Torvosaurus Tanner DBi

''Torvosaurus'' () is a genus of large megalosaurine theropod dinosaur that lived approximately 165 to 148 million years ago during the Callovian to Tithonian ages of the late Middle and Late Jurassic period in what is now Colorado, Portugal, Germany, and possibly England, Spain, Tanzania, and Uruguay. It contains two currently recognized species, ''Torvosaurus tanneri'' and ''Torvosaurus gurneyi'', plus a third unnamed species from Germany.

In 1979, the type species ''Torvosaurus tanneri'' was named. Measuring around long and weighing approximately , ''T. tanneri'' was among the largest terrestrial carnivores in North America during the Late Jurassic. Specimens of ''Torvosaurus gurneyi'' were measured up to in length and in body mass, suggesting that it was much larger than ''T. tanneri'' and was the largest terrestrial carnivore in Europe during the Late Jurassic. Based on bone morphology, ''Torvosaurus'' is thought to have had very powerful short arms.

Discovery

Fossilized remains of ''Torvosaurus'' have been found in North America, Portugal, Germany, and possibly in England, Spain, 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, northwest of Medicine Bow. The material consisted of part of the left foot and right hand and they were taken to the Field Museum of Natural History in Chicago, where they were stored until being re-discovered around 2010. The specimen was assigned to ''Torvosaurus tanneri'' after being described in 2014.Hanson, Michael; Makovicky, Peter J. "A new specimen of ''Torvosaurus tanneri'' originally collected by Elmer Riggs". ''Historical Biology, volume 26, issue 6 (2014).'' Pages 775-784. https://www.tandfonline.com/doi/abs/10.1080/08912963.2013.853056?scroll=top&needAccess=true&journalCode=ghbi20 .

More remains of a large theropod that is now believed to have been ''Torvosaurus'' were discovered in the Tendaguru Formation of Tanzania and was named "''Megalosaurus''" ''ingens'' by Werner Janensch in 1920, based on the specimen MB R 1050, a long tooth from German East Africa (now Tanzania). It was eventually reclassified as a probable member of Carcharodontosauridae before being reclassified as a probable member of the ''Torvosaurus'' genus in 2020. Although it was only referred to as ''Torvosaurus sp.'', one commentator has noted it could potentially be called ''Torvosaurus ingens''. Soto ''et al.'' described teeth of a member of the genus ''Torvosaurus'' from the Tacuarembó Formation of Uruguay. The authors noted that some of the specimens of “''Megalosaurus” ingens'' figured by Werner Janensch share the features of the Uruguayan material and stated that the materials from Tanzania and Uruguay may represent the same taxon, due to geographical proximity, but ultimately concluded that, based on only teeth, they do not share any derived characteristics to distinguish them from the described species of the genus, ''T. tanneri'' and ''T. gurneyi''.Tacuarembó Formation
at Fossilworks.org However, Rauhut ''et al.'' consider the teeth to be undiagnostic, being coherent in size and shape with a variety of other theropods (including carcharodontosaurids), thus considering their attribution to the genus to be problematic.

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 who was working for 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 onward, the site was excavated by Jensen and Kenneth Stadtman. The type species ''Torvosaurus tanneri'' was named and described in 1979 by Peter Malcolm Galton and Jensen. The genus name ''Torvosaurus'' derives from the Latin word ''torvus'', meaning "savage", and the Greek word ''sauros'' (σαυρος), meaning "lizard". The specific name ''tanneri'' comes from the, first counselor in the First Presidency of the Church of Jesus Christ of Latter-day Saints, Nathan Eldon Tanner.

In 1985, Jensen could report a considerable amount of additional material, among it being the first skull elements.Jensen, J.A., 1985, "Uncompahgre dinosaur fauna: A preliminary report", ''Great Basin Naturalist'', 45: 710–720 The fossils from Colorado were further described by Brooks Britt in 1991.Britt, B., 1991,
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 The holotype, BYU 2002, originally consisted of upper and lower arm bones. The paratypes included some back bones, hip bones, and hand bones. When the material described in 1985 is added, the main missing elements are the shoulder girdle and the thighbone. The original thumb claw, specimen BYUVP 2020, was only provisionally referred, as it had been found in a site away from the Dry Mesa Quarry. The holotype and paratypes represented at least three individuals, these being two adults and a juvenile. 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. Several single bones and teeth found in other American sites have been referred to ''Torvosaurus''.

