Allosaurus - Knowledge

3832:

this conclusion. The researchers found a positive association between allosaurids and fractures to the appendicular skeleton, while tyrannosaurs had a statistically negative association with these types of injuries. The fact that allosaurs were more likely to survive and heal even when severe fractures limited their locomotion abilities can be explained, in part, by different resource accessibility paradigms for the two groups, as allosauroids generally lived in sauropod-inhabited ecosystems, some of which, including the Morrison, have been interpreted as arid and highly water-stressed environments; however, the water-stressed nature of the Morrison has been heavily criticized in several more recent works on the basis of fossil evidence for the presence of extensive forest cover and aquatic ecosystems.

3446: 3682:, which is thought to have been capable of damaging bones. They also suggested that the architecture of the skull could have permitted the use of different strategies against different prey; the skull was light enough to allow attacks on smaller and more agile ornithopods, but strong enough for high-impact ambush attacks against larger prey like stegosaurids and sauropods. Their interpretations were challenged by other researchers, who found no modern analogs to a hatchet attack and considered it more likely that the skull was strong to compensate for its open construction when absorbing the stresses from struggling prey. The original authors noted that 12904: 15036: 3760: 4581: 12897: 2890: 11401: 2434: 1048: 12226: 12212: 3529: 14488: 13692: 14474: 12205: 14481: 2324: 11407: 10818: 3973: 1236: 12911: 2254: 144: 12219: 2634: 4097: 15049: 13710: 3641: 2131: 119: 10829: 13698: 13717: 15043: 4035:" and occurred across all three weight-bearing toes in "statistically indistinguishable" numbers. Since the lower end of the third metatarsal would have contacted the ground first while an allosaur was running, it would have borne the most stress. If the allosaurs' stress fractures were caused by damage accumulating while walking or running this bone should have experience more stress fractures than the others. The lack of such a bias in the examined 14468: 3191: 10806: 4223: 2553: 2954: 3915: 3562: 1154: 3214: 726: 1628: 4306: 13705: 3860:

that adult allosaurs brought food to lairs for their young to eat until they were grown, and prevented other carnivores from scavenging on the food. However, there is actually little evidence of gregarious behavior in theropods, and social interactions with members of the same species would have included antagonistic encounters, as shown by injuries to gastralia and bite wounds to skulls (the pathologic lower jaw named

2873: 3236: 10743: 749: 3039: 3841: 3136: 1807: 1578: 2991: 2464:(the tooth-bearing bone of the lower jaw) had between 14 and 17 teeth, with an average count of 16. The teeth became shorter, narrower, and more curved toward the back of the skull. All of the teeth had saw-like edges. They were shed easily, and were replaced continually, making them common fossils. Its skull was light, robust and equipped with dozens of sharp, 2292:, James H. Madsen mentioned a range of bone sizes which he interpreted to show a maximum length of 12 to 13 m (39 to 43 ft). As with dinosaurs in general, weight estimates are debatable, and since 1980 have ranged between 1.5 metric tons (1.7 short tons), 1 to 4 metric tons (1.1 to 4.4 short tons), and approximately 1 metric ton (1.1 short tons) for 2401:(Utah) specimens found no justification for multiple species based on skeletal variation; skull variation was most common and was gradational, suggesting individual variation was responsible. Further work on size-related variation again found no consistent differences, although the Dry Mesa material tended to clump together on the basis of the 2312:, researchers using computer modeling arrived at a best estimate of 1.5 metric tons (1.7 short tons) for the individual, but by varying parameters they found a range from approximately 1.4 metric tons (1.5 short tons) to approximately 2 metric tons (2.2 short tons). A separate computational project estimated the adaptive optimum body mass in 9810: 3789:. As with crocodilians, this may have been enough to judge prey distance and time attacks. The arms, compared with those of other theropods, were suited for both grasping prey at a distance or clutching it close, and the articulation of the claws suggests that they could have been used to hook things. Finally, the top speed of 3744:. This would have allowed the animal to make rapid and forceful vertical movements with the skull. The authors found that vertical strikes as proposed by Bakker and Rayfield are consistent with the animal's capabilities. They also found that the animal probably processed carcasses by vertical movements in a similar manner to 1223:, a severe bone infection. A particular problem for the living animal was infection and trauma to the right foot that probably affected movement and may have also predisposed the other foot to injury because of a change in gait. "Big Al" had an infection on the first phalanx on the third toe that was afflicted by an 2668:. Of the three fingers, the innermost (or thumb) was the largest, and diverged from the others. The phalangeal formula is 2-3-4-0-0, meaning that the innermost finger (phalange) has two bones, the next has three, and the third finger has four. The legs were not as long or suited for speed as those of 1144:

topics). Such studies have covered topics including skeletal variation, growth, skull construction, hunting methods, the brain, and the possibility of gregarious living and parental care. Reanalysis of old material (particularly of large 'allosaur' specimens), new discoveries in Portugal, and several

1107:

remains has allowed this genus to be known in great detail, making it among the best-known of all theropods. Skeletal remains from the quarry pertain to individuals of almost all ages and sizes, from less than 1 metre (3.3 feet) to 12 metres (39 feet) long, and the disarticulation is an advantage for

3996:

dinosaurs and the implications for their behavior. Since stress fractures are caused by repeated trauma rather than singular events they are more likely to be caused by the behavior of the animal than other kinds of injury. Stress fractures and tendon avulsions occurring in the forelimb have special

3694:

were "flesh grazers" which could take bites of flesh out of living sauropods that were sufficient to sustain the predator so it would not have needed to expend the effort to kill the prey outright. This strategy would also potentially have allowed the prey to recover and be fed upon in a similar way

3616:

was probably not a predator of fully grown sauropods, unless it hunted in packs, as it had a modestly sized skull and relatively small teeth, and was greatly outweighed by contemporaneous sauropods. Another possibility is that it preferred to hunt juveniles instead of fully grown adults. Research in

3859:

preyed on sauropods and other large dinosaurs by hunting in groups. Such a depiction is common in semitechnical and popular dinosaur literature. Robert T. Bakker has extended social behavior to parental care, and has interpreted shed allosaur teeth and chewed bones of large prey animals as evidence

3699:

may have subdued them by using an attack similar to that of modern big cats: grasping the prey with their forelimbs, and then making multiple bites on the throat to crush the trachea. This is compatible with other evidence that the forelimbs were strong and capable of restraining prey. Studies done

2798:

Following the publication of Madsen's influential monograph, Allosauridae became the preferred family assignment, but it too was not strongly defined. Semi-technical works used Allosauridae for a variety of large theropods, usually those that were larger and better-known than megalosaurids. Typical

3893:

individuals were drawn together to feed on other disabled or dead allosaurs, and were sometimes killed in the process. This could explain the high proportion of juvenile and subadult allosaurs present, as juveniles and subadults are disproportionally killed at modern group feeding sites of animals

3831:

It has also been argued that disabled individuals such as Big Al and Big Al II were physically incapable of hunting due to their numerous injuries but were able to survive nonetheless as scavengers of giant sauropod-falls, Interestingly, a recent review of paleopathologies in theropods may support

3880:

carnivores (including lizards, crocodiles, and birds) rarely cooperate to hunt in such a way. Instead, they are typically territorial and will kill and cannibalize intruders of the same species, and will also do the same to smaller individuals that attempt to eat before they do when aggregated at

3548:

became thicker and wider during growth, and the cross-section less circular, as muscle attachments shifted, muscles became shorter, and the growth of the leg slowed. These changes imply that juvenile legs has less predictable stresses compared with adults, which would have moved with more regular

2487:

sheath and may have had a variety of functions, including acting as sunshades for the eyes, being used for display, and being used in combat against other members of the same species (although they were fragile). There was a ridge along the back of the skull roof for muscle attachment, as is also

1102:

of the site, suggesting numerous mutually exclusive explanations for how it may have formed. Suggestions have ranged from animals getting stuck in a bog, becoming trapped in deep mud, falling victim to drought-induced mortality around a waterhole, and getting trapped in a spring-fed pond or seep.

3875:

and other theropods had largely aggressive interactions instead of cooperative interactions with other members of their own species. The study in question noted that cooperative hunting of prey much larger than an individual predator, as is commonly inferred for theropod dinosaurs, is rare among

2164:

in the second edition of the Dinosauria, subsequent studies place it as indeterminate beyond Tetanurae, either a carcharodontosaurian or megalosaurid. Although obscure, it was a large theropod, possibly around 10 metres (33 ft) long and 2.5 tonnes (2.5 long tons; 2.8 short tons) in weight.

