Dinos shrank in order to survive evolution

A new study has revealed that shrinking dinosaurs' bodies may have helped the group that became birds to continue surviving evolution.

The scientists from Oxford University and the Royal Ontario Museum estimated the body mass of 426 dinosaur species based on the thickness of their leg bones and found that dinosaurs showed rapid rates of body size evolution shortly after their origins, around 220 million years ago.

However, the study also found that only the evolutionary line leading to birds continued to change size at this rate, and continued to do so for 170 million years, producing new ecological diversity not seen in other dinosaurs.

Dr Roger Benson of Oxford University's Department of Earth Sciences, who led the study, said that dinosaurs aren't extinct; there are about 10,000 species alive today in the form of birds and they wanted to understand the evolutionary links between this exceptional living group, and their Mesozoic relatives, including well-known extinct species like T. rex, Triceratops, and Stegosaurus.

He added that they have found exceptional body mass variation in the dinosaur line leading to birds, especially in the feathered dinosaurs called maniraptorans.

The study was published in PLOS Biology.