In 1992, fossils of a large theropod found at Como Bluff in Wyoming contained skull, shoulder girdle, pelvic, and rib elements. They were named by Robert T. Bakker ''et al.'' as the species ''Edmarka rex''. Bakker ''et al'' were impressed with the size of ''Edmarka'', noting that it "would rival '' T. rex'' in total length," and viewing this approximate size as "a natural ceiling for dinosaurian meat-eaters." This was often considered a junior synonym of ''Torvosaurus'', but a detailed analysis has not been carried out yet. The same site has rendered comparable remains for which the ''nomen nudum'' ''Brontoraptor'' has been used.Siegwarth, J., Linbeck, R., Bakker, R. and Southwell, B. (1996). Giant carnivorous dinosaurs of the family Megalosauridae. ''Hunteria'' 3:1–77. Most researchers now regard both specimens as belonging to ''Torvosaurus tanneri''. However, ''Edmarka rex'' and ''Brontoraptor'' require reclassification to determine whether or not they actually belong to ''T. tanneri'', as all the specimens described prior to their discovery indicate that they reached their adult size and both incomplete specimens lack detailed osteological descriptions.

In 2012, a still undescribed, 55% complete specimen was discovered in Colorado in the Skull Creek Quarry, which is an exposure of the Morrison Formation. The specimen, nicknamed "Elvis", included the pelvic, spine, and hind limb bones, a complete, associated backbone, as well as cranial elements. It is the most complete specimen of ''Torvosaurus'' found to date. A mounted skeleton of the specimen, with missing parts reconstructed with casts from other ''Torvosaurus'' specimens, is currently on display in the Museum of Natural History & Science in Cincinnati.

In 2000, material from Portugal was referred to a ''Torvosaurus'' sp. by Octávio Mateus and Miguel Telles Antunes.Mateus, O., & Antunes, M. T. (2000). ''Torvosaurus'' sp.(Dinosauria: Theropoda) in the late Jurassic of Portugal. In I Congresso Ibérico de Paleontologia/XVI Jornadas de la Sociedad Española de Paleontología (pp. 115–117) In 2006, fossils from the Portuguese Lourinhã Formation were referred to ''Torvosaurus tanneri''. In 2012, however, Matthew Carrano ''et al.'' concluded that this material could not be more precisely determined than a ''Torvosaurus'' sp. In 2013 and 2014, eggs with and without embryos were reported from Portugal and referred to ''Torvosaurus''. The species from Portugal was named ''T. gurneyi'' in honor of James Gurney in 2014, the creator of the ''Dinotopia'' series of books. It is the largest named theropod known from Europe, although an isolated anterior caudal vertebra from the Vega Formation in Spain, which may belong to ''Torvosaurus'' or a closely related taxon, is about 15% larger than the one found on ''T. gurneyi.'' It was the morphological distinctiveness of the holotype maxilla ML1100 that led to the naming of the Portuguese species. In 2017, a set of Portuguese cranial material assigned to ''Torvosaurus'' was described, including a specimen interpreted as belonging to the same individual as the holotype of ''Torvosaurus gurneyi''.

In 2020, Soto ''et al.'' described FC-DPV 2971, a tooth from Uruguay, as belonging to a new unnamed species of ''Torvosaurus''. They also assigned ''Megalosaurus''/''Ceratosaurus ingens'' (specimen MB R 1050) from Tanzania to ''Torvosaurus''. Also in 2020, a fragmentary maxilla referable to ''Torvosaurus'' was described from the middle Callovian Ornatenton Formation of Germany. This is the oldest record of the genus and suggests that megalosaurines originated in Europe, or at least that Europe was a biogeographical turntable for them from the Middle to the early Late Jurassic. Other possible ''Torvosaurus'' instances in Europe include fragmentary remains from the Kimmeridge Clay of England that possibly belong to the genus. These consist of a tibia (OUMNH J.29886) and a maxilla fragment that were collected separately from each other.