1439:

However, subsequent analysis of specimens from the Cleveland-Lloyd Dinosaur Quarry, Como Bluff, and Dry Mesa Quarry showed that the differences seen in the Morrison Formation material could be attributed to individual variation. A study of skull elements from the Cleveland-Lloyd site found wide

1357:

has been scientifically described based on two nearly complete skeletons. The first specimen to wear the identification was unearthed in Dinosaur National Monument in northeastern Utah, with the original "Big Al" individual subsequently recognized as belonging to the same species. This species

4059:

specimen cataloged as USNM 4734 are both pathological, both probably due to healed fractures. The specimen USNM 8367 preserved several pathological gastralia which preserve evidence of healed fractures near their middle. Some of the fractures were poorly healed and "formed pseudoarthroses". A

3812:

sauropods when available, with the scarcity of such bite marks on the remains of smaller bones being potentially attributable to much more complete consumption of smaller or adolescent sauropods and on ornithischians, which would have been more commonly taken as live prey. A single dead adult

3811:

at all stages of decomposition, indicating that late-stage decay pathogens were not a significant deterrent. A survey of sauropod bones from the Morrison Formation also reported widespread bite marks on sauropod bones in low-economy regions, which suggests that large theropods scavenged large

2704:

measuring 1–3 mm in diameter. A skin impression from the "Big Al Two" specimen, associated with the base of the tail, measures 20 cm x 20 cm and shows large scales measuring up to 2 cm in diameter. However, it has been noted that these scales are more similar to those of

4039:

fossils indicates an origin for the stress fractures from a source other than running. The authors conclude that these fractures occurred during interaction with prey, like an allosaur trying to hold struggling prey with its feet. The abundance of stress fractures and avulsion injuries in

3752:: the animal could have gripped prey with the skull and feet, then pulled back and up to remove flesh. This differs from the prey-handling envisioned for tyrannosaurids, which probably tore flesh with lateral shakes of the skull, similar to crocodilians. In addition, 4068:

was reported to have extensive pathologies, with a total of fourteen separate injuries. The specimen MOR 693 had pathologies on five ribs, the sixth neck vertebra, the third, eighth, and thirteenth back vertebrae, the second tail vertebra and its chevron, the

3539:

The discovery of a juvenile specimen with a nearly complete hindlimb shows that the legs were relatively longer in juveniles, and the lower segments of the leg (shin and foot) were relatively longer than the thigh. These differences suggest that younger

1533: 1930) being extremely fragmentary, consisting of a few incomplete vertebrae, limb fragments, rib fragments, and a single tooth. Because of this, several scientists have interpreted the type specimen as potentially dubious, meaning the genus 2535:

for the brain. The skull and lower jaws had joints that permitted motion within these units. In the lower jaws, the bones of the front and back halves loosely articulated, permitting the jaws to bow outward and increasing the animal's gape. The

2409:, using skull elements from the Cleveland-Lloyd site, found wide variation between individuals, calling into question previous species-level distinctions based on such features as the shape of the horns, and the proposed differentiation of 4028:. Of the 47 hand bones the researchers studied, three were found to contain stress fractures. Of the feet, 281 bones were studied and 17 were found to have stress fractures. The stress fractures in the foot bones "were distributed to the 4690:. The unusually high concentration of theropod bite marks compared to other assemblages could be explained either by a more complete utilization of resources during a dry season by theropods, or by a collecting bias in other localities. 10293:

Bakker, Robert T.; Bir, Gary (2004). "Dinosaur crime scene investigations: theropod behavior at Como Bluff, Wyoming, and the evolution of birdness". In Currie, Philip J.; Koppelhus, Eva B.; Shugar, Martin A.; Wright, Joanna L. (eds.).

7086:

Bakker, 1997. Raptor family values: Allosaur parents brought great carcasses into their lair to feed their young. In Wolberg, Sump and Rosenberg (eds). Dinofest International, Proceedings of a Symposium, Academy of Natural Sciences.

679:, with the largest specimens estimated as being 9.7 metres (32 ft) long. Relative to the large and powerful legs, its three-fingered hands were small and the body was balanced by a long, muscular tail. It is classified as an 6881: 3722:

had a wider gape than either; the animal was capable of opening its jaws to a 92-degree angle at maximum. The findings also indicate that large carnivorous dinosaurs, like modern carnivores, had wider jaw gapes than herbivores.

1215:, as it was a subadult estimated at only 87% grown. The specimen was described by Breithaupt in 1996. Nineteen of its bones were broken or showed signs of serious infection, which may have contributed to "Big Al's" death. 4077:

metatarsals III and V, the first phalanx of the third toe and the third phalanx of the second. The ilium had "a large hole...caused by a blow from above". The near end of the first phalanx of the third toe was afflicted by an

1471: 10414:

Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p.

10621:

Mateus, Octávio (2006). "Jurassic dinosaurs from the Morrison Formation (USA), the Lourinhã and Alcobaça Formations (Portugal), and the Tendaguru Beds (Tanzania): A comparison". In Foster, John R.; Lucas, Spencer G. (eds.).

6390:

Mateus, Octávio; Walen, Aart; Antunes, Miguel Telles (2006). "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

8570:

Hendrickx, Christophe; Bell, Phil R.; Pittman, Michael; Milner, Andrew R. C.; Cuesta, Elena; O'Connor, Jingmai; Loewen, Mark; Currie, Philip J.; Mateus, Octávio; Kaye, Thomas G.; Delcourt, Rafael (June 2022).

3637:-like cutting edge running the length of the upper jaw, which would have been driven into prey. This type of jaw would permit slashing attacks against much larger prey, with the goal of weakening the victim. 1615:

by Marsh for an oddly formed partial lower jaw, with a prominent gap in the tooth row at the tip of the jaw, and a rear section greatly expanded and turned down. Later researchers suggested that the bone was

4005:

was one of only two theropods examined in the study to exhibit a tendon avulsion, and in both cases the avulsion occurred on the forelimb. When the researchers looked for stress fractures, they found that

838:

1930, a small collection of fragmentary bones including parts of three vertebrae, a rib fragment, a tooth, a toe bone, and (most useful for later discussions) the shaft of the right humerus (upper arm).

707:

and hunting in packs, while others believe individuals may have been aggressive toward each other and that congregations of this genus are the result of lone individuals feeding on the same carcasses.

3820:

would have had enough calories to sustain multiple large theropods for weeks or months, though the vast majority of the Morrison's sauropod fossil record consisted of much smaller-bodied taxa such as

10572:

Chure, Daniel J.; Litwin, Ron; Hasiotis, Stephen T.; Evanoff, Emmett; Carpenter, Kenneth (2006). "The fauna and flora of the Morrison Formation: 2006". In Foster, John R.; Lucas, Spencer G. (eds.).

4662:. 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 3670:

skull. According to their biomechanical analysis, the skull was very strong but had a relatively small bite force. By using jaw muscles only, it could produce a bite force of 805 to 8,724

5851:

Bakker, Robert T. (1997). "Raptor Family values: Allosaur parents brought giant carcasses into their lair to feed their young". In Wolberg, Donald L.; Sump, Edmund; Rosenberg, Gary D. (eds.).

3686:

itself has no modern equivalent, that the tooth row is well-suited to such an attack, and that articulations in the skull cited by their detractors as problematic actually helped protect the

3509:

individual has been used to establish sex and show it had reached reproductive age. However, other studies have called into question some cases of medullary bone in dinosaurs, including this

883:, meaning "lizard" or "reptile". It was named 'different lizard' because its vertebrae were different from those of other dinosaurs known at the time of its discovery. The species epithet 3629:

saber-toothed carnivorous mammals, found similar adaptations, such as a reduction of jaw muscles and increase in neck muscles, and the ability to open the jaws extremely wide. Although

3612:, based on the presence of scrapings on sauropod bones fitting allosaur teeth well and the presence of shed allosaur teeth with sauropod bones. However, as Gregory Paul noted in 1988, 3460:

fossils, from nearly all ages of individuals, allows scientists to study how the animal grew and how long its lifespan may have been. Remains may reach as far back in the lifespan as

1440:

variation between individuals, calling into question previous species-level distinctions based on such features as the shape of the lacrimal horns and the proposed differentiation of

1098:

have been found there, out of at a minimum 73 dinosaurs) and the fossils found there are disarticulated and well-mixed. Nearly a dozen scientific papers have been written on the

954:(several years after Cope had died), it was found to be one of the most complete theropod specimens then known and the skeleton, now cataloged as AMNH 5753, was put on public view in 8384:

Madsen, 1976; note that not everyone agrees on where the neck ends and the back begins, and some authors such as Gregory S. Paul interpret the count as 10 neck and 13 back vertebrae.

