Palaeontologists identify what is likely to be the oldest known dinosaur specimen, patching a 10-15-million-year hole in dinosaurs' evolutionary history.
It walked on two legs, measured 2-3m in length with a large tail and weighed between 20 and 60kg. The find suggests that many millions of years passed between dinosaurs' first members and their dominance on land.
"It fills a gap between what we previously knew to be the oldest dinosaurs and their other closest relatives," report co-author Paul Barrett, of the Natural History Museum in London, told BBC News. The find shores up the idea that dinosaurs evolved on the southern parts of the supercontinent Pangaea. "There was this big gap in the fossil record where dinosaurs should've been present and this fossil neatly fills that gap." The early evolution of dinosaurs is difficult to unpick, as a rich variety of reptiles were proliferating at the time - and some may even have independently evolved characteristics that are associated with dinosaurs.
It now appears that those creatures shared the southern part of the supercontinent Pangaea - now South America, Africa, Antarctica and Australia - with N parringtoni. "Those animals were the earliest of this group that led up toward dinosaurs," explained Dr. Barrett. "Now this takes dinosaurs back to the right kind of time when those two groups would have split apart from each other." As it closes that evolutionary gap, it shows that dinosaurs did not start out as dominant as they later became. "Dinosaurs start out as a very insignificant group of reptiles - all relatively small animals, relatively rare in comparison with other reptile groups - and it's only a bit later in their history that they suddenly explode and take over as the dominant forms of life for nearly 100 million years" - Barrett said.
Via Dr. Stefan Gruenwald