Washington. The herbivorous dinosaurs likely arrived in the northern hemisphere after millions of years of their carnivorous cousins, a delay that could result from climate change, according to a new study.
A new method for estimating the ages of dinosaur fossils found in Greenland suggests that the herbivores, called sauropodomorphs, were about 215 million years old, according to the study published in Measures , From the US National Academy of Sciences. They were previously thought to be around 228 million years old.
This information changes the way scientists think about dinosaur migration.
The first dinosaurs first appeared to have evolved in what is now South America about 230 million years ago or more. Then they turned north and spread across the planet. The new study indicates that not all dinosaurs were able to migrate at the same time.
So far, scientists have not found a single example of the oldest family of herbivorous dinosaurs in the Northern Hemisphere that is more than 215 million years old. One of the best examples of this is the Plateosaurus, which is a botanical seven meters high and weighing about four tons.
However, scientists say there were carnivorous dinosaurs worldwide for at least 220 million years, according to Randy Eremis, a University of Utah paleontologist who was not part of the study.