2622:

had a prominent foot that may have been used for both muscle attachment and as a prop for resting the body on the ground. Madsen noted that in about half of the individuals from the

4666:

was being scavenged. A bone assemblage in the Upper Jurassic Mygatt-Moore Quarry preserves an unusually high occurrence of theropod bite marks, most of which can be attributed to

2217:, but the original authors defended their identification. With fifteen years of new specimens and research to look at, Daniel Chure reexamined the bone and found that it was not 975:

The multiplicity of early names complicated later research, with the situation compounded by the terse descriptions provided by Marsh and Cope. Even at the time, authors such as

4682:

given the size of the striations. While the position of the bite marks on the herbivorous dinosaurs is consistent with predation or early access to remains, bite marks found on

2700:

have been described. One impression, from a juvenile specimen, measures 30 cm² and is associated with the anterior dorsal ribs/pectoral region. The impression shows small

2648:

were short in comparison to the hindlimbs (only about 35% the length of the hindlimbs in adults) and had three fingers per hand, tipped with large, strongly curved and pointed

687:

was at the top of the food chain and probably preyed on contemporaneous large herbivorous dinosaurs, with the possibility of hunting other predators. Potential prey included

6882:"Opinion 2486 (Case 3506) – Allosaurus Marsh, 1877 (Dinosauria, Theropoda): usage conserved by designation of a neotype for its type species Allosaurus fragilis Marsh, 1877" 3633:

did not have saber teeth, Bakker suggested another mode of attack that would have used such neck and jaw adaptations: the short teeth in effect became small serrations on a

7330: 1620:, showing an injury to the living animal, and that part of the unusual form of the rear of the bone was due to plaster reconstruction. It is now regarded as an example of 903:, who were in scientific competition with each other, went on to coin several other genera based on similarly sparse material that would later figure in the taxonomy of 922:

In their haste, Cope and Marsh did not always follow up on their discoveries (or, more commonly, those made by their subordinates). For example, after the discovery by

9121:"Pathological Bone Tissues in a Turkey Vulture and a Nonavian Dinosaur: Implications for Interpreting Endosteal Bone and Radial Fibrolamellar Bone in Fossil Dinosaurs" 10591:

Dodson, Peter; Behrensmeyer, A.K.; Bakker, Robert T.; McIntosh, John S. (1980). "Taphonomy and paleoecology of the dinosaur beds of the Jurassic Morrison Formation".

8965:"Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs" 3544:

were faster and had different hunting strategies than adults, perhaps chasing small prey as juveniles, then becoming ambush hunters of large prey upon adulthood. The

4623:

may have preferred to be active around waterways, and had lower, thinner bodies that would have given them an advantage in forest and underbrush terrains, whereas

1736: 3807:

Sauropod carrion may also have been important to large theropods in the Morrison Formation. Forensic techniques indicate that sauropod carcasses were targeted by

5715:

Rayfield, Emily J.; Norman, DB; Horner, CC; Horner, JR; Smith, PM; Thomason, JJ; Upchurch, P (2001). "Cranial design and function in a large theropod dinosaur".

1857:

by Oliver Hay in 1902, but Hay later clarified that this was an inexplicable error on his part. Gilmore considered the tooth nondiagnostic but transferred it to

6134: 972:. Although notable as the first free-standing mount of a theropod dinosaur and often illustrated and photographed, it has never been scientifically described. 2680:, which Madsen suggested could have been used for grasping in juveniles. There was also what is interpreted as the splint-like remnant of a fifth (outermost) 5349: 1431:

is regarded as the most common, known from the remains of at least 60 individuals. For a while in the late 1980s and early 1990s, it was common to recognize

9765:"Application of forensic science techniques to trace fossils on dinosaur bones from a quarry in the Upper Jurassic Morrison Formation, Northeastern Wyoming" 3906:

shed teeth found among rib fragments, possible tooth marks on a shoulder blade, and cannibalized allosaur skeletons among the bones at Bakker's lair sites.

2366:(AMNH 5767), may have measured 12.1 metres (40 feet) in length. A more recent discovery is a partial skeleton from the Peterson Quarry in Morrison rocks of 1996:

was due to correspondence to Ralph Molnar by John McIntosh, whereby the latter reportedly found a paper saying that Othniel Charles Marsh admitted that the

2460:(the main tooth-bearing bones in the upper jaw) had between 14 and 17 teeth; the number of teeth does not exactly correspond to the size of the bone. Each 10643:"Prey bone utilization by predatory dinosaurs in the Late Jurassic of North America, with comments on prey bone use by dinosaurs throughout the Mesozoic" 3678:

used its skull like a machete against prey, attacking open-mouthed, slashing flesh with its teeth, and tearing it away without splintering bones, unlike

1790:

and are housed in the Tate Geological Museum. However, there has been no official description of the remains and "Wyomingraptor" has been dismissed as a

1671:, and is based on YPM 1890, an assortment of bones that includes a couple of pieces of the skull, portions of nine tail vertebrae, two hip vertebrae, an 1558: 2709:, and due to the presence of non-theropod remains associated with the tail of "Big Al Two" there is a possibility that this skin impression is not from 1211:

The completeness, preservation, and scientific importance of this skeleton gave "Big Al" its name. The individual itself was below the average size for

1090:

remains, the condition of the specimens, and the lack of scientific resolution on how it came to be. The majority of bones belong to the large theropod

7948:

Hocknull, Scott A.; White, Matt A.; Tischler, Travis R.; Cook, Alex G.; Calleja, Naomi D.; Sloan, Trish; Elliott, David A. (2009). Sereno, Paul (ed.).

6530: 4093:

has been discovered in Dana Quarry in Wyoming. This finding represents the first known fossil evidence of spondyloarthropathy occurring in a theropod.

7794:

Molnar, Ralph E.; Flannery, Timothy F.; Rich, Thomas H.V. (1981). "An allosaurid theropod dinosaur from the Early Cretaceous of Victoria, Australia".

3478:. From the same analysis, its maximum growth appears to have been at age 15, with an estimated growth rate of about 150 kilograms (330 1679:

thesis on Allosauridae noted that Charles Gilmore mistakenly reconstructed USNM 4734 as having a shorter skull than the specimens referred by Paul to

10753: 9811:"Further analysis of a Late Jurassic dinosaur bone-bed from the Morrison Formation of Montana, USA, with a computed three-dimensional reconstruction" 2724:, showing scales measuring 1–2 mm in diameter. The same fossil also preserves skin impressions from the ventral side of the neck, showing broad 2276:, the best-known species, had an average length of 8.5 m (28 ft) and mass of 1.7 metric tons (1.9 short tons), with the largest definitive 10782: 3517:

individual may have been the result of a bone pathology instead. However, with the confirmation of medullary tissue indicating sex in a specimen of

15265: 2397:(Colorado), but the shapes of the bones themselves did not vary between the sites. A later study by Smith incorporating Garden Park (Colorado) and 10674:"High frequencies of theropod bite marks provide evidence for feeding, scavenging, and possible cannibalism in a stressed Late Jurassic ecosystem" 5038: 3472:

analysis of limb bones, bone deposition appears to stop at around 22 to 28 years, which is comparable to that of other large theropods like

2779:

in publications that predate James Madsen's 1976 monograph. Major publications using the name "Megalosauridae" instead of "Allosauridae" include

1675:, and ankle and foot bones. Although the idea of two common Morrison allosaur species was followed in some semi-technical and popular works, the 9024: 8573:"Morphology and distribution of scales, dermal ossifications, and other non-feather integumentary structures in non-avialan theropod dinosaurs" 7466:

Olshevsky, G., 1991, A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia. Mesozoic Meanderings 2, 196 pp

6220:"Review of Pathologies on MOR 693: An Allosaurus from the Late Jurassic of Wyoming and Implications for Understanding Allosaur Immune Systems" 1943:

was described in 1914 by A. N. Riabinin on the basis of a bone, later identified as a partial fourth metatarsal, from the Early Cretaceous of

1039:" has been used informally for convenience when distinguishing between the skull Gilmore restored and the composite skull restored by Madsen. 15200: 8443: 7366:

Molnar, Ralph E.; Kurzanov, Sergei M.; Dong Zhiming (1990). "Carnosauria". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.).

