Torvosaurus

*Torvosaurus tanneri*

* Timothy Bradley Artwork
* Robert F Walters Artwork

***Torvosaurus*** (Greek, “savage lizard”) was a large Megalosaurid theropod from the late Jurassic Lourinhã and Morrison Formations of 145 million years ago. It was one of the largest known Jurassic theropods, along with *Saurophaganax*, *Yangchuanosaurus*, *Megalosaurus,* and a few others. It is estimated to grew between 9 to 11 meters (27 to 36 feet) long, weighed between 2.5 and 5 tonnes, and it was one of the largest carnivores to inhabit the Earth until the Late Jurassic. It's also the widest-ranging known theropod genus.

In Portugal, it may have been the top predator. In Africa and North America there were some theropods that could challenge and present interspecies conflict; such as *Allosaurus* and *Veterupristisaurus.*

## Discovery

Fossilized remains of *Torvosaurus* have been found in North America and Portugal. In 1971, Vivian Jones, of Delta, Colorado, in the Calico Gulch Quarry in Moffat County, discovered a single gigantic thumb claw of a theropod. This was shown to James Alvin Jensen, a collector working for the Brigham Young University. In an effort to discover comparable fossils, Vivian's husband Daniel Eddie Jones directed Jensen to the Dry Mesa Quarry, where abundant gigantic theropod bones, together with *Supersaurus* remains, proved present in rocks of the Morrison Formation. From 1972 onwards the site was excavated by Jensen and Kenneth Stadtman. The genus and the type species *T. tanneri* were named and described in 1979 by Peter Malcolm Galton and Jensen.[3] In 1985 Jensen could report a considerable amount of additional material, among it the first skull elements.[4] The fossils from Colorado were further described by Brooks Britt in 1991.

The holotype BYU 2002 originally consisted of upper arm bones (humeri) and lower arm bones (radii and ulnae). The paratypes included some back bones, hip bones, and hand bones.[3] When the material described in 1985 is added, the main missing elements are the shoulder girdle and the thighbone.[5] The original thumb claw, specimen BYUVP 2020, was only provisionally referred as it had been found in a site 195 kilometres away from the Dry Mesa Quarry.[3] The holotype and paratypes represented at least three individuals: two adults and a juvenile.[5] In 1991 Britt concluded that there was no proof that the front limbs of the holotype were associated and chose the left humerus as the lectotype.[5] Several single bones and teeth found in other American sites have been referred to Torvosaurus.[5]

In 1992, fossils of a large theropod found at Como Bluff in Wyoming, were named by Robert T. Bakker e.a. as the species *Edmarka rex*.[6] This is often considered a junior synonym of *Torvosaurus*.[7] The same site has rendered comparable remains for which the nomen nudum *Brontoraptor* has been used.[8]

In 2000, material from Portugal was referred to a *Torvosaurus sp*. by Octávio Mateus and Miguel Telles Antunes.[9] In 2006 fossils from the Portuguese Lourinhã Formation were referred to *Torvosaurus tanneri*.[10] In 2012 however, Matthew Carrano e.a. concluded that this material could not be more precisely determined than a *Torvosaurus sp*.[7] In 2013 eggs and embryos were reported from Portugal, referred to *Torvosaurus*.[11] The species from Portugal was named *T. gurneyi* in honour of James Gurney in 2014. It is the largest theropod known from Europe.

## Description

Torvosaurus was a very large predator, with an estimated maximum body length of 11 m and mass of 3–5 tonnes for both T. tanneri and T. gurneyi, making Torvosaurus among the largest land carnivores of the Jurassic. Claims have been made indicating even larger sizes (A french megalosaur premaxilla). The synonymous Edmarka rex was named thus because it was assumed to rival Tyrannosaurus rex in length. Likewise "Brontoraptor" was supposed to be a torvosaur of gigantic size. The T. gurneyi specimens from Portugal initially prompted larger size estimates to be made.

In 2006 a lower end of a thighbone, specimen ML 632, was referred to Torvosaurus sp. and later to T. gurneyi. This specimen was initially stated to indicate a length of 10 m. Applying the extrapolation method of J.F. Anderson, correlating mammal weights to their femur circumference, resulted in a weight of 1930 kilogrammes. However, revised estimates performed in 2014 suggested a slightly smaller total body size for this specimen, of about 10 m (33 ft).[1] Among the differentiating features between T. gurneyi and T. tanneri are the number of teeth and size and shape of mouth. While the upper jaw of T. tanneri has more than 11 teeth, that of T. gurneyi has less.

## Material

The fossil material refered to ***Torvosaurus*** includes partial post cranial remains and elements of the skull and the maxilla.‭

In 2013, a nest with fossilized embrious was found in Portugal. Paleontologists assigned them to ***Torvosaurus gurneyi***. These are the oldest theropod eggs ever found in the world.

Fossilized remains of Torvosaurus have been found in North America, Portugal, Germany, and possibly also England, Tanzania, and Uruguay. The first discovered remains referable to Torvosaurus were discovered in 1899 by Elmer Riggs in the "Freeze-out Hills" of southeastern Wyoming. The specimen was assigned to Torvosaurus tanneri after being redescribed in 2014. More remains of a large theropod that is now believed to have been *Torvosaurus* were discovered in the Tendaguru Formation of Tanzania.

