Torvosaurus
Name:
Torvosaurus
(Savage lizard).
Phonetic: Tor-voe-sore-us.
Named By: Peter Galton & James A.
Jensen - 1979.
Synonyms: Edmarka.
Classification: Chordata, Reptilia, Dinosauria,
Theropoda, Megalosauridae Megalosaurinae.
Species: T. tanneri (type),
T. gurneyi.
Diet: Carnivore.
Size: Usually estimated between 9 and 10
meters long, but sometimes credited to be as much as 11 meters long.
Known locations: USA - Colorado - Morrison
Formation. Portugal - Lourinh� Formation.
Time period: Kimmeridgian to Tithonian of the
Jurassic.
Fossil representation: Partial post cranial remains
and elements of the skull including the maxilla. Further remains are
thought to possibly be attributable to the genus.
One
of the biggest fields of study regarding Torvosaurus
is its supposed
size and possible claim to being the largest known Jurassic era
theropod dinosaur. Though known from only partial remains, fossils
from the Morrison Formation have been compared to other better
preserved theropod genera of the time to yield estimates of around nine
meters long. However further fossil material, namely a maxilla
(upper jaw bone) has been found to be larger than equivalent remains
in North America, and when the North American remains are scaled up
for comparison a new estimate of up to eleven meters long come to
light. If eleven meters is correct then Torvosaurus
would certainly
be one of the largest predators in North America during the Jurassic,
and be even larger than the smaller estimate for Saurophaganax
(a
theropod estimated between ten and thirteen meters long).
Because
of its potential large size, Torvosaurus has been
speculated by some
to have been a scavenger that used its larger size to intimidate and
scare off smaller theropods such as Marshosaurus,
Ceratosaurus
and
even Allosaurus
from their kills. However this large size would have
given Torvosaurus an advantage in dealing with
larger prey types that
would have been too slow to run away even from a theropod the size of
Torvosaurus. Potential prey for Torvosaurus
could have included
ornithopods like Camptosaurus
and plated dinosaurs like Stegosaurus.
Sauropods
such as Diplodocus,
Apatosaurus,
Brachiosaurus
and
Camarasaurus
are also known to have been quite numerous, and smaller
juveniles of these genera in particular would have been vulnerable to
predators such as Torvosaurus.
Another
large theropod called Edmarka
is known to have stalked North America
during the Jurassic, though there is speculation that Edmarka
might
actually be the same dinosaur as Torvosaurus, an
idea that has increased in popularity in recent years.
Torvosaurus gurneyi
Back
in the year 2000, new theropod material was recovered from
Portugal, and in a subsequent description Oct�vio Mateus and Miguel
Telles Antunes assigned these fossils as Torvosaurus
sp. Later in
2006, the fossils from the Lourinh� Formation were assigned to the
Torvosaurus type species T. tanneri.
By 2012 another study by
Carrano et al went to the point that the Torvosaurus
fossils could be
defined further than just a generic species, and in 2013 eggs
with fossilised embryos inside them were assigned to Torvosaurus.
Finally in 2014 description by Hendrickx and Mateus the Portuguese
fossils were recognised as a species entirely separate from the type
species which today is only known from North America. The Portuguese
Torvosaurus are 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.
It
might seem strange that two species of the same dinosaur could co-exist
upon what are now separate continents, but it is important to
remember that in the late Jurassic North America and Europe were closer
and still connected and that land animals could literally walk between
the two. Torvosaurus is also not the only one
either, with species
of other dinosaur genera which are often described as North American
such as Allosaurus, Ceratosaurus
and Stegosaurus also being known
from the Portuguese Lourinh� Formation. In fact many researchers
often point out that in terms of the types of animals, the Lourinh�
Formation is analogous to the famous Morrison Formation of the United
States. Other dinosaur genera that Torvosaurus gurneyi
may have come
into contact with include the stegosaurs
Miragaia
and Dacentrurus,
the sauropods Lusotitan
and Lourinhasaurus,
the theropod
Lourinhanosaurus,
as well as ornithopods and possibly even
ankylosaurs.
Torvosaurus
gurneyi was initially described as being about eleven meters long,
but revisions to this estimate have already been made which has seen
estimates reduced to around the ten meter mark. This would still make
Torvosaurus gurneyi one of the largest theropod
dinosaurs known to have
lived in Europe, and still larger than many of the earlier European
theropods such as Megalosaurus,
Dubreuillosaurus
and Poekilopleuron
and Magnosaurus.
Torvosaurus, Ceratosaurus, Allosaurus.
Further reading
- A new large theropod dinosaur from the Upper Jurassic of Colorado.
Brigham Young University Geology Studies 26(1):1-12 - P. M. Galton
& J. A. Jenson - 1979.
- Theropods of Dry Mesa Quarry (Morrison Formation, Late Jurassic),
Colorado, with emphasis on the osteology of Torvosaurus
tanneri -
Brigham Young University Geology Studies 37: 1-72 - B. Britt - 1991.
- Edmarka rex, a new, gigantic theropod dinosaur
from the middle
Morrison Formation, Late Jurassic of the Como Bluff outcrop region -
Hunteria, 2(9): 1–24 - R. T. Bakker, J. Siegwarth, D. Kralis &
J. Filla - 1992.
- Torvosaurus sp.(Dinosauria: Theropoda) in the
late Jurassic of
Portugal. - In I Congresso Ib�rico de Paleontologia/XVI Jornadas de la
Sociedad Espa�ola de Paleontolog�a (pp. 115-117) - O. Mateus &
M. T. Antunes - 2000.
- The large theropod fauna of the Lourinha Formation (Portugal) and its
similarity to that of the Morrison Formation, with a description of a
new species of Allosaurus - New Mexico Museum of
Natural History and
Science Bulletin, 36. - O. Mateus, A. Walen & M. T. Antunes -
2006.
- Late Jurassic Dinosaurs From The Morrison Formation (USA), The
Lourinh� amd Alcobaca Formations (Portugal), and the Tebdaguru Beds
(Tanzania): A Comparison - Octavio Mateus - In Paleontology and Geology
of the Upper Jurassic Morrison Formation. New Mexico Museum of Natural
History and Science Bulletin 36. - J. R.Foster, & S. G. R. M.
Lucas, eds. - 2006.
- The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of
Systematic Palaeontology 10 (2): 211–300. - M. T. Carrano, R. B. J.
Benson & S. D. Sampson - 2012.
- Filling the gaps of dinosaur eggshell phylogeny: Late Jurassic
Theropod clutch with embryos from Portugal. - Scientific Reports 3 :
Article number: 1924 doi:10.1038/srep01924 - Ricardo Ara�jo, Rui
Castanhinha, Rui M. S. Martins, Oct�vio Mateus, Christophe Hendrickx,
F. Beckmann, N. Schell & L. C. Alves - 2013.
- Torvosaurus gurneyi n. sp., the Largest
Terrestrial Predator from
Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian
Theropods - PLoS ONE 9 (3): e88905. - C. Hendrickx & O. V.
Mateus - 2014.
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