Torvosaurus
Encyclopedia
Torvosaurus is a genus
of large theropod dinosaur
that lived during the Late Jurassic
period (mid-late Kimmeridgian
stage in North America, early Tithonian
stage in Europe). The name Torvosaurus means "savage lizard" and is derived from the Latin
torvus ("savage") and the Greek
σαυρος/sauros ("lizard").
Fossilized remains of Torvosaurus have been found in North America
and Portugal
. Torvosaurus reached 9 to 11 meters
(30 to 36 ft) in length and an estimated weight of about 2 metric tons (2.2 tons
), which made it the largest carnivore
of its time, except for Epanterias
(which may have been just a big Allosaurus
) and Saurophaganax
.
It was first discovered by James A. Jensen
and Kenneth Stadtman in the rocks of the Morrison Formation
at the Dry Mesa Quarry
, Colorado
in 1972. The genus and the type species
T. tanneri were named and described in 1979 by Peter M. Galton
and Jensen. The type specimen from Colorado was further described by Brooks Britt, and the Portuguese specimen by O. Mateus and M.T. Antunes.
The holotype
is represented by an upper arm bone (humerus
) and lower arm bones (radius
and ulna
). Additional material includes some skull bones, back bones, hip bones and 'hand' bones.
but is seemingly more advanced. Its classification is still uncertain but its family Megalosaurid
ae is most commonly held as a basal
branch of Tetanurae
, less derived than carnosaurs or coelurosaurs, and likely related to the spinosaurids.
indicates even larger animals. In 2006 a nearly complete maxilla found in Portugal was assigned to Torvosaurus tanneri. It measured 63 cm in length (2.13 ft), significantly larger than the 47 cm (1.54 ft) long maxilla of the American specimen (total skull length 118 cm [3.87 ft]). Based on this, a skull length of 158 cm (5.18 ft) was estimated for the Portuguese specimen. This is comparable to the largest T. rex skulls, and makes Torvosaurus the largest known Jurassic theropod (surpassing Saurophaganax
/Allosaurus
maximus and Edmarka
), and among the largest of all theropods. A partial femur from another individual belongs to an animal estimated as 11 m (36 ft) long.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of large theropod dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
that lived during the Late Jurassic
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 161.2 ± 4.0 to 145.5 ± 4.0 million years ago , which is preserved in Upper Jurassic strata. In European lithostratigraphy, the name "Malm" indicates rocks of Late Jurassic age...
period (mid-late Kimmeridgian
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age or stage in the Late or Upper Jurassic epoch or series. It spans the time between 155.7 ± 4 Ma and 150.8 ± 4 Ma . The Kimmeridgian follows the Oxfordian and precedes the Tithonian....
stage in North America, early Tithonian
Tithonian
In the geologic timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic series. It spans the time between 150.8 ± 4 Ma and 145.5 ± 4 Ma...
stage in Europe). The name Torvosaurus means "savage lizard" and is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
torvus ("savage") and the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...
σαυρος/sauros ("lizard").
Fossilized remains of Torvosaurus have been found in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Portugal
Portugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
. Torvosaurus reached 9 to 11 meters
Metre
The metre , symbol m, is the base unit of length in the International System of Units . Originally intended to be one ten-millionth of the distance from the Earth's equator to the North Pole , its definition has been periodically refined to reflect growing knowledge of metrology...
(30 to 36 ft) in length and an estimated weight of about 2 metric tons (2.2 tons
Short ton
The short ton is a unit of mass equal to . In the United States it is often called simply ton without distinguishing it from the metric ton or the long ton ; rather, the other two are specifically noted. There are, however, some U.S...
), which made it the largest carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
of its time, except for Epanterias
Epanterias
Epanterias is a dubious genus of theropod dinosaur from the Kimmeridgian-Tithonian-age Upper Jurassic upper Morrison Formation of Garden Park, Colorado. It was described by Edward Drinker Cope in 1878. The type species is Epanterias amplexus. This genus is based on what is now AMNH 5767, parts of...
(which may have been just a big Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
) and Saurophaganax
Saurophaganax
Saurophaganax is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma . Some paleontologists consider it to be a species of Allosaurus...
.
