A team of paleontologists and volunteers has discovered remains of at least seven different killer dinosaurs that once lived in what is now south-eastern Australia.

A study, published in the journal PLoS ONE, describes the finds of scientists and volunteers from Monash University and Museum Victoria who uncovered a higher than expected biodiversity of meat-eating theropod dinosaur fossils from between 105 and 120 million years ago.

“We had not expected to find fossils from such a large range of dinosaur species in this area,” said study co-author Dr Tom Rich. “The fossils we have collected range from tiny, cat-sized killers to Australia’s version of T. Rex, a 9-meter-long predator with powerful arms and razor-sharp claws.”

The team identified up to seven theropod dinosaurs, belonging to the Ceratosauria, Spinosauridae, Tyrannosauroidea, Maniraptora, a basal coelurosaur, and possibly Ornithomimosauria, and Allosauroidea.

“In total 1500 isolated bones and teeth of various kinds of dinosaurs have been found in Victoria, Australia so far. Their meaning is only beginning to be unraveled by detailed study and comparisons with other fossils worldwide,” Dr Rich added.

At the time these dinosaurs ruled, southern Australia was part of the Antarctic Circle. Despite the cold, there was a high diversity of small predators, similar to the Velociraptor, featured in ‘Jurassic Park’.

“One of the reasons for the success of small, theropod dinosaurs may be their warm-blood. As close relatives of birds, they had feathery insulation which helped maintain high body temperatures,” Dr Rich explained.

“The cool, damp climate may also explain the discovery of the same dinosaur species in both Australia and the northern continents.”

Research leader Dr Roger Benson from the University of Cambridge said: “the study reports new discoveries and rationalizes previous investigations.”