Friday, October 22, 1999 Published at 14:50 GMT 15:50 UK
Dinosaur discovery claims record
Madagascar is regarded as a dino treasure trove
Scientists have unearthed what they believe to be the oldest dinosaurs discovered.
Fossil experts say the creatures are both prosauropods, creatures with small heads and long necks. They could walk on two or four legs and they ate only plants. Their remains were found in Madagascar.
The remains of eight other prehistoric creatures were uncovered with the prosauropods. The discovery is exciting because the fossils date from a period in Earth's history scientists know very little about.
Now palaeontologists have discovered an area in Madagascar stretching over more than 1,000 kilometres that they hope will give up some of that period's secrets. They were led to the location by a young, local man called Mena who had found what he thought were old bones.
"The fossils are exquisitely preserved. They show a level of detail far superior to everything else from that time," says John Flynn, of the Field Museum in Chicago, and one of a large team of scientists currently working on the project.
Of the eight animals discovered in addition to the prosauropods, three are members of the branch of animals that includes modern-day reptiles and five are members of the branch that includes mammals. Most of the eight animals have never been seen before.
The team were unable to use radiocarbon dating to age the fossils because of the nature of the rock in Madagascar. Instead, they had to use other clues to date their finds, for example, by analysing the distribution and anatomy of other fossils in the rock strata.
The Madagascar fossil record is suspiciously lacking in fossils of aetosaurs - small, armored reptilian herbivores that were abundant about 228 million years ago. The team have therefore concluded that their find is more ancient - probably closer to 230 million years old - making the two new prosauropods the oldest dinosaurs ever discovered.
The paleontologists also expect that their find will provide clues as to how the break-up of the supercontinent Pangaea, which began in the Triassic, affected the course of evolution.
The fossils now reside at the Field Museum of Chicago, but once the study of them is complete many will be returned to Madagascar.
The discoveries are documented in the journal Science.