9477: 9168: 2578:

estimated about 50, while Gregory S. Paul considered that to be too many and suggested 45 or less. There were hollow spaces in the neck and

15255: 15230: 5975:

Pérez-Moreno, B.P.; Chure, D. J.; Pires, C.; Marques Da Silva, C.; Dos Santos, V.; Dantas, P.; Povoas, L.; Cachao, M.; Sanz, J. L. (1999).

2345: 2232: 9691:

Christiansen, Per (1998). "Strength indicator values of theropod long bones, with comments on limb proportions and cursorial potential".

8047: 10778: 3864:

is one such possible example). Such head-biting may have been a way to establish dominance in a pack or to settle territorial disputes.

661:" to prominence. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. 15210: 10768: 9618: 9213:

Carpenter, Kenneth; Sanders, Frank; McWhinney, Lorrie A.; Wood, Lowell (2005). "Evidence for predator-prey relationships: Examples for

5825: 5804: 5566: 2452:

gives a length of 845 mm (33.3 in) for a skull belonging to an individual he estimates at 7.9 m (26 ft) long. Each

2060:, but that name was already in use, leading Chure to propose a substitute. Smith, in his 1998 analysis of variation, concluded that 15128: 9746: 8009:"A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: Evidence for their Gondwanan affinities" 7291: 6456:; Molnar, Ralph E.; Currie, Philip J. (2004). "Basal Tetanurae". In Weishampel David B.; Dodson, Peter; Osmólska, Halszka (eds.). 8212: 5976: 1185: 2056:, a taxon created by Chure in 1995 for giant allosaurid remains from the Morrison of Oklahoma. These remains had been known as 15250: 3800:

and how it worked has deemed the hatchet jaw attack unlikely, reinterpreting the unusually wide gape as an adaptation to allow

2614:(wishbone) was also present, but has only been recognized since 1996; in some cases furculae were confused with gastralia. The 2284:

680) estimated at 9.7 metres (32 feet) long, with an estimated weight of 2.3–2.7 metric tons (2.5–3.0 short tons). In his 1976

10821: 9848:

Lei, Roberto; Tschopp, Emanuel; Hendrickx, Christophe; Wedel, Mathew J.; Norell, Mark; Hone, David W. E. (November 14, 2023).

9530:"Allosaurus fed more like a falcon than a crocodile: Engineering, anatomy work reveals differences in dinosaur feeding styles" 8195:

Bates, Karl T.; Falkingham, Peter L.; Breithaupt, Brent H.; Hodgetts, David; Sellers, William I.; Manning, Phillip L. (2009).

1545:("dubious name", based on a specimen too incomplete to compare to other specimens or to classify). To address this situation, 1308:

is the type species and was named by Marsh in 1877. It is known from the remains of at least 60 individuals, all found in the

10530: 10303: 10196: 9230: 8822: 8789: 8683: 8654: 8171: 7778: 7492: 7375: 6690: 6632: 6465: 5956: 5924: 5860: 5523:

Loewen, Mark A.; Sampson, Scott D.; Carrano, Matthew T.; Chure, Daniel J. (2003). "Morphology, taxonomy, and stratigraphy of

5170: 5139: 4877: 7744:

Kurzanov, Sergei S.; Efimov, Mikhail B.; Gubin, Yuri M. (2003). "New archosaurs from the Jurassic of Siberia and Mongolia".

6372:

from the Morrison Formation of Dinosaur National Monument (Utah–Colorado) and a revision of the theropod family Allosauridae

6081:

from the Jurassic Morrison Formation, eastern Bighorn Basin, Wyoming". In Brown, C.E.; Kirkwood, S.C.; Miller, T.S. (eds.).

3804:

to deliver a muscle-driven bite to large prey, with the weaker jaw muscles being a trade-off to allow for the widened gape.

2176:, but did not or could not assign a species to them). They were reclassified as an indeterminate theropod. Also, reports of 15205: 12903: 12896: 10884: 4954: 2582:

back vertebrae. Such spaces, which are also found in modern theropods (that is, the birds), are interpreted as having held

1302:

does not show any unique characters compared to the North American species, so a reevaluation of its validity is required.

15035: 2630:, with females lacking fused bones to make egg-laying easier. This proposal has not attracted further attention, however. 2348:

1708) reached perhaps 10.5 m (34 ft) in length, and its single species has sometimes been included in the genus

2093:

was named by Lull in 1911 for a vertebra from the Early Cretaceous of Maryland. It is now regarded as a dubious theropod.

891:

for "fragile", referring to lightening features in the vertebrae. The bones were collected from the Morrison Formation of

10863: 10810: 10501:

Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A

8843:"A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic" 8138:

Paleoecological Analysis of the Vertebrate Fauna of the Morrison Formation (Upper Jurassic), Rocky Mountain Region, U.S.A

6142: 4541:

influence. Many of the dinosaurs of the Morrison Formation are the same genera as those seen in Portuguese rocks (mainly

3771: 3674:, but the skull could withstand nearly 55,500 N of vertical force against the tooth row. The authors suggested that 1988:. However, it was considered indeterminate beyond Dinosauria by Chure, and Mickey Mortimer believes that the synonymy of 10184: 8912:

Holtz, Thomas R. Jr. (1994). "The phylogenetic position of the Tyrannosauridae: Implications for theropod systematics".

8626:

von Huene, Friedrich (1926). "The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe".

2300:, a specialist on the Morrison Formation, suggests that 1 metric ton (1.1 short tons) is reasonable for large adults of 10795: 9602: 7722: 7097: 2281: 1366:(cheekbone) with a straight lower margin. Fossils are confined to the Salt Wash Member of the Morrison Formation, with 1082:. Under a cooperative effort involving nearly 40 institutions, thousands of bones were recovered between 1960 and 7024: 4321:

The Morrison Formation has been a rich fossil hunting ground. The flora of the period has been revealed by fossils of

15235: 10110: 9965: 9909:"Carnosaurs as Apex Scavengers: Agent-based simulations reveal possible vulture analogues in late Jurassic Dinosaurs" 8537: 6837:

Marsh, 1877 (Dinosauria, Theropoda): proposed conservation of usage by designation of a neotype for its type species

1530: 835: 569: 10833: 8532:

Martin, A.J. (2006). Introduction to the Study of Dinosaurs. Second Edition. Oxford, Blackwell Publishing. 560 pp.

6104: 5311:"Osteology of the carnivorous dinosauria in the United States National Museum, with special reference to the genera 3952:

indicates that the skull was held nearly horizontal, as opposed to strongly tipped up or down. The structure of the

3756:

was able to "move its head and neck around relatively rapidly and with considerable control", at the cost of power.

15240: 6483:"Osteology of a large allosauroid theropod from the Upper Jurassic (Tithonian) Morrison Formation of Colorado, USA" 5981:(Theropoda: Carnosauria) in the Upper Jurassic of Portugal: First evidence of an intercontinental dinosaur species" 5310: 1219:

bones included five ribs, five vertebrae, and four bones of the feet. Several of its damaged bones showed signs of

1132:

The period since Madsen's monograph has been marked by a great expansion in studies dealing with topics concerning

131: 13691: 10034:"New information on paleopathologies in non-avian theropod dinosaurs: a case study on South American abelisaurids" 12225: 8557:

on 310 and 311 as well; Madsen (1976) interpreted these bones as possible upper portions of the inner metatarsal.