Description

''Torvosaurus'' was a very large and robust predatory dinosaur. ''T. tanneri'' was initially described as long, but a detailed osteological description has revised its length estimate to . ''T. gurneyi'' was initially estimated around long, but its body length estimate was revised to in its specific description. Claims have been made indicating even larger sizes for the American species ''T. tanneri'', with estimates of up to in length and more than based on incomplete remains of ''Edmarka rex'' and "Brontoraptor". However, ''Edmarka rex'' and "Brontoraptor" lack detailed analyses to verify whether or not they actually belong to ''T. tanneri''. ''T. tanneri'' is estimated to have weighed approximately , while ''T. gurneyi'' is estimated to have weighed .

Among the differentiating features originally recognized between ''T. gurneyi'' and ''T. tanneri'' are the number of teeth, alongside the size and shape of the mouth. While the upper jaw of ''T. tanneri'' has more than 11 teeth, that of ''T. gurneyi'' has less. However, later examination of a new right maxilla, probably belonging to the same individual as the holotype of ''T. gurneyi'', has determined that, while the two species can be distinguished based on the morphology of the maxillary medial wall and interdental plates, the supposedly lower number of maxillary teeth in the Portuguese form may be an artifact of preservation, since it is not possible to know the exact number of teeth in the complete maxilla at the moment.

The material from Germany is further distinguished by the other two species by a temporal difference of c. 10 Ma and a few morphological differences which indicate that it was the third species outside a sister taxon relationship between ''T. tanneri'' and ''T. gurneyi''. The material is only 10% smaller than the maxilla of ''T. tanneri'', although the ontogenetic stage of the specimen is unknown. This indicates that derived megalosaurines were already among the largest terrestrial predators of the late Middle Jurassic, with only a moderate increase in size in the genus by the Late Jurassic.
''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 in side 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, a condition by Britt likened to a Derby hat. The tail base was stiffened in the vertical plane by high and in side view wide neural spines. The whole of the arm was very strong, but somewhat 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.

Systematics and classification

When first described in 1979 by Galton and Jensen,P. M. Galton and J. A. Jensen. 1979
A new large theropod dinosaur from the Upper Jurassic of Colorado
. Brigham Young University Geology Studies 26(1):1–12 ''Torvosaurus'' was classified as a megalosaurid, which is the current consensus. It was later assigned to Carnosauria by Ralph Molnar ''et al.'' in 1990, then to a basal position in Spinosauroidea by Oliver Walter Mischa Rauhut in 2003, and to a very basal position in Tetanurae by Thomas Holtz in 1994. All these assignments are not supported by present phylogenetic analysis. In 1985, Jensen assigned ''Torvosaurus'' to a family of its own, Torvosauridae. Despite support for this concept by Paul Sereno and Mateus, it seems redundant because ''Torvosaurus'' is closely related to, and perhaps the sister species of, the earlier ''Megalosaurus'' within Megalosaurinae. However, Torvosauridae may be used as an alternative name for Megalosauridae if ''Megalosaurus'' is considered an indeterminable ''nomen dubium''. Though a close relative of ''Megalosaurus'', ''Torvosaurus'' is seemingly more advanced, or apomorphic. ''Torvosaurus''s larger clade, Megalosauridae, is most commonly held as a basal branch of Tetanurae, considered to be less derived than carnosaurs or coelurosaurs and likely related to the spinosaurids.

The following is a cladogram based on the phylogenetic analysis conducted by Carrano, Benson, and Sampson (2012) showing the relationships of ''Torvosaurus'':Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)". Journal of Systematic Palaeontology 10 (2): 211–300. doi:10.1080/14772019.2011.630927

