosaurs who lived on the west continent. They were very similar to those that lived in Asia. One of the leptoceratopsids was a dog-sized dinosaur. It had a narrow, beaked-shaped jaw that suggested a different diet from its western cousins. Because the region is so densely covered in vegetation, it has proven difficult to locate fossilized species from Appalachia’s eastern “lost continent”. One of the rare fossils Longrich examined was a fragment from a jaw kept by Yale University’s Peabody Museum. It was likely a Ceratopsia member, he said. His findings were published in Cretaceous Research by Dr. Longrich. Ceratopsia was a plant-eating dinosaur Ceratopsia lived in the Cretaceous period. Dr. Longrich examined the fossil of the lesser-known Triceratops, the leptoceratopsids. The fossil was roughly the same size as a German shepherd dog. Although the fossil was not complete enough to determine the species, Dr. Longrich noticed a peculiar twist in the jaw that caused the teeth to bend outwards, and then downwards, creating a beak shape. The jaw was shorter than those found in Ceratopsia, western North America. These dinosaurs likely had different diets than their western counterparts and were therefore on a different evolutionary track. The Late Cretaceous period saw North America look very different. Appalachia was home to the dog-sized dinosaur. Dr. Longrich stated that the dog-sized dinosaur was found in Appalachia. Many land masses, including Australia, Europe, Africa and South America at the time were separated by water. Cretaceous Research Volume 57, January 2016, Pages DOI: 10.1016/j.cretres.2015.08. 004.