7231:"On certain genera and species of carnivorous dinosaurs, with special reference to Ceratosaurus nasicornis Marsh" 6168: 5498: 4061: 3886: 3695:

later. An additional suggestion notes that ornithopods were the most common available dinosaurian prey, and that

3498: 2623: 2382: 1059: 654: 12211: 9190:

Loewen, Mark A. (2002). "Ontogenetic changes in hindlimb musculature and function in the Late Jurassic theropod

6188: 14473: 10212:

Roach, Brian T.; Brinkman, Daniel L. (2007). "A reevaluation of cooperative pack hunting and gregariousness in

8197:"How big was 'Big Al'? Quantifying the effect of soft tissue and osteological unknowns on mass predictions for 5132:

The Illustrated Encyclopedia of Dinosaurs: An Original and Compelling Insight into Life in the Dinosaur Kingdom

4627:

was more compact, with longer legs, faster but less maneuverable, and seems to have preferred dry floodplains.

3450: 3346:, but this has been rejected, with tyrannosaurids identified as members of a separate branch of theropods, the 1763:

because Bakker's action was predicated upon the false assumption of USNM 4734 being distinct from long-snouted

1227:. The infection was long-lived, perhaps up to six months. "Big Al II" is also known to have multiple injuries. 15225: 10229: 8086:"Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions" 6308:

Galton, Peter M.; Carpenter, Kenneth; Dalman, Sebastian G. (2015). "The holotype pes of the Morrison dinosaur

4064:. Another specimen had fractured ribs and fused vertebrae near the end of the tail. An apparent subadult male 3445: 2626:, independent of size, the pubes had not fused to each other at their foot ends. He suggested that this was a 15245: 14914: 12204: 11400: 10126:

Farlow, James O. (1976). "Speculations about the diet and foraging behavior of large carnivorous dinosaurs".

9661: 6510: 2304:, but that 700 kg (1,500 lb) is a closer estimate for individuals represented by the average-sized 2206: 942:

and several partial skeletons. In addition, one of Cope's collectors, H. F. Hubbell, found a specimen in the

13709: 11406: 10672:

Drumheller, Stephanie K.; McHugh, Julia B.; Kane, Miriam; Riedel, Anja; D’Amore, Domenic C. (May 27, 2020).

8842: 2231:, noted that the bone closely resembled that of their new genus. This specimen is sometimes referred to as " 2205:

in Early Cretaceous beds in southeastern Australia. It was thought to provide evidence that Australia was a

1905:, another Marsh name, was given to a partial skeleton in 1878. He later decided it warranted its own genus, 15220: 14487: 10428:

Molnar, R.E. (2001). "Theropod paleopathology: a literature survey". In Tanke, D.H.; Carpenter, K. (eds.).

5501:, Upper Jurassic Morrison Formation, Utah: a re-evaluation". In Foster, John R.; Lucas, Spencer G. (eds.). 2579: 2297: 786: 683:, a type of carnosaurian theropod dinosaur. As the most abundant large predator of the Morrison Formation, 12910: 10443:

Xing, Lida; Rothschild, Bruce M.; Du, Chunlei; Wang, Donghao; Wen, Kexiang; Su, Jiayin (January 2, 2024).

8699:

Steel, R. (1970). "Part 14. Saurischia. Handbuch der Paläoherpetologie/Encyclopedia of Paleoherpetology".

8407:

Chure, Daniel J.; Madsen, James (1996). "On the presence of furculae in some non-maniraptoran theropods".

5425:"Skull and tooth morphology as indicators of niche partitioning in sympatric Morrison Formation theropods" 1984:, based on a scrap of vertebra Marsh first thought to be a mammalian jaw, has been listed as a synonym of 1929:, and might represent a different genus. However, they found that the specimen was undiagnostic, and thus 1925:. Paul and Carpenter stated that the type specimen of this species, YPM 1931, was from a younger age than 801:, who identified it as half of a tail vertebra and tentatively assigned it to the European dinosaur genus 10747: 7625:

Janensch, Werner (1925). "Die Coelurosaurier und Theropoden der Tendaguru-Schichten Deutsch-Ostafrikas".

1607:, or that were misassigned to the genus, are obscure and based on very scrappy remains. One exception is 595: 12218: 4723:, a new species from the lower part of the Morrison Formation (Upper Jurassic) of Western North America" 2320:

has been measured up to 7 m (23 ft) in length and 1 metric ton (1.1 short tons) in body mass.

1027:

was based on material with poor, if any, diagnostic features and locality information. For example, the

15215: 14480: 3501:. Today, this bone tissue is only formed in female birds that are laying eggs, as it is used to supply 2479:, and varied in shape and size. There were also lower paired ridges running along the top edges of the 2398: 778: 143: 13716: 9982: 9908: 9603:"Allosaurus, crocodiles, and birds: Evolutionary clues from spiral computed tomography of an endocast" 7062: 5947:

from the Morrison Formation (Upper Jurassic) of Oklahoma, USA". In Ailing Sun; Yuangqing Wang (eds.).

15048: 10444: 5685:

Foster, John R.; Chure, Daniel J. (2006). "Hindlimb allometry in the Late Jurassic theropod dinosaur

1968:

Greppin, 1870, based on a tooth from the Late Jurassic of Switzerland. However, a recent overview of

8353:(1977). "Analogies in the evolution of combat and display structures in ornithopods and ungulates". 3960:

was more adapted to hear lower frequencies and would have had difficulty hearing subtle sounds. The

3898:. The same interpretation applies to Bakker's lair sites. There is some evidence for cannibalism in 3759: 3617:

the 1990s and the first decade of the 21st century may have found other solutions to this question.

2456:(the bones that formed the tip of the snout) held five teeth with D-shaped cross-sections, and each 1108:

describing bones usually found fused. Due to being one of Utah's two fossil quarries where numerous

797:

rocks. The locals had identified such bones as "petrified horse hoofs". Hayden sent his specimen to

15270: 10951: 7646:"Post-cranial remains of 'coelurosaurs' (Dinosauria, Theropoda) from the Late Jurassic of Tanzania" 7439:

Greppin, J.B. (1870). "Description geologique du Jura bernois et de quelques districts adjacents".

2390: 1204:, "Big Al II". This specimen, the best preserved skeleton of its kind to date, is also referred to 976: 950:, but apparently did not mention its completeness and Cope never unpacked it. Upon unpacking it in 10100: 9955: 8466: 5689:, with comments on its abundance and distribution". In Foster, John R.; Lucas, Spencer G. (eds.). 5497:

Hunt, Adrian P; Lucas, Spencer G.; Krainer, Karl; Spielmann, Justin (2006). "The taphonomy of the

2861:

relationships, none of these theropods is now recognized as an allosaurid, although several, like

1706:

in a figure caption for the partial skull YPM 1893 and YPM 1893 has been treated as a specimen of

579: 15260: 15042: 13697: 10856: 9529: 9469: 9176: 8498: 7457:

Olshevsky, 1978. The archosaurian taxa (excluding the Crocodylia). Mesozoic Meanderings. 1, 1–50.

4851:

Leidy, Joseph (1873). "Contribution to the extinct vertebrate fauna of the western territories".

3663: 2775:

during the same period, is a point that needs to be remembered when searching for information on

2202: 1632: 923: 8496:

Carpenter, Kenneth (2002). "Forelimb biomechanics of nonavian theropod dinosaurs in predation".

7268: 6624: 6618: 6515:(Theropoda: Carnosauria) del yacimiento de Andrés (Jurásico Superior; centro-oeste de Portugal)" 6043:

Chure, Daniel J. (2000). "Observations on the morphology and pathology of the gastral basket of

5162: 5156: 2272:, having a massive skull on a short neck, a long, slightly sloping tail, and reduced forelimbs. 896: 608:) ("lizard" or "reptile"). The first fossil remains that could definitively be ascribed to this 15172: 15068: 10321:"Reconstructing the behaviors of extinct species: An excursion into comparative paleoneurology" 9556:"Reconstructing the behaviors of extinct species: An excursion into comparative paleoneurology" 8008: 7530: 2575: 2308:

he has measured. Using the subadult specimen nicknamed "Big Al", since assigned to the species

10630:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 223–231. 10580:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 233–248. 10561:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 131–138. 8814: 8806: 7508: 6403:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 123–129. 6253:

Foth, C.; Evers, S.; Pabst, B.; Mateus, O.; Flisch, A.; Patthey, M.; Rauhut, O. W. M. (2015).

5916: 5904: 5697:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 119–122. 2652:. The arms were powerful, and the forearm was somewhat shorter than the upper arm (1:1.2 2574:

supporting the hips. The number of tail vertebrae is unknown and varied with individual size;

15167: 15159: 13422: 13334: 8781: 8773: 8239:"Big boned: How fat storage and other adaptations influenced large theropod foraging ecology" 7770: 7764: 6682: 6674: 6648: 5186:

Breithaupt, Brent H. (1999). "AMNH 5753: The world's first free-standing theropod skeleton".