Distinguishing anatomical features

According to Carrano ''et al.'' (2012), ''Torvosaurus'' can be distinguished based on the following characteristics:
* The presence of a very shallow maxillary fossa (it lacks a ''fenestra maxillaris'' piercing the bone wall)
* The presence of fused interdental plates
* The pneumatic fossae in the posterior dorsal and the anterior caudal vertebrae centra being expanded to form enlarged, deep openings
* The puboischiadic plate being highly ossified (the paired bony plates of both sides connect and close off the entire underside of the pelvis, a very basal trait that Galton & Jensen saw as an indication that Theropoda was polyphyletic, with Carnosauria having independently evolved from carnivorous Prosauropoda)
* A distal expansion of the ischium shaft with a prominent lateral midline crest and an ovalur outline when examined in lateral view
* The cervical vertebrae are opisthocoelous with a pronounced flat rim around the anterior ball (according to Rauhut, 2000)
* A transverse fenestra is situated in the neural arch of the dorsal vertebrae in front of the hyposphene (according to Rauhut, 2000)

Paleobiology

The study of fossilized embryos of ''Torvosaurus'' provides researchers with information about the transformation of the embryo over time, the different developmental pathways present in dinosaur lineages, dinosaur reproductive behavior, and dinosaur parental care. In 2013, Araújo ''et al''. announced the discovery of specimen ML1188, a clutch of crushed dinosaur eggs and embryonic material attributed to ''Torvosaurus''. This discovery further supports the hypothesis that large theropods were oviparous, meaning that they laid eggs and hence that embryonic development occurred outside the body of female dinosaurs. This discovery was made in 2005 by the Dutch amateur fossil-hunter Aart Walen at the Lourinhã Formation in Western Portugal in fluvial overbank sediments that are considered to be from the Tithonian age of the Jurassic, approximately 152 to 145 million years ago. This discovery is paleontologically significant for a number of reasons: (a) these are the most primitive dinosaur embryos known; (b) these are the only basal theropod embryos known; (c) fossilized eggs and embryos are rarely found together; (d) it represents the first evidence of a one-layered eggshell for theropod dinosaurs; and (e) it allows researchers to link a new eggshell morphology to the osteology of a particular group of theropod dinosaurs. The specimen is housed at the Museu da Lourinhã in Portugal. As the eggs were abandoned due to unknown circumstances, it is not known if ''Torvosaurus'' provided parental care to its eggs and young or abandoned them shortly after laying. However, the eggshells are highly porous, allowing efficient gaseous exchange between the external and internal media, thus indicating the eggs were buried for incubation within substrate in a manner similar to modern seaturtles. This is also corroborated by the undisturbed taphonomic setting and low-energy geological context.

All documented ''Torvosaurus'' specimens from the Morrison Formation are from similarly sized, likely adult individuals and the lack of immature individuals may be explained by many factors, none of which are mutually exclusive. For one thing, the formation is known to preserve large vertebrates better than smaller ones. Immature individuals may also have occupied a different ecological niche from adults in habitats where their remains were likely to preserve as fossils and they may have been the prey of choice of larger predators as well. ''Torvosaurus'' may also have experienced Type B1 population survivorship, as has been found in other dinosaurs, with mortality increasing after sexual maturity was achieved, leading to an abundance of mature individuals in the fossil record. A final possibility is that immature ''Torvosaurus'' remains could be misidentified due to having different proportions compared to the very large and robust adults.

Paleoecology

Provenance and occurrence

The type specimen of ''Torvosaurus tanneri'', BYU 2002, was recovered in the Dry Mesa Quarry of the Brushy Basin Member of the Morrison Formation in Montrose County, Colorado. The specimen was collected by James A. Jensen and Kenneth Stadtman in 1972 in medium-grained, coarse sandstone that was deposited during the Tithonian and Kimmeridgian ages of the Jurassic, approximately 153 to 148 million years ago. This specimen is housed in the collection of Brigham Young University in Provo, Utah.

Fauna and habitat in North America

Studies suggest that the paleoenvironment of this section of the Morrison Formation included rivers that flowed from the west into a basin that contained a giant, saline alkaline lake and there were extensive wetlands in the vicinity. The Dry Mesa Dinosaur Quarry of western Colorado yields one of the most diverse Upper Jurassic vertebrate assemblages in the world. The Dry Mesa Quarry has produced the remains of the sauropods ''Apatosaurus'', ''Brachiosaurus'', ''Diplodocus'', ''Barosaurus'', ''Supersaurus'', and ''Camarasaurus'', the iguanodonts ''Camptosaurus'' and ''Dryosaurus'', and the theropods ''Allosaurus'', ''Tanycolagreus'', '' Koparion'', ''Stokesosaurus'', ''Ceratosaurus'', and ''Ornitholestes'', as well as ''Othnielosaurus'', ''Gargoyleosaurus'', and ''Stegosaurus''.

