University of Western Australia Library. Unlike predators such as Ceratosaurus and Torvosaurus who lived alongside allozaurus, Allosaurus had powerful arms with large hands and big claws. Measuring feet meters long, Allosaurus was the most common carnivorous dinosaur in Morrison Formation ecosystems. Utah — Emery County. These adaptations would have allowed it to use its arms in attacking prey.
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Description: Forty-nine years have elapsed since the initial collection of dinosaur remains by professional paleontologists from the Cleveland-Lloyd Dinosaur Quarry, during which time little descriptive work has been published on this extraordinary site. A massive accumulation of dinosaur bones pertaining to at least eleven genera, and possibly more, lie within the Brushy Basin Member of the Late Jurassic Morrison Formation. Allosaurus fragilis, the most common taxon, is represented by bones from many individuals of different size.
Bones from the Cleveland-Lloyd Dinosaur Quarry are extremely well preserved but from almost completely disarticulated skeletons. Sixty or more individuals are indicated by more than ten thousand elements. Practically every bone of the skeleton of Allosaurus fragilis from juvenile to adult has been recovered since the first organized excavation in Growth stages of this species represent individuals ranging from one to four and one-half meters in height and from three to twelve meters in length.
The disassociation of skeletal material is an advantage in illustrating and describing contacts and sutures between those bones normally found together or coossified. The variety, preservation, and great number of bones may never be as well represented for any other theropod genus. Although descriptions and illustrations are often of composite bones, they are based on numerous elements. The material is also more than adequate for studies of growth, individual variation, and abnormality.
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The snout of Allosaurus was narrower than the back part of the skull, which was stoutly built for predation. The back part of the skull was also dropped down relative to the snout, allowing Allosaurus to have more teeth in contact with its prey when it snapped its jaws shut. Allosaurus had short crest-like horns in front of its eyes, which were possibly used to attract mates or recognize other members of its species. Although probably not a fast runner, we know from proportions of its hind limbs and reconstructions of the muscles that moved these limbs that Allosaurus was likely faster than other contemporaneous meat eaters and certainly faster than anything it preyed upon.
Allosaurus: A Revised Osteology PDF
Description[ edit ] The size range of Allosaurus compared with a human. Allosaurus was a typical large theropod , having a massive skull on a short neck , a long, slightly sloping tail and reduced forelimbs. Allosaurus fragilis, the best-known species, had an average length of 8. Paleontologist Gregory S. Each dentary the tooth-bearing bone of the lower jaw had between 14 and 17 teeth, with an average count of The teeth became shorter, narrower, and more curved toward the back of the skull.