3735: 3327: 2788: 2756: 2508: 1181: 1169: 1158: 892: 840: 620: 10762: 9011: 8672: 8194: 6521:(Theropoda: Carnosauria) of the Andrés deposit (Upper Jurassic; central-west Portugal)] 5562: 5509:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. pp. 57–65. 3964:

were large and well suited for detecting odors, but were typical for an animal of its size.

2676:-like than those of earlier theropods. Each foot had three weight-bearing toes and an inner 1495: 1453: 1188:

team. This skeleton was discovered by a Swiss team, led by Kirby Siber. Chure and Loewen in

644: 15115: 15106: 15000: 13111: 13079: 10685: 10458: 10320: 10045: 9998: 9920: 9776: 9555: 9425: 9376: 9321: 9070: 8921: 8857: 8727: 8416: 8250: 8097: 8023: 7961: 7922: 7803: 7657: 7550: 7405: 7306: 7140: 6932: 6756: 6173:) with comparisons to allosaur pathology in the Cleveland-Lloyd Dinosaur Quarry Collection" 5995: 5809:, crocodiles, and birds: Evolutionary clues from spiral computed tomography of an endocast" 5724: 5606: 5455: 5265: 5000: 4919: 3581:

as an active predator of large animals. There is dramatic evidence for allosaur attacks on

3429: 3420: 3412: 2889: 1944: 1768: 1740: 1711: 1695: 1691: 1676: 1664: 1640: 1612: 1554: 1467: 1197: 1189: 1165: 1121: 1083: 1079: 1075: 1067: 1028: 996: 980: 955: 951: 947: 935: 782: 613: 477: 467: 454: 427: 415: 400: 361: 341: 324: 271: 249: 14467: 10590: 9045: 7691:

Rauhut, Oliver W. M. "Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)".

5522: 2433: 2034:, and a metatarsal. Following Paul's work, this species has been accepted as a synonym of 1487: 1047: 991:. The most influential early attempt to sort out the convoluted situation was produced by 568:" means "different lizard", alluding to its unique (at the time of its discovery) concave 8: 15195: 13435: 13222: 9719: 6453: 4164:

of caudals", possibly due to physical trauma, as well as the fusion of chevrons to centra

4090: 3881:

feeding sites. According to this interpretation, the accumulation of remains of multiple

3708:

could open its jaws quite wide and sustain considerable muscle force. When compared with

3485:

Medullary bone tissue (endosteally derived, ephemeral, mineralization located inside the

3184: 2784: 2153: 900: 561: 550: 441: 13704: 10689: 10507:. Albuquerque, New Mexico: New Mexico Museum of Natural History and Science. p. 29. 10462: 10076: 10049: 10033: 10032:

Baiano, Mattia A.; Cerda, Ignacio A.; Bertozzo, Filippo; Pol, Diego (January 31, 2024).

10002: 9924: 9884: 9849: 9780: 9429: 9380: 9325: 9074: 8925: 8861: 8731: 8572: 8420: 8281: 8254: 8238: 8101: 8027: 7965: 7926: 7807: 7661: 7554: 7409: 7310: 7144: 6936: 6760: 5999: 5728: 5610: 5459: 5269: 5004: 4923: 4772: 4580: 14907: 13411: 13271: 13127: 13067: 12502: 12412: 12295: 11159: 10849: 10716: 10673: 10449: 10392: 10367: 10272: 10233: 10143: 10102:

Jurassic West, Second Addition: The Dinosaurs of the Morrison Formation and Their World

9957:

Jurassic West, Second Addition: The Dinosaurs of the Morrison Formation and Their World

9673: 9446: 9413: 9394: 9345: 9289: 9260: 9212: 9150: 9093: 9058: 8997: 8964: 8945: 8937: 8881: 8751: 8743: 8608: 8515: 8039: 7984: 7949: 7673: 7421: 7396:

Carrano, Benson; Sampson (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)".

7322: 7156: 7129:"Notice of a new genus of Sauropoda and other new dinosaurs from the Potomac Formation" 6948: 6863: 6808: 6614: 6587: 6548: 6285: 6254: 6235: 6200: 6011: 5748: 5664: 5544: 5479: 5306: 5230: 5068: 5016: 4935: 4749: 4718: 4537:

is present are interpreted as having been similar to the Morrison, but with a stronger

4310: 4247: 4024: 3997:

behavioral significance since while injuries to the feet could be caused by running or

2780: 2587: 2210: 1896: 1779: 1176:

was discovered, measuring about 8 metres (26 ft) long. MOR 693 was excavated near

1071: 1063: 1016: 992: 794: 671:

predator for its time. Its skull was light, robust, and equipped with dozens of sharp,

640: 624: 371: 138: 9490: 8196: 7947: 7907: 6508: 6019: 3690:

and lessen stress. Another possibility for handling large prey is that theropods like

2356:, though recent studies support it as a separate genus. Another potential specimen of 15154: 14789: 14706: 14680: 14519: 14506: 14384: 13925: 13877: 12709: 12059: 11138: 10721: 10703: 10654: 10546: 10526: 10474: 10397: 10348: 10340: 10299: 10276: 10192: 10106: 10081: 10063: 10014: 9961: 9936: 9889: 9871: 9830: 9700: 9665: 9630: 9622: 9583: 9575: 9451: 9337: 9312:

Frazzetta, T. H.; Kardong, K. V. (2002). "Prey attack by a large theropod dinosaur".

9294: 9226: 9142: 9098: 9002: 8984: 8949: 8873: 8818: 8785: 8679: 8650: 8612: 8600: 8592: 8533: 8286: 8268: 8177: 8167: 8043: 7989: 7774: 7677: 7488: 7371: 7326: 7160: 6952: 6901: 6696: 6686: 6628: 6592: 6574: 6461: 6290: 6239: 6192: 6086: 6056: 6015: 5952: 5920: 5856: 5830: 5782: 5740: 5656: 5548: 5471: 5424: 5166: 5135: 5072: 5020: 4939: 4883: 4873: 4754: 4422: 3949: 3777:

Other aspects of feeding include the eyes, arms, and legs. The shape of the skull of

3528: 2764: 2627: 2590:. The rib cage was broad, giving it a barrel chest, especially in comparison to less 2528: 2406: 2293: 1836: 1656: 1550: 1479: 979:

suggested that too many names had been coined. For example, Williston pointed out in

969: 755: 10237: 10010: 9932: 9677: 9154: 8885: 8755: 8519: 7425: 7246: 7230: 6867: 6832: 6812: 6204: 5770: 5668: 5483: 5345: 2857:. Given modern knowledge of theropod diversity and the advent of cladistic study of 2610:

poorly. In one published case, the gastralia show evidence of injury during life. A

1503: 14893: 14650: 14560: 14349: 14265: 14127: 14046: 14018: 13978: 13859: 13829: 13347: 13100: 12964: 12821: 12721: 12570: 12477: 12435: 12002: 11312: 10711: 10693: 10600: 10571: 10466: 10387: 10379: 10332: 10268: 10264: 10225: 10135: 10071: 10053: 10006: 9928: 9879: 9861: 9822: 9784: 9738: 9657: 9614: 9567: 9508: 9441: 9433: 9398: 9384: 9365:"Prey attack by a large theropod dinosaur: Response to Frazzetta and Kardong, 2002" 9349: 9329: 9284: 9276: 9132: 9088: 9078: 9036: 8992: 8976: 8929: 8865: 8735: 8584: 8507: 8458: 8428: 8424: 8330: 8276: 8258: 8115: 8105: 8031: 7979: 7969: 7930: 7892: 7888: 7811: 7665: 7571: 7566: 7558: 7413: 7314: 7250: 7242: 7209: 7201: 7148: 6940: 6893: 6855: 6800: 6768: 6764: 6582: 6564: 6329: 6280: 6270: 6227: 6184: 6003: 5853:

Dinofest International, Proceedings of a Symposium Held at Arizona State University

5820: 5752: 5732: 5648: 5618: 5614: 5540: 5536: 5496: 5467: 5463: 5341: 5333: 5273: 5222: 5199: 5195: 5102: 5063: 5058: 5050: 5008: 4927: 4744: 4734: 4612: 4382: 3998: 3989: 3985: 3937: 3782: 3648: 3618: 3424: 3105: 2829: 2823: 2811: 2744: 2532: 2209:

for animals that had gone extinct elsewhere. This identification was challenged by

1873: 1867:. The referral was not accepted in the most recent review of basal tetanurans, and 1833: 1756: 1651:

had tall pointed horns and a slender build compared to a postulated second species

790: 497: 10470: 4639:

in functional anatomy by having a taller, narrower skull with large, broad teeth.