The flora of the period has been revealed by fossils of green algae, fungi, mosses, horsetails, ferns, cycads, ginkgoes, and several families of conifers. Other animal fossils discovered include bivalves, snails, ray-finned fishes, frogs, salamanders, amphibians, turtles, sphenodonts, lizards, terrestrial (like '' Hoplosuchus'') and aquatic crocodylomorphs, cotylosaurs, several species of pterosaurs, like '' Harpactognathus'', and early mammals, such as multituberculates, symmetrodonts, and triconodonts.

Fauna and habitat in Europe

The Ornatenton Formation is a Callovian aged shallow marine deposit, within the formation ''Torvosaurus'' was sympatric with the closely related and also large ''Wiehenvenator.'' The Lourinhã Formation is Kimmeridgian-Tithonian in age. The environment is coastal and therefore has a strong marine influence. Its flora and fauna are very similar to that of the Morrison. ''Torvosaurus'' appears to be the top predator here. It lived alongside the European species of ''Allosaurus'' (''A. europaeus''), ''Ceratosaurus'', ''Stegosaurus'', and presumably ''Camptosaurus''. The theropod ''Lourinhanosaurus'' also stalked the area. ''Lusotitan'' was the largest sauropod in the region, while the diplodocids ''Dinheirosaurus'' and '' Lourinhasaurus'' were also present. ''Dacentrurus'' and ''Miragaia'' were both stegosaurs, while ''Dracopelta'' was an ankylosaurian. ''Draconyx'' was an iguanodontid related to ''Camptosaurus''. Due to the marine nature of the Lourinhã Formation, sharks, plesiochelyid turtles, and teleosaurid crocodyliforms are also present.

Fauna and habitat in Africa

The small-scale trough and ripple cross-bedded fine-grained sandstone at the base of the Upper Dinosaur Member of the Tendaguru Formation, of which possible ''Torvosaurus'' material is known from, is interpreted as tidal flat deposits. Stagnant water bodies, such as small lakes and ponds, were present and a freshwater depositional environment close to the sea was also probably present.

The possible unnamed ''Torvosaurus'' species from the Tendaguru Formation would have shared its habitat with many species of sauropods, such as ''Australodocus'', ''Dicraeosaurus'', ''Giraffatitan'', ''Janenschia'', ''Tornieria'', ''Wamweracaudia'', three unnamed species of diplodocine sauropods, an unnamed species of flagellicaudatan, and "The Archbishop". The theropods it coexisted with were '' Allosaurus tendagurensis'', '' Ceratosaurus roechlingi'', ''Elaphrosaurus'', '' Labrosaurus stechowi'', ''Ostafrikasaurus'', '' Veterupristisaurus'' (of which it would have possibly competed with to be top predator), a possible abelisauroid, and an indeterminate megalosauroid, while the ornithischians it coexisted with were '' Dysalotosaurus'' and ''Kentrosaurus''. As far as pterosaurs are concerned, it coexisted with '' Tendaguripterus'', an indeterminate archaeopterodactyloid, an indeterminate azhdarchid, two indeterminate dsungaripteroids, an indeterminate rhamphorynchoid, and an indeterminate pterosaur of unknown classification. Due to the coastal environment of the Tendaguru Formation, crocodyliformes, such as ''Bernissartia'', amphibians, including an unnamed lissamphibian, and sharks are also present.

Fauna and habitat in South America

Within South America, possible ''Torvosaurus'' remains are only present within the Tacuarembó Formation of Uruguay. Because the formation was laid down in fluvial to lacustrine sandstones, siltstones, and mudstones, this indicates that the environment of the formation would have been dominated by rivers, streams, and lakes.

If present, ''Torvosaurus'' would probably have been the apex predator in the Tacuarembó Formation, although it may have been rivalled by ''cf. Ceratosaurus''. It shared its habitat with two unnamed theropods, an unnamed coelurosaur, an unnamed sauropod known solely from footprints, an unnamed ornithopod also known from footprints, an indeterminate mesoeucrocodylian, an indeterminate turtle species that lived alongside the named turtle species '' Tacuarembemys kusterae'', and the possible pholidosaur '' Meridiosaurus vallisparadisi''. Fish, such as '' Arganodus tiguidiensis'', '' Asiatoceratodus cf. tiguidensis'', '' Neoceratodus africanus'', and '' Priohybodus arambourgi'', and bivalves, such as '' Diplodon'', are also present.

Coexistence with other large carnivores

''Torvosaurus'' coexisted with other large theropods such as ''Allosaurus'' and ''Ceratosaurus'' in the United States and Portugal, possibly '' Veterupristisaurus'' in Tanzania, and possibly ''cf. Ceratosaurus (?)'' in Uruguay. The three, possibly four, species appear to have had different ecological niches, based on anatomy and the location of fossils. ''Torvosaurus'' and ''Ceratosaurus'' may have preferred to be active around waterways and had lower, more sinuous, bodies that would have given them an advantage in forest and underbrush terrains, whereas ''Allosaurus'' had shorter bodies, longer legs, were faster and less maneuverable, and seem to have preferred dry floodplains. Also, Rauhut et al. (2016) proposed that allosaurids and megalosaurids would have had different environmental preferences, the former being more common in inland areas, while the latter being dominant in marine and coastal environments.

On the other hand, the majority of ''Torvosaurus'' remains from the Morrison Formation have been found in localities preserving multiple taxa, including ''Allosaurus,'' with ''Torvosaurus'' itself being a minor component of the bonebeds. This pattern has been interpreted as indicative of ''Torvosaurus'' sharing habitats with other predators, most notably ''Allosaurus'', but at much lower abundances. The three may also have had different dietary preferences, with ''Allosaurus'' being more suited for bone slicing (thanks to its short and stout serrated teeth, deep and narrow skull, and powerful dorsoventral movement capacity of the neck), while ''Ceratosaurus,'' with its long and blade-like teeth and relatively straight neck, would have probably been incapable of doing so, instead concentrating on the deepest organs of a carcass. While probably capable of some bone consumption, ''Torvosaurus,'' with its large skull and teeth and large, powerful, and lithe body may have been specialized in opening up and dismembering exceptionally large sauropod carcasses. This would have allowed smaller theropods, like ''Allosaurus'', better access in a possible commensalism relationship.

''Allosaurus'' was itself a potential food item to other carnivores, as illustrated by an ''Allosaurus'' pubic foot marked by the teeth of another theropod, probably ''Ceratosaurus'' or ''Torvosaurus''. The location of the bone in the body (along the bottom margin of the torso and partially shielded by the legs) and the fact that it was among the most massive in the skeleton indicates that the ''Allosaurus'' was being scavenged.

Bite marks on ''Allosaurus'' and ''Mymoorapelta'' remains were found among other bones with feeding traces in the Upper Jurassic Mygatt-Moore Quarry. Unlike the others, these have left striations that, when measured to determine denticle width, produced tooth and body size extrapolations greater than any known specimen of ''Allosaurus'' or ''Ceratosaurus'', the two large predators known for osteological remains from the quarry. The extrapolations are instead coherent, either with an unusually large specimen of ''Allosaurus'' or a separate large taxon like ''Torvosaurus'' which is not known from the quarry. The result either increases the known diversity of the site based on ichnological evidence alone or represents powerful evidence of cannibalism in ''Allosaurus''. Based on the position and nutrient value associated with the various skeletal elements with bite marks, it is predicted that while ''Mymoorapelta'' was either predated upon or scavenged shortly after death, ''Allosaurus'' was scavenged some time after death.

References

External links

''Largest Predatory Dinosaur in Europe Found'' at nationalgeographic

{{Taxonbar, from=Q131537

Megalosauridae
Dinosaur genera
Jurassic dinosaurs
Morrison Formation
Lourinhã Formation
Taxa named by Peter Galton
Taxa named by James A. Jensen
Fossil taxa described in 1979
Dinosaurs of the United States
Dinosaurs of Portugal