Post by Ausar the Vile on Jun 15, 2014 17:05:39 GMT -7
Allosaurus fragilis
Allosaurus /ˌælɵˈsɔrəs/ is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period (Kimmeridgian to early Tithonian). The name "Allosaurus" means "different lizard". It is derived from the Greek ἄλλος/allos ("different, other") and σαῦρος/sauros ("lizard / generic reptile"). The first fossil remains that can definitely be ascribed to this genus were described in 1877 by paleontologist Othniel Charles Marsh, and it became known as Antrodemus. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. Indeed, it has been a top feature in several films and documentaries about prehistoric life. Allosaurus was a large bipedal predator. Its skull was large and equipped with dozens of large, sharp teeth. It averaged 8.5 m (28 ft) in length, though fragmentary remains suggest it could have reached over 12 m (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long and heavily muscled tail. It is classified as an allosaurid, a type of carnosaurian theropod dinosaur. The genus has a complicated taxonomy, and includes an uncertain number of valid species, the best known of which is A. fragilis. The bulk of Allosaurus remains have come from North America's Morrison Formation, with material also known from Portugal and possibly Tanzania. It was known for over half of the 20th century as Antrodemus, but study of the copious remains from the Cleveland-Lloyd Dinosaur Quarry brought the name "Allosaurus" back to prominence, and established it as one of the best-known dinosaurs. As the most abundant large predator in the Morrison Formation, Allosaurus was at the top of the food chain, probably preying on contemporaneous large herbivorous dinosaurs and perhaps even other predators. Potential prey included ornithopods, stegosaurids, and sauropods. Some paleontologists interpret Allosaurus as having had cooperative social behavior, 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. It may have attacked large prey by ambush, using its upper jaw like a hatchet.
Ceratosaurus spp.
Ceratosaurus /ˌsɛrətɵˈsɔrəs/ meaning "horned lizard", in reference to the horn on its nose (Greek κερας/κερατος, keras/keratos meaning "horn" and σαυρος/sauros meaning "lizard"), was a large predatory theropod dinosaur from the Late Jurassic Period (Kimmeridgian to Tithonian), found in the Morrison Formation of North America, and the Lourinhã Formation of Portugal. It was characterized by large jaws with blade-like teeth, a large, blade-like horn on the snout and a pair of hornlets over the eyes. The forelimbs were powerfully built but very short. The bones of the sacrum were fused (synsacrum) and the pelvic bones were fused together and to this structure (Sereno 1997) (i.e. similar to modern birds). A row of small osteoderms was present down the middle of the back. Ceratosaurus, at first glance, looked like a fairly typical theropod, however its skull was quite large in proportion to the rest of its body and possessed a prominent nose horn formed from protuberances of the nasal bones.mIn addition to the large nasal horn, Ceratosaurus possessed smaller hornlike ridges in front of each eye, similar to those of Allosaurus, these ridges were formed by enlargement of the lacrimal bones. Uniquely among theropods, Ceratosaurus possessed dermal armor, in the form of small osteoderms running down the middle of its back. Its tail comprised about half of the body's total length and was thin and flexible, with high vertebral spines. The type specimen was an individual about 18 feet (5.5 m) long; it is not clear whether this animal was fully grown. David B. Norman (1985) estimated that the maximum length of Ceratosaurus was 20 ft (6.1 m), an assessment supported by a particularly large Ceratosaurus specimen from the Cleveland-Lloyd Quarry (UMNH 5728), discovered in the mid-1960s, which may have been 22 ft (6.7 m) long assuming similar proportions to the holotype. Marsh (1884) suggested that Ceratosaurus weighed about half as much as Allosaurus. In Predatory Dinosaurs of the World, published in 1988, Gregory S. Paul estimated that the C. nasicornis holotype skeleton came from an animal weighing about 524 kilograms (1,155 lb) while the large material from the Cleveland-Lloyd Quarry represents a much bigger and heavier individual, whose bulk he estimated at about 980 kilograms (2,160 lb). The bigger specimen was later assigned by James H. Madsen and Samuel P. Welles to the new species C. dentisulcatus. A considerably lower figure was proposed by John Foster, a specialist on the Morrison Formation, in 2007. Foster used an equation provided by J.F. Anderson and colleagues to estimate mass from femur length, which yielded an approximate weight of 275 kilograms (606 lb) for C. magnicornis and 452 kilograms (996 lb) for C. dentisulcatus.
