London: Dinosaurs roamed the Earth almost nine million years earlier than previously thought, a new study has suggested.
The study of footprints found in Poland from the early Triassic age indicate that the first dinosaurs emerged a few million years after a species wipeout, called Permian-Triassic
extinction, but were a minor group in the panoply of life.
The footprints, thought to be about 250 million years old, are "the indisputably oldest fossils of the dinosaur lineage", according to an international team which has
named the creature that made the footprints Prorotodactylus.
These early dinosaurs were small, four-footed animals, but over the next 50 million years, their class diversified astonishingly, becoming leviathan herbivores and fleet-footed
carnivores that dominated the planet, the `Daily Mail` said. The palaeontologists from Poland, Germany and the US, said the prints, along with those from two other slightly
younger sites, provided important insight into the origin and early evolutionary history of dinosaurs.
As well as suggesting that the origin of the animals occurred in the immediate aftermath of Permo-Triassic event, they indicate that the earliest dinosaur relatives were very
small animals. Their prints are small -- roughly two to four cms across -- suggesting the creatures were about the size of a domestic cat. They walked on four legs and were very rare compared to contemporary reptiles, the findings suggested.
The scientists, Stephen Brusatte, Grzegorz Niedzwiedzki and Richard J Butler, wrote: "The Polish footprints prompt a substantial extension of early dinosaur history. The dinosauromorph lineage originated by at least the Early Olenekian, within a few million years of the devastating Permo-Triassic mass extinction.
"The narrowing gap between the extinction and the oldest stem dinosaurs raises the intriguing possibility that the dinosauromorph radiation may have been part of the general
recovery from the PTE, not an unrelated event that occurred 10 to 20 million years later as previously considered."
The scientists concluded that the dinosaur radiation was a drawn-out affair, "unexplainable by broad platitudes” The findings have been published in the `Proceedings of the Royal Society B` journal.