14956: 14694: 14657: 14589: 14444: 14437: 14249: 14191: 14164: 14154: 14113: 13948: 13807: 13791: 13609: 13581: 13559: 13446: 13291: 12998: 12772: 12655: 12633: 12554: 12383: 12360: 12353: 12331: 12317: 12310: 12271: 12122: 11969: 11896: 11885: 11821: 11709: 11596: 11173: 11082: 10936: 10911: 10799: 10772: 10698: 8335: 8318: 8263: 7974: 7950:"New Mid-Cretaceous (Latest Albian) Dinosaurs from Winton, Queensland, Australia" 7417: 6787:

Carpenter, Kenneth (2010). "Variation in a population of Theropoda (Dinosauria):

5635:

Bybee, Paul J.; Lee, AH; Lamm, ET (2006). "Sizing the Jurassic theropod dinosaur

5127: 4777: 4488: 4366: 4044:

provide evidence for "very active" predation-based rather than scavenging diets.

3335: 2853: 2835: 2701: 2685: 2504: 2489: 2449: 2425:

was also sexually dimorphic in the width of the femur's head against its length.

2394: 2323: 2237: 2145: 2007: 1871:

was simply listed as a dubious species of theropod. It may be closely related to

1546: 1145:

very complete new specimens have also contributed to the growing knowledge base.

704: 8006: 7349:

Trudy Geologichyeskago Muszeyah imeni Petra Velikago Imperatorskoy Academiy Nauk

6509:

Malafaia, Elisabete; Dantas, Pedro; Ortega, Francisco; Escaso, Fernando (2007).

6333: 4958: 3549:

forward progression. Conversely, the skull bones appear to have generally grown

1759:

as "Madsenius trux". However, "Madsenius" is now seen as yet another synonym of

1286:. Among these, Daniel Chure and Mark Loewen in 2020 only recognized the species 14921: 14884: 14865: 14827: 14816: 14613: 14326: 14285: 14276: 14258: 14238: 14134: 13848: 13593: 13455: 13282: 13264: 13092: 13059: 13045: 13006: 12780: 12641: 12598: 12591: 12513: 12489: 12442: 12401: 12338: 12324: 12052: 12037: 11864: 11698: 11562: 11530: 11519: 11496: 11458: 11319: 11289: 11213: 11152: 11051: 10368:"Olfactory acuity in theropods: Palaeobiological and evolutionary implications" 10058: 9788: 9063:

Proceedings of the National Academy of Sciences of the United States of America

8980: 6804: 4797: 4792: 4611:

in both the United States and Portugal. The three appear to have had different

4354: 4283: 4150: 4133: 3972: 3961: 3652: 3323: 3208: 2817: 2760: 2524: 2475:

above and in front of the eyes. These horns were composed of extensions of the

2472: 2214: 2102: 1522: 1396: 1316: 1235: 1216: 1177: 803: 617: 10604: 9826: 9815:

Earth and Environmental Science Transactions of the Royal Society of Edinburgh

9245:

Fastovsky, David E.; and Smith, Joshua B. (2004). "Dinosaur Paleoecology", in

8933: 8869: 8035: 7815: 7669: 7016: 6944: 6547:

Evers, Serjoscha W.; Foth, Christian; Rauhut, Oliver W.M. (February 7, 2020).

5337: 3984:

In 2001, Bruce Rothschild and others published a study examining evidence for

15189: 14963: 14809: 14770: 14749: 14628: 14621: 14548: 14342: 14315: 14173: 14089: 14067: 14060: 14053: 13996: 13913: 13776: 13748: 13735: 13659: 13536: 13376: 13210: 13141: 13027: 13014: 12759: 12737: 12730: 12694: 12667: 12619: 12543: 12279: 12070: 12044: 11960: 11941: 11934: 11871: 11850: 11829: 11814: 11800: 11759: 11725: 11718: 11637: 11489: 11376: 11369: 11296: 11266: 11255: 11145: 11116: 11109: 11035: 10817: 10707: 10658: 10478: 10344: 10067: 10018: 9940: 9875: 9834: 9764: 9742: 9704: 9669: 9626: 9579: 8988: 8596: 8272: 7318: 7152: 6905: 6578: 6196: 6060: 6007: 5786: 5277: 5012: 4931: 4686:

material suggest scavenging, either from the other theropods or from another

4440: 4434: 4407: 4401: 4386: 4298: 4251: 4250:, accounting for 70 to 75% of theropod specimens, and as such was at the top 4243: 4184: 4139: 4123: 4112: 4096: 4012: 4001:, resistant prey items are the most probable source of injuries to the hand. 3895: 3740: 3671: 3513:

individual. Data from extant birds suggested that the medullary bone in this

3474: 3408: 3380: 3355: 3347: 3331: 2925: 2912: 2878: 2847: 2669: 2633: 2476: 2340: 2253: 2157: 2089: 2016: 1475: 1220: 852: 573: 547: 463: 352: 245: 76: 30: 10788: 10298:. Bloomington and Indianapolis: Indiana University Press. pp. 301–342. 9491:

Snively, Eric.; Cotton, John R.; Ridgely, Ryan; Witmer, Lawrence M. (2013).

9225:. Bloomington and Indianapolis: Indiana University Press. pp. 325–350. 9083: 8181: 8144:. Albuquerque: New Mexico Museum of Natural History and Science. p. 37. 8110: 8085: 7908:"A new carnosaur (Dinosauria: Theropoda) from the Lower Cretaceous of Japan" 7718: 7370:(1st ed.). Berkeley: University of California Press. pp. 169–209. 7347:

Riabinin, Anatoly Nikolaenvich (1914). "Zamtka o dinozavry ise Zabaykalya".

7193: 7105: 6700: 6482: 6259:(Dinosauria: Theropoda) based on another specimen with multiple pathologies" 6231: 6090: 5771:"Brontosaur killers: Late Jurassic allosaurids as sabre-tooth cat analogues" 5639:: Assessing growth strategy and evolution of ontogenetic scaling of limbs". 5054: 4887: 4867: 3640: 3489:

of the long bones in gravid female birds) has been reported in at least one

15091: 14935: 14873: 14843: 14763: 14756: 14734: 14726: 14606: 14598: 14578: 14293: 14204: 14142: 14032: 14003: 13955: 13784: 13769: 13544: 13476: 13404: 13383: 13362: 13178: 13134: 12942: 12929: 12859: 12812: 12687: 12577: 12529: 12522: 12459: 12428: 12421: 12302: 12129: 11981: 11878: 11780: 11773: 11668: 11652: 11588: 11539: 11471: 11248: 11131: 11124: 11095: 11058: 11027: 10725: 10549:(2006). "Biggest of the big: a critical re-evaluation of the mega-sauropod 10518: 10401: 10383: 10352: 10161: 10085: 9893: 9634: 9587: 9455: 9341: 9298: 9280: 9146: 9102: 9059:"Sexual maturity in growing dinosaurs does not fit reptilian growth models" 9006: 8877: 8739: 8604: 8462: 8350: 8290: 7993: 7851: 7793: 6596: 6460:(2nd ed.). Berkeley: University of California Press. pp. 71–110. 6294: 5834: 5744: 5660: 5475: 4758: 4652: 4647: 4643:

was itself a potential food item to other carnivores, as illustrated by an

4601: 4497: 4493: 4482: 4458: 4428: 4395: 4390: 4362: 4210:

Exostosis in a pedal phalanx possibly attributable to an infectious disease

4074: 4018: 3727: 3714: 3479: 3403:. In 2019, Rauhut and Pol noted that the definitive taxonomic placement of 3322:

Allosauridae is one of four families in Allosauroidea; the other three are

3160: 2841: 2792: 2752: 2661: 2619: 2615: 2607: 2591: 2541: 2519: 2513: 2130: 2111: 2024:

was originally coined by Cope in 1878 as the type species of his new genus

1963: 1859: 1672: 1416: 1389: 1336: 1309: 1272: 1141: 1137: 1117: 1086:, led by James Henry Madsen. The quarry is notable for the predominance of 798: 554: 540: 396: 279: 227: 34: 10445:"New palaeopathology cases of Allosaurus fragilis (Dinosauria: Theropoda)" 9619:

10.1002/(SICI)1097-0185(19991015)257:5<162::AID-AR5>3.0.CO;2-W

7852:

Molnar, Ralph E.; Flannery, Timothy F.; Rich, Thomas H.V. (1985). "Aussie

6897: 6859: 5949:

Sixth Symposium on Mesozoic Terrestrial Ecosystems and Biota, Short Papers

5826:

10.1002/(SICI)1097-0185(19991015)257:5<162::AID-AR5>3.0.CO;2-W

1015:

became the accepted name for this familiar genus for over 50 years, until

1011:

should be the preferred name because, as the older name, it had priority.

