The fossils push back the dawn of the dinosaurs to around 240 million years ago—about 10 to 15 million years earlier than previously thought, scientists say.

Dubbed Nyasasaurus parringtoni, the animal is only known from an upper arm and some back bones discovered in Tanzania in the 1930s but only recently studied in detail.

Prior to the new analysis, the oldest known dinosaur fossils belonged to small, lightly built, meat-eating creatures found in South America that dated to around 230 million years ago.

(See pictures: "Oldest Dinosaur Nests Found in South Africa.")

Very little is known about Nyasasaurus. Based on the fossils, scientists estimate it was between 6.5 to 10 feet (2 to 3 meters) long, including its tail. But no skull