Allosaurus /ˌælɵˈsɔrəs/ is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period (Kimmeridgian to early Tithonian). The name "Allosaurus" means "different lizard". It is derived from the Greek ἄλλος/allos ("different, other") and σαῦρος/sauros ("lizard / generic reptile"). The first fossil remains that can definitely be ascribed to this genus were described in 1877 by paleontologist Othniel Charles Marsh, and it became known as Antrodemus. As one of the first well-known theropod dinosaurs, it has long attracted attention outside of paleontological circles. Indeed, it has been a top feature in several films and documentaries about prehistoric life. Allosaurus was a large bipedal predator. Its skull was large and equipped with dozens of large, sharp teeth. It averaged 8.5 m (28 ft) in length, though fragmentary remains suggest it could have reached over 12 m (39 ft). Relative to the large and powerful hindlimbs, its three-fingered forelimbs were small, and the body was balanced by a long and heavily muscled tail. It is classified as an allosaurid, a type of carnosaurian theropod dinosaur. The genus has a complicated taxonomy, and includes an uncertain number of valid species, the best known of which is A. fragilis. The bulk of Allosaurus remains have come from North America's Morrison Formation, with material also known from Portugal and possibly Tanzania. It was known for over half of the 20th century as Antrodemus, but study of the copious remains from the Cleveland-Lloyd Dinosaur Quarry brought the name "Allosaurus" back to prominence, and established it as one of the best-known dinosaurs. As the most abundant large predator in the Morrison Formation, Allosaurus was at the top of the food chain, probably preying on contemporaneous large herbivorous dinosaurs and perhaps even other predators. Potential prey included ornithopods, stegosaurids, and sauropods. Some paleontologists interpret Allosaurus as having had cooperative social behavior, 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. It may have attacked large prey by ambush, using its upper jaw like a hatchet.
Ceratosaurus spp.
Ceratosaurus /ˌsɛrətɵˈsɔrəs/ meaning "horned lizard", in reference to the horn on its nose (Greek κερας/κερατος, keras/keratos meaning "horn" and σαυρος/sauros meaning "lizard"), was a large predatory theropod dinosaur from the Late Jurassic Period (Kimmeridgian to Tithonian), found in the Morrison Formation of North America, and the Lourinhã Formation of Portugal. It was characterized by large jaws with blade-like teeth, a large, blade-like horn on the snout and a pair of hornlets over the eyes. The forelimbs were powerfully built but very short. The bones of the sacrum were fused (synsacrum) and the pelvic bones were fused together and to this structure (Sereno 1997) (i.e. similar to modern birds). A row of small osteoderms was present down the middle of the back. Ceratosaurus, at first glance, looked like a fairly typical theropod, however its skull was quite large in proportion to the rest of its body and possessed a prominent nose horn formed from protuberances of the nasal bones.mIn addition to the large nasal horn, Ceratosaurus possessed smaller hornlike ridges in front of each eye, similar to those of Allosaurus, these ridges were formed by enlargement of the lacrimal bones. Uniquely among theropods, Ceratosaurus possessed dermal armor, in the form of small osteoderms running down the middle of its back. Its tail comprised about half of the body's total length and was thin and flexible, with high vertebral spines. The type specimen was an individual about 18 feet (5.5 m) long; it is not clear whether this animal was fully grown. David B. Norman (1985) estimated that the maximum length of Ceratosaurus was 20 ft (6.1 m), an assessment supported by a particularly large Ceratosaurus specimen from the Cleveland-Lloyd Quarry (UMNH 5728), discovered in the mid-1960s, which may have been 22 ft (6.7 m) long assuming similar proportions to the holotype. Marsh (1884) suggested that Ceratosaurus weighed about half as much as Allosaurus. In Predatory Dinosaurs of the World, published in 1988, Gregory S. Paul estimated that the C. nasicornis holotype skeleton came from an animal weighing about 524 kilograms (1,155 lb) while the large material from the Cleveland-Lloyd Quarry represents a much bigger and heavier individual, whose bulk he estimated at about 980 kilograms (2,160 lb). The bigger specimen was later assigned by James H. Madsen and Samuel P. Welles to the new species C. dentisulcatus. A considerably lower figure was proposed by John Foster, a specialist on the Morrison Formation, in 2007. Foster used an equation provided by J.F. Anderson and colleagues to estimate mass from femur length, which yielded an approximate weight of 275 kilograms (606 lb) for C. magnicornis and 452 kilograms (996 lb) for C. dentisulcatus.
