Ammosaurus
Ammosaurus (AM-o-sawr-us) meaning "lizard of the sand", because it was found in sandstone ( Greek ammos = sand + sauros = lizard) has been identified by four incomplete skeletons found in United States and Canada regions. The first Ammosaurus skeleton was found in the late 1880s by a group of construction workers in the Connecticut Valley in the US, who were building a bridge at the time. The valley was once a swamp, on which Amosaurus would often search for food along its banks. Other fragmental skeletons have been found in Arizona and Nova Scotia.
When Othniel C. Marsh first identified Ammosaurus's remains, he confused them with those of another dinosaur, Anchisaurus. It was not until 1891 that he renamed the fossils as that of Ammosaurus. Ironically, some of the Anchisaurus remains were thought to be remains of prehistoric humans. Although no Ammosaurus skull has ever been found, enough fossil was found to determine that it was more closely related to Plateosaurus than Anchisaurus as previously thought.
Ammosaurus lived during the early Jurassic period, around 180 million years ago. It was a herbivore and could walk on both four or two feet, the latter undoubtedly allowing it to reach higher branches. It had large claws on its hands to allow it to strip bark from trees and saplings. Compared to the rest of its body, Ammosaurus had both a long tail & neck, suggesting that it would have walked on four legs for most of its life, only walking on two to defend itself or reach food. To defend itself, it would stand on its hind legs, slashing at its attacker with its large thumb claws on its fore legs.
Ammosaurus measured over 4.3 m (14 ft) long and stood about 1.8 m (6 ft) tall, although it would only be knee high if it was on all fours. Ammosaurus weighed around 290 kg (640 lb), mainly due to its large body. At its largest, it would grow to the size of a small car.
When Othniel C. Marsh first identified Ammosaurus's remains, he confused them with those of another dinosaur, Anchisaurus. It was not until 1891 that he renamed the fossils as that of Ammosaurus. Ironically, some of the Anchisaurus remains were thought to be remains of prehistoric humans. Although no Ammosaurus skull has ever been found, enough fossil was found to determine that it was more closely related to Plateosaurus than Anchisaurus as previously thought.
Ammosaurus lived during the early Jurassic period, around 180 million years ago. It was a herbivore and could walk on both four or two feet, the latter undoubtedly allowing it to reach higher branches. It had large claws on its hands to allow it to strip bark from trees and saplings. Compared to the rest of its body, Ammosaurus had both a long tail & neck, suggesting that it would have walked on four legs for most of its life, only walking on two to defend itself or reach food. To defend itself, it would stand on its hind legs, slashing at its attacker with its large thumb claws on its fore legs