15141: 15100: 14989: 14970: 14900: 14850: 14836: 14778: 14719: 14664: 14541: 14335: 14211: 14180: 14096: 14082: 13814: 13762: 13630: 13552: 13515: 13397: 13369: 13322: 13242: 13120: 12977: 12828: 12801: 12701: 12648: 12584: 12563: 12536: 12287: 12100: 12093: 12079: 11905: 11752: 11743: 11645: 11616: 11546: 11511: 11504: 11304: 11282: 11275: 11234: 11226: 11202: 11187: 11166: 11074: 11066: 10336: 9571: 9040: 6108: 4658: 4607: 4509: 4476: 4452: 4413: 4322: 4205: 4149:

Distortions of the joint surfaces of the tail vertebrae, possibly due to

3486: 3129: 3081: 3015: 2748: 2665: 2583: 2227: 2222: 2186: 1720: 960: 737: 692: 51: 10828: 10166:"Head-biting behavior in theropod dinosaurs: Paleopathological evidence" 9866: 9850:"Bite and tooth marks on sauropod dinosaurs from the Morrison Formation" 9437: 7743: 7562: 1491: 15133: 14928: 14857: 14802: 14423: 14222: 14039: 14025: 14010: 13962: 13896: 13822: 13644: 13637: 13623: 13529: 13462: 13390: 13354: 13307: 13249: 13235: 13202: 13194: 13168: 12991: 12956: 12744: 12345: 12136: 12086: 12023: 11994: 11949: 11927: 11920: 11912: 11836: 11732: 11691: 11684: 11676: 11660: 11580: 11451: 11327: 11180: 11043: 10902: 10147: 9724:(Dinosauria; Theropoda): An interpretation of cranio-dental morphology" 8941: 8747: 8511: 8119: 7645: 7590:

und die Megalosaurier aus den Tendaguru-Schichten Deutsch-Ostafricas".

7254: 6569: 6389: 5652: 5234: 4739: 4503: 4470: 4464: 4358: 4267: 4263: 4259: 4254:

of the Morrison food chain. The Morrison Formation is interpreted as a

4228: 4197: 4193: 4170: 4157: 4079: 3941: 3786: 3593: 3545: 3230: 3032: 2984: 2805: 2681: 2603: 2500: 2480: 2453: 2402: 2386: 2367: 2362: 2235:", an informal museum name. It likely belonged to something similar to 2194: 2026: 1849: 1844: 1811: 1775: 1408: 1328: 1224: 943: 688: 680: 649: 434: 389: 201: 118: 96: 61: 15146: 9414:"Estimating cranial musculoskeletal constraints in theropod dinosaurs" 8588: 8305:

Jurassic West: the Dinosaurs of the Morrison Formation and Their World

8164:

Jurassic West: The Dinosaurs of the Morrison Formation and Their World

8007:

Agnolin, F. L.; Ezcurra, M. D.; Pais, D. F.; Salisbury, S. W. (2010).

7214: 7194:"Bibliography and catalogue of the fossil vertebrata of North America" 6452: 6275: 5974: 3190: 2448:

were modestly proportioned for a theropod of its size. Paleontologist

2172:

sp. (meaning the authors found the specimens to be most like those of

2038:. A 2010 study by Paul and Kenneth Carpenter, however, indicates that 1710:. Likewise, "Labrosaurus fragilis" is a typographical error by Marsh ( 14949: 14942: 14642: 14635: 14308: 14300: 14231: 13884: 13602: 13148: 13052: 12787: 12372: 12257: 12244: 12171: 12107: 12030: 12009: 11766: 11629: 11437: 11424: 11342: 11194: 11013: 11000: 10963: 10872: 9137: 9120: 7365: 7177:

Lull, Richard Swann (1911). "The Reptilia of the Arundel Formation".

6085:. Casper, Wyoming: Wyoming Geological Association. pp. 309–313. 5736: 4563: 4446: 4378: 4370: 4330: 4292: 4275: 4222: 4177: 4161: 4070: 4032: 3953: 3945: 3609: 3550: 3469: 3415:

or Allosauria, or even as a basalmost carcharodontosaurian. In 2024,

3339: 2953: 2858: 2706: 2552: 2537: 2285: 2242: 2168:

Kurzanov and colleagues in 2003 designated six teeth from Siberia as

2075:

There are also several species left over from the synonymizations of

2030:, and is based on what is now AMNH 5767, parts of three vertebrae, a 1743:, being based on remains from Dinosaur National Monument assigned to 1617: 1393: 1313: 1103:

Regardless of the actual cause, the great quantity of well-preserved

1099: 965: 770: 558: 543: 214: 155: 101: 45: 38: 15062: 10642: 10296:

Feathered Dragons: Studies on the Transition from Dinosaurs to Birds

10139: 9389: 9364: 9333: 8166:. Bloomington, Indiana: Indiana University Press. pp. 170–176. 8084:

Campione, N. E.; Evans, D. C.; Brown, C. M.; Carrano, M. T. (2014).

7934: 7128: 6920: 5249: 5226: 5154: 4988: 4907: 3569:

plate close-up, showing how well the damage matches the front of an

3561: 3350:. Allosauridae is the smallest of the carnosaur families, with only 3213: 2338:, but may in fact belong to other genera. The closely related genus 2010:

for giant Morrison allosaur remains, and included in his conception

1565:

officially transferred to the more complete specimen USNM4734 (as a

1153: 15085: 14533: 13941: 13934: 13906: 13799: 13299: 12680: 12016: 11843: 11604: 11241: 10920: 10896: 10805: 10165: 9648:

Stevens, Kent A. (2006). "Binocular vision in theropod dinosaurs".

7487:. Jefferson, North Carolina: McFarland & Co. pp. 105–117. 6743:

Smith, David K. (1999). "Patterns of size-related variation within

5107: 5090: 4573: 4418: 4305: 4255: 4188: 4029: 3993: 3918: 3626: 3605: 2721: 2606:(belly ribs), but these are not common findings, and they may have 2567: 2465: 2269: 2119:, named by Marsh in 1896 for a Morrison theropod tooth, which like 2031: 1980: 1840: 1783: 1627: 1412: 1400: 1332: 1320: 832: 696: 672: 407: 188: 175: 91: 86: 71: 66: 56: 9809:

Storrs, Glenn W.; Oser, Sara E.; Aull, Mark (September 23, 2013).

7611:

Tykoski, Ronald S.; and Rowe, Timothy. (2004). "Ceratosauria", in

6549:"Notes on the cheek region of the Late Jurassic theropod dinosaur 5943:

Chure, Daniel J. (1995). "A reassessment of the gigantic theropod

5446:

Stokes, William L. (1945). "A new quarry for Jurassic dinosaurs".

4100:

Skeletal restoration of "Big Al II" showing bones with pathologies

3730:

study published in 2013 by Eric Snively and colleagues found that

2221:, but could represent an allosauroid. Similarly, Yoichi Azuma and 2072:. This reassignment was rejected in a review of basal tetanurans. 1647:, the freelance artist & author Gregory S. Paul proposed that 1569:), a decision that was ratified by the ICZN on December 29, 2023. 1521:

The issue of species and potential synonyms is complicated by the

1506:

and colleagues. The species appeared earlier in the Jurassic than

725: 14074: 13836: 13566: 13469: 12794: 12115: 10624: