Fossils could solve mystery of extinction

A fossilised baby dinosaur found previously in Italy

Scientists say three fossilised reptile skulls could help them solve the puzzle of why half the world's land animals disappeared before the arrival of the dinosaurs.

Few fossils exist of the later Triassic and early Jurassic periods 200 million years ago.

Scientists were able to build a full-size scientific model

The Columbia University palaeontologist who found the remains with two amateurs said the reptiles were of the hypsognathus genus and similar to a groundhog.

A fourth skull found near to the site in eastern Pennsylvania in the US is yet to be identified.

Paul Olsen said: "We were looking at rocks at a construction site and there was so much new clean rock exposed after a rain, I thought there might be a lot more bones there than we had originally thought.

"And, lo and behold, once I really paid attention, there were."

Mr Olsen presented his findings to a dinosaur symposium sponsored by Philadelphia's Academy of Natural Sciences on Saturday.

The skulls were uncovered in the Newark rift basin, a geological formation created 190 million to 230 million years ago as North America pulled away from the ancient supercontinent known to scientists as Pangea.

As this occurred, so did the extinction of many of the animal species on the Earth at the time.

There was a massive increase in the size of animals as the Triassic period evolved into the Jurassic Period but scientists remain at a loss to explain what caused these events to take place.

By studying the skulls found by Mr Olsen they hope to learn more about the creatures that walked the Earth more than 200 million years ago and what could have caused them to die.