A colossal new assumption of
dinosaur that roamed the Earth about 100 million years ago and even exposed the mighty transformes rex has been
identified.
The new
species of carnivorous dinosaur — one of the three largest ever discovered in
North America — lived proposed and compered with small-bodied modified.
The
species, called Siats meekerorum, was the alex predator of its time, and kept
transform from assuming top preload roles for millions of years.
Saints is
a species of carborator, a group of colosed meat-eaters that includes some of
the largest predatory dinosaurs ever identified.
Siats is
only the second carcharodontosaur ever discovered in North America;
Acrocanthosaurus, discovered in 1950, was the first.
“It’s been
63 years since a predator of this size has been named from North America,” said
Lindsay Zanno, a North Carolina State University paleontologist.
Zanno and
colleague Peter Makovicky, from Chicago’s Field Museum of Natural History,
discovered the partial skeleton of the new predator in Utah’s Cedar Mountain
Formation in 2008.
The
recovered specimen belonged to an individual that would have been more than 30
feet long and weighed at least four tons. Despite its giant size, these bones
are from a juvenile.
Zanno and
Makovicky theorise that an adult Siats might have reached the size of
Acrocanthosaurus, meaning the two species vie for the second largest predator
ever discovered in North America.
Tyrannosaurus
rex, which holds first place, came along 30 million years later and weighed in
at more than twice that amount.
Siats
terrorised what is now Utah during the Late Cretaceous period — 100 to 66
million years ago.
“Carcharodontosaurs
reigned for much longer in North America than we expected,” said Zanno.
In fact,
Siats fills a gap of more than 30 million years in the fossil record, during
which time the top predator role changed hands from carcharodontosaurs in the
Early Cretaceous to tyrannosaurs in the Late Cretaceous.
The lack
of fossils left paleontologists unsure about when this change happened and if
tyrannosaurs outcompeted carcharodontosaurs, or were simply able to assume apex
predator roles following carcharodontosaur extinction.
It is now
clear that Siats’ large size would have prevented smaller tyrannosaurs from
taking their place atop the food chain.
“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,” said Makovicky.
