March 6, 2014
New Species Of Torvosaurus Was Largest European Land Predator
Lawrence LeBlond for redOrbit.com - Your Universe Online
Fossils of Torvosaurus, a large Jurassic-era theropod predator, were first unearthed in North America in 1971, later being named Torvosaurus tanneri. Examples of this dinosaur had not existed elsewhere until 2000, when paleontologists discovered another Torvosaurus fossil in Europe.
The discovery, which came from a site just north of Lisbon, Portugal, led scientists to initially assume the remains were that of T. tanneri. However, closer comparisons of the shin bone, upper jawbone, teeth and partial tail have offered up new evidence that this is in fact a new species, being named T. gurneyi.
In a paper published in the journal PLOS ONE, coauthors Christophe Hendrickx and Octavio Mateus from Universidade Nova de Lisboa (New University of Lisbon) and Museu da Lourinhã describe the dinosaur as the largest land predator ever discovered in Europe, as well as one of the largest carnivorous dinosaurs from the Jurassic.
Finding this dinosaur so far from the original discovery in the US has offered up some new evidence on existing discoveries in Portugal’s 157- to 145-million-year-old rocks. Along with Torvosaurus, paleontologists have previously dug up Allosaurus and Ceratosaurus fossils within the Lourinhã Formation, both of which have also been previously identified in North America. Despite having a wide Atlantic Ocean between them, it seems Portugal and North America share a unique connection in the dinosaurian world.
This emerging connection is what initially led paleontologists to assume what they had discovered was in fact a fragment of T. tanneri. The new identification, T. gurneyi, is in honor of Dinotopia artist James Gurney. It is distinguishable from its North American counterpart based on three anatomical characteristics, all from the mouth.
Hendrickx and Mateus note that their Torvosaurus is different in the fact that it has fewer than 11 teeth in its maxilla, relatively short and blunt interdental plates between the teeth and lacks a protuberant ridge. Together with the tail bone, these findings paint a clear picture of a new species.
Despite giving the fossil a new species name, Hendrickx and Mateus note that tooth count and interdental plates can differ between individuals and age. They maintain that the characteristics they point out as different in the new species may not provide strong enough evidence to establish it as a new species without a larger sample size to go on. They acknowledge that more complete specimens will be needed to piece together the puzzle called Torvosaurus.
Discovering more Torvosaurus specimens may be difficult, due to the fact that it has rarely turned up in Jurassic rock. Allosaurus has been much more abundant and even the rare Ceratosaurus is more known than Torvosaurus.
Still, based on the evidence in hand, the team estimates that T. gurneyi in life would have been at the top of the food chain when it roamed the landscape more than 150 million years ago. It would have reached a length of 33 feet and weighed as much as 5 tons.
"This is not the largest predatory dinosaur we know. Tyrannosaurus, Carcharodontosaurus, and Giganotosaurus from the Cretaceous were bigger animals," said Hendrickx in a statement. "With a skull of [nearly 45 inches], Torvosaurus gurneyi was however one of the largest terrestrial carnivores at this epoch, and an active predator that hunted other large dinosaurs, as evidenced by blade shape teeth up to [four inches]."
"We all know about T. rex, but Tyrannosaurus was a Cretaceous animal," Prof Mateus told Jonathan Amos of BBC News. "Our dinosaur was Jurassic. The difference in age is striking - it's 80 million years. So, when T. rex walked on Earth, Torvosaurus was already a fossil."
"Besides dinosaurs, we had turtles, crocodiles, those flying reptiles we call pterosaurs, and also small mammals," Hendrickx told BBC News. "And for the flora - it must have been quite luxuriant. A lot of conifers and gingkos. [It would have looked] something like a tropical environment."
"This was an area with a lot of rivers, a lot of fresh water; and a lot of vegetation. So, it would have been good for herbivores, and with herbivores come some carnivores like Torvosaurus," added Prof Mateus.
In explaining how North America’s and Portugal’s dinosaurs share a similar connection, the team told National Geographic that continental uplift may have created temporary land bridges between Jurassic North America and the proto-Iberian Peninsula about 163.5 million years ago.
If these corridors were around for a long enough period, it could have allowed dinosaurs such as Torvosaurus, Allosaurus and Ceratosaurus, among others, to make the trek before the sea once again reclaimed the land, stranding dinosaur population on either side.