Meet Siats the super-predator
ANEW species of predatory dinosaur that was so big it would have terrorised early tyrannosaurs has been discovered.
Siats meekerorum, named after a mythical man-eating monster, is thought to have grown up to 12m long, making it one of the three biggest meat-eating dinosaurs to have lived.
The dinosaur lived about 98 million years ago and, as the top predator of its time, would have dominated relatives of the Tyrannosaurus rex for millions of years.
The discovery suggests that tyrannosaurs were far from being the most fearsome predator in the food chain for much of their history.
However, T rex itself, which appeared about 30 million years later, would still have dwarfed the new species and probably weighed twice as much.
Dr Lindsay Zanno, a palaeontologist at North Carolina State University and the North Carolina Museum of Natural Sciences in the US, who led the study of the fossils, said: “Contemporary tyrannosaurs would have been no more than a nuisance to Siats, like jackals at a lion kill.
“It wasn’t until carcharodontosaurs like this bowed out that the stage could be set for the evolution of T rex .”
The researchers who made the discovery have described Siats as a type of carcharodontosaur — a group of large meat-eating dinosaurs that lived up to 100 million years ago and had enormous jaws filled with serrated teeth up to 20cm long.
Fossilised remains of Siats were discovered during an excavation in the Cedar Mountain Formation in Utah.
Among the fossilised bones recovered were vertebrae, a hind leg bone and part of the creature’s pelvis.
Zanno and her colleagues, whose study is published in the journal Nature Communications, believe they belonged to a juvenile that would have been more than 9m long and weighed at least four tons. They believe that adults could have grown up to 12m long. They named it Siats— pronounced see-atch — after the cannibalistic clown-like monster that appear in legends of the Ute American Indian tribe.
The meekerorum part of the creature’s name is after a family with the surname Meeker who have sponsored some of the work by the researchers in the past.
The scientists say Siats and earlier carcharodontosaurs such as Acrocanthosaurus would have dominated as the top predators for much of the Cretaceous period.
Siats would probably have preferred slow-moving herbivores as prey, but it may have fought tyrannosaurs off its kills in the same way lions will with jackals.
It was not until the final 20 million years of the age of the dinosaurs that these were then eclipsed by the tyrannosaurs.
“Carcharodontosaurs reigned for much longer in North America than we expected,” said Zanno.
“It has been 63 years since a predator of this size has been named from North America.
“You can’t imagine how thrilled we were to see the bones of this behemoth poking out of the hillside.”
Her colleague Peter Makovicky, from Chicago’s Field Museum of Natural History, said Siats would have been far larger than any other predators at the time.
“The huge size difference certainly suggests that tyrannosaurs were held in check by carcharodontosaurs, and only evolved into enormous apex predators after the carcharodontosaurs disappeared.”— © The Daily Telegraph, London