Fossils May Be Oldest Dinosaurs Ever Discovered

Fossils from two calf-sized animals that lived in a period before the Jurassic are thought to be the oldest dinosaur remains ever found and may be from a group that helped begin the age of the dinosaurs, researchers say.

A team from UC Santa Barbara and three other institutions uncovered the fossils in an ancient riverbed in Madagascar and found that they were mixed with the remains of animals known from earlier studies to have lived 227 million years ago.

Andre Wyss of UC Santa Barbara, co-founder of the research team, said the fossils are “probably the earliest dinosaurs known from anywhere in the world.”

A report on the fossil find appears today in the journal Science.

The dating of the fossils is based on the nearby discovery of bones from primitive forms of other animals, including a mammal-like reptile, that are known to have lived just before the age of dinosaurs. An earlier dinosaur find in Argentina included more advanced forms of the mammal-like reptiles and has been dated using radioisotopes at 227 million years, Wyss said.

“We know we are earlier than 227 million years, and these animals could be as much as 5 million years older,” he said.

The new specimens consist of the upper and lower jawbones of two dinosaur species never before seen, Wyss said. Based on the teeth and the characteristics of the jaws, the researchers believe the animals are prosauropods, primitive plant-eaters with small heads and long necks. The apatosaurus, a 36-ton monster that was among the largest animals ever to walk the Earth, is thought to have descended over millions of years from the prosauropods.

“That was the animal that Fred Flintstone rode,” Wyss joked.

Wyss said the fossils come from an immense collection that is still being analyzed and dug out of quarries in Madagascar. The researchers will not name the new animal species until more is known about it, he said.

Neil Shubin, a dinosaur researcher at the University of Pennsylvania, said experts may argue about the age of the new specimens because it has not been established by the accurate radioisotope method.

“Whether you want to call this the earliest dinosaur or one of the earliest dinosaurs depends upon your interpretation,” he said.