STL Science Center

STL Science Center

20 July 2013

Key Features of Torvosaurus

The natural conclusion to yesterday's art by Davide Bonadonna
Torvosaurus differs from many other North American and European giants in a number of ways. Obviously the European material from Portugal did not undergo the adaptations witnessed in other European dinosaurs that are the results of insular dwarfism (as so recently discussed both last week and in the discussion of Balar bondoc). In North America the material gathered in Colorado and elsewhere, including potential material from Wyoming and Utah, was slightly smaller than or equal to the largest predators found in the west as contemporaries of Torvosaurus; "savage lizard" sounds a little more fearsome than "different lizard" (Allosaurus) but a little less fearsome than "lizard-eating master" (Saurophaganax) and so is nestled in both size and fantastic nature of name nicely in the middle of its contemporaries. Physically there were also many differences between this megalosaurid and its allosaurid contemporaries preserved in the fossil remains; no good "mummifications" exist for all of these contemporaries to my knowledge that would allow for extensive soft anatomy comparison.

Skeleton at the North American Museum of Ancient Life (Thanksgiving Point, Lehi, UT), photo courtesy of user Ninjatacoshell
The teeth of Torvosaurus are impressive, though not completely definitive of the genus or the family. Some of the skeletal markers that make it different from its contemporaries include the length of its ilia and pubic bones as well as lack of ornamentations on specific areas of the skull such as the lacrimal ridges (a bone of the "face" near the antorbital fenestra and nasal bones). Allosaurus, especially in the past few years, has been depicted with rather prominent nasal, orbital, and lacrimal ridges of bone and soft tissue, particularly the latter. Megalosaurids, such as Torvosaurus, show no evidence of ornamentation along these bones and it is assumed that the lack of ornamentation in the bone was a precursor for a lack of ornamentation of soft tissue in those areas. The skulls of the two dinosaurs are also different in overall size and length with Torvosaurus possessing a longer nasal bone that creates more solid bone area between the nares and antorbital fenstra than is found in the more rounded off and shortened muzzle of Allosaurus. Fore and hindlimbs of Torvosaurus are somewhat like those of Allosaurus; both have three clawed hands as well as feet. The claws of Torvosaurus appear slightly larger and stronger, but I have not seen a documented study to support this at the current time.

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