Jurassic Morrison Torvosaurus Tooth VF-JC-24-017

Torvosaurus sp.

Morrison Formation

Upper Jurassic

Moffat County, Colorado

Seen here is a good example of the rare Morrison Formation tooth of Torvosarus. The tooth is 5 cm long and is 3.5 cm wide at the base.  It has some excellent serrations on the mesial carina but there are only a few serrations preserved on the distal carina due to the partially crushed preservation.  There are 1.5 serrations per millimeter which is characteristic of an adult of the genus Torvosaurus.  During burial and fossilization this specimen developed natural fractures and some minor dislocation.  The tip is complete and unrestored. A small portion of a ware facet is seen at the tip on the lingual side.  The natural fractures have been stabilized and partially filled.  Yet this is still a remarkable specimen considering the rarity.

Torvosaurus is a genus of carnivorous megalosaurid theropod dinosaurs that lived approximately 153 to 148 million years ago during the later part of the Jurassic Period in what is now Colorado and Portugal. It contains two currently recognized species, Torvosaurus tanneri and Torvosaurus gurneyi.

In 1979 the type species Torvosaurus tanneri was named: it was a large, heavily built, bipedal carnivore, that could grow to a length of about 10 m (33 ft). T. tanneri was among the largest carnivores of its time, together with Epanterias and Saurophaganax (which could be both synonyms of Allosaurus). Specimens referred to Torvosaurus gurneyi were initially claimed to be up to eleven metres long but later shown to be smaller.  Based on bone morphology Torvosaurus is thought to have had short but very powerful arms.

Torvosaurus was a very large predator, with an estimated maximum body length of 10 meters (33 ft) and mass of 3.6–4.5 tonnes (4–5 short tons) for both T. tanneri and T. gurneyi, making Torvosaurus among the largest carnivores of the Jurassic. Claims have been made indicating even larger sizes. The synonymous Edmarka rex was named thus because it was assumed to rival Tyrannosaurus rex in length and weight. Likewise, "Brontoraptor" was supposed to be a torvosaur of gigantic size.  Torvosaurus had an elongated, narrow snout, with a kink in its profile just above the large nostrils. The frontmost snout bone, the premaxilla, bore three rather flat teeth oriented somewhat outwards with the front edge of the teeth crown overlapping the outer side of the rear edge of the preceding crown. The maxilla was tall and bore at least eleven rather long teeth. The antorbital fenestra was relatively short. The lacrimal bone had a distinctive lacrimal horn on top; its lower end was broad inside view. The eye socket was tall with a pointed lower end. The jugal was long and transversely thin. The lower front side of the quadrate bone was hollowed out by a tear-shaped depression, the contact surface with the quadratojugal. Both the neck vertebrae and the front dorsal vertebrae had relatively flexible ball-in-socket joints. The balls, on the front side of the vertebral centra, had a wide rim. The tail base was stiffened in the vertical plane by high and inside view wide neural spines. The upper arm was robust, the lower arm robust but short. Whether the thumb claw was especially enlarged, is uncertain. In the pelvis, the ilium resembled that of Megalosaurus and had a tall, short, front blade and a longer pointed rear blade. The pelvis as a whole was massively built, with the bone skirts between the pubic bones and the ischia contacting each other and forming a vaulted closed underside.