It was first discovered by James A. Jensen
James A. Jensen
James A. Jensen , was an American paleontologist. His extensive collecting program at BYU in the Utah-Colorado region which spanned 23 years was comparable in terms of the number of specimens collected to that of Barnum Brown during the early 20th century. He was given the name "Dinosaur Jim"...
and Kenneth Stadtman in the rocks of the Morrison Formation
Morrison Formation
The Morrison Formation is a distinctive sequence of Late Jurassic sedimentary rock that is found in the western United States, which has been the most fertile source of dinosaur fossils in North America. It is composed of mudstone, sandstone, siltstone and limestone and is light grey, greenish...
at the Dry Mesa Quarry
Dry Mesa Quarry
The Dry Mesa Dinosaur Quarry is situated in southwestern Colorado, USA, near the town of Delta. Its geology forms a part of the Morrison Formation and has famously yielded a great diversity of animal remains from the Jurassic Period, among them Ceratosaurus, Supersaurus, and Torvosaurus...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
in 1972. The genus and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
T. tanneri were named and described in 1979 by Peter M. Galton
Peter Galton
Peter M. Galton is a British vertebrate paleontologist working in America, who has to date written or co-written about a hundred papers in scientific journals or chapters in paleontology textbooks, especially on ornithischian and prosauropod dinosaurs.With Robert Bakker in a joint article...
and Jensen. The type specimen from Colorado was further described by Brooks Britt, and the Portuguese specimen by O. Mateus and M.T. Antunes.
Material
Holotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
is represented by an upper arm bone (humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
) and lower arm bones (radius
Radius (bone)
The radius is one of the two large bones of the forearm, the other being the ulna. It extends from the lateral side of the elbow to the thumb side of the wrist and runs parallel to the ulna, which exceeds it in length and size. It is a long bone, prism-shaped and slightly curved longitudinally...
and ulna
Ulna
The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form and runs parallel to the radius, which is shorter and smaller. In anatomical position The ulna is one of the two long bones in the forearm, the other being the radius. It is prismatic in form...
). Additional material includes some skull bones, back bones, hip bones and 'hand' bones.
Systematics
Torvosaurus is related to the earlier MegalosaurusMegalosaurus
Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
but is seemingly more advanced. Its classification is still uncertain but its family Megalosaurid
Megalosaurid
Megalosauridae was a family of relatively primitive tetanuran theropod dinosaurs, order Saurischia. They were small-to-large carnivores with sharp teeth and three claws on each hand. Some members of this group were Megalosaurus, Eustreptospondylus, Streptospondylus and Torvosaurus...
ae is most commonly held as a basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
branch of Tetanurae
Tetanurae
Tetanurae, or "stiff tails", is a clade that includes most theropod dinosaurs, as well as birds. Tetanurans first appear during the early or middle Jurassic Period.-Definition:...
, less derived than carnosaurs or coelurosaurs, and likely related to the spinosaurids.
Largest theropod of the Jurassic
The size of Torvosaurus is not definitely known because only incomplete material has been found, but it was a large theropod. North American Torvosaurus material is estimated as belonging to an individual about 9.0 meters long (29 ft), with a weight of about 1.95 metric tons (2.15 tons). Material from PortugalPortugal
Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...
indicates even larger animals. In 2006 a nearly complete maxilla found in Portugal was assigned to Torvosaurus tanneri. It measured 63 cm in length (2.13 ft), significantly larger than the 47 cm (1.54 ft) long maxilla of the American specimen (total skull length 118 cm [3.87 ft]). Based on this, a skull length of 158 cm (5.18 ft) was estimated for the Portuguese specimen. This is comparable to the largest T. rex skulls, and makes Torvosaurus the largest known Jurassic theropod (surpassing Saurophaganax
Saurophaganax
Saurophaganax is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma . Some paleontologists consider it to be a species of Allosaurus...
/Allosaurus
Allosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
maximus and Edmarka
Edmarka
Edmarka is a genus of dinosaur from the Late Jurassic of North America. The name honors scientist Bill Edmark. It was a theropod closely related to Torvosaurus, and may, in fact, be a junior synonym of that genus. Its fossils, including a partial skeleton, were found at Como Bluff, Wyoming.The...
), and among the largest of all theropods. A partial femur from another individual belongs to an animal estimated as 11 m (36 ft) long.