## Torvosaurus gurneyi

In 2000, fossils of some theropod were discovered in Portugal. Octávio Mateus and Miguel Antunes assigned these fossils as of ***Torvosaurus sp***. In 2006, the fossils were assigned to the type species, ***Torvosaurus tanneri***. Finally, in 2014, Mateus and ‬Hendrickx recognized the Portuguese ***Torvosaurus*** as being a of a new species, different from the type species, nowadays only known from North America. ‬The Portuguese **Torvosaurus** is now credited as belonging to ***Torvosaurus gurneyi***,‭ ‬a species named in honour of James Gurney,‭ ‬who is best known for his work creating the "Dinotopia" series of illustrated books.

One could find odd the discovery of the same genus of dinosaur in what are now two separate continents. However, during the late Jurassic, the Atlantic Ocean was just starting to form and, consequently, animals (and, of course, dinosaurs) could walk between the continents, at certain times. In fact, Torvosaurus isn´t the only genus of dinosaur to be found in both continents: **Allosaurus**, ***Ceratosaurus*** and ***Stegosaurus*** are also found in Portugal. This is why researchers consider the Lourinhã Formation to be analogous to the more famous Morrison Formation.

## Paleobiology

*Torvosaurus* was a huge theropod for its time, and probably fed on large Sauropods like *Diplodocus* and *Dinheirosaurus* (now a species of ***Supersaurus***) and stegosaurs like *Stegosaurus* and *Miragaia*. It probably also preyed on the smaller carnivores from time to time as well. It had long, muscular legs and mid-sized arms, good for gripping and holding onto prey. It also had a long, narrow skull, probably used to go in and repeatedly bite at larger herbivores. The largest specimens of Torvosaurus tanneri could reach 11 m in length. The specimen found in Portugal was of an individual that exceded 10 meters in length. Unlike most other large theropods, ***Torvosaurus*** seemed to have thicker teeth, where others have thin, blade-like teeth, which may suggest it had a stronger bite force than most other theropods its size.

## JPInstitute.com Description

Torvosaurus was one of the largest, most ferocious meat-eating dinosaurs ever to walk the Earth. Its fossil bones show that it was not only big, but that it was also very strong. It appeared right after Allosaurus became extinct and would have been the top predator of its time.

Torvosaurus has had several different classifications within the theropod family. It is often compared to Allosaurus, but it was much bigger and appears to have been more closely related to the European megalosaurs. Similarities between Torvosaurus and Ceratosaurus have also been noted in studies of the fossils.

## Dinosaur Field Guide Description

Torvosaurus ("'savage lizard") is a large meat-eating dinosaur. Its bones are very thick and sturdy, its arms are short but massive, and its thumb claws are huge. It lived in the same environment with several other giant meat-eaters (including Allosaurus and Ceratosaurus), but Torvosaurus was the "bruiser" of the bunch. While Allosaurus used its speed and agility to hunt, and Ceratosaurus used its oversized teeth, Torvosaurus seems to have relied on its brute strength, Torvosaurus was first found by legendary fossil hunter "Dinosaur" Jim Jensen in the Morrison Formation of Colorado. This formation contains many kinds of plant-eating dinosaurs but is especially known for sauropods, or giant long-necks, like Apatosaurus, Brachiosaurus, and Camarasaurus, and stegosaurs like Stegosaurus. Torvosaurus might have been well suited for attacking young sauropods. It was probably not very fast, but neither were they.

### Fun Facts

The strong arms of Torvosaurus are peculiar: The forearms are less than half the length of the upper arm!

### Trivia

"Dinosaur" Jim Jensen found a giant specimen of Brachiosaurus (which he called "Ultrasaurus") and a giant specimen of Diplodocus (which he called "Supersaurus") in the same quarry in which he discovered Torvosaurus.

## Links

http://web.archive.org/web/20040214172738fw\_/http://www.jpinstitute.com/dinopedia/dinocards/dc\_torvo.html#

## References

* http://ageofdinosaurs.com/dinosaurs/torvosaurus.htm
* http://www.dinochecker.com/dinosaurs/TORVOSAURUS
* Dinosaur Revolution
* https://dinosaursandbarbarians.com/2015/08/08/torvosaurus-the-grizzly-bear-of-the-jurassic/
* https://www.tandfonline.com/doi/abs/10.1080/08912963.2013.807254
* https://peerj.com/articles/4963/
* https://link.springer.com/article/10.1007%2Fs41513-017-0003-9
* https://www.researchgate.net/publication/260561984\_Torvosaurus\_gurneyi\_n\_sp\_the\_Largest\_Terrestrial\_Predator\_from\_Europe\_and\_a\_Proposed\_Terminology\_of\_the\_Maxilla\_Anatomy\_in\_Nonavian\_Theropods
* https://www.researchgate.net/publication/315862828\_New\_data\_on\_the\_anatomy\_of\_Torvosaurus\_and\_other\_remains\_of\_megalosauroid\_Dinosauria\_Theropoda\_from\_the\_Upper\_Jurassic\_of\_Portugal
* https://www.reuters.com/article/us-science-dinosaur-idINBREA242G620140305
* https://www.sciencedirect.com/science/article/abs/pii/S089598111930505X
* https://www.researchgate.net/publication/326210538\_The\_largest\_European\_theropod\_dinosaurs\_Remains\_of\_a\_gigantic\_megalosaurid\_and\_giant\_theropod\_tracks\_from\_the\_Kimmeridgian\_of\_Asturias\_Spain
* https://www.deviantart.com/randomdinos/art/Torvosaurus-tanneri-skeletal-reconstruction-874967279
* https://docs.google.com/spreadsheets/d/10kENNmyqPts-fv-nCgK4Rse5YggniHiVTvj6BVv1JDo/edit#gid=929633367
* https://academic.oup.com/california-scholarship-online/book/28516/chapter-abstract/237302873?redirectedFrom=fulltext