Nevertheless, the new dino would have been an intimidating creature, especially when it was part of a group. Researchers found hundreds of Mapusaurus bones dating to 100 million years ago together in a pack that would have included 18-foot-long juveniles and the over 40-foot-long adults.
"This is arguably the nastiest thing ever found, as it is the first pack found for giant meat-eating dinosaurs," said "Dino" Don Lessem, who participated in the Patagonian dig and helped to fund it.
Lessem, a dinosaur expert who served as a consultant on the film "Jurassic Park," told Animal Planet News that Mapusaurus would have been contemporaneous to the largest animal that ever lived, Argentinosaurus, which was a 125-feet-long, plant-eating dino.
"In a pack, (Mapusaurus) could take down this herbivore despite its weight — 10 times (more than) even this largest of meat eaters," he said.
Philip Currie, who also worked on the excavation and is a professor of biological sciences at the University of Alberta, told Animal Planet News that the new dino somewhat resembled
Tyrannosaurus rex.
"Mapusaurus looked something like
T. rex but had a longer, narrower skull," Currie explained. "Its teeth were shorter and more blade-like. The teeth and long skull were better adapted to biting big chunks of meat out of sauropod dinosaurs.
T. rex, on the other hand, had longer, thicker teeth for biting through the bones of its prey."
The paleontologists therefore think the newly discovered carnivore both scavenged and hunted for meat.
Rodolfo Coria, who also worked on the excavation and is a paleontologist at the Carmen Funes Museum in Argentina, told Animal Planet News that Mapusaurus may have been unique among carnivores in that it seemed to live a more social life, since it was found in a pack.
T. rex and virtually all other carnivorous dinos usually are solitary specimens, suggesting they mostly lived and hunted alone.
Coria said it is possible the big meat eaters evolved different habits for each species, and Mapusaurus simply may have been more social. The pack even appears to have passed away together in a mass die-off.
Michael Ryan, curator and head of vertebrate paleontology at the Cleveland Museum of Natural History, recently examined the dinosaur bones on a recent trip to Patagonia. He agrees with the other paleontologists.
"This new discovery helps us better understand the diversity of giant carnivorous dinosaurs," said Ryan. "Even more interesting is the fact that the find contains the remains of multiple individuals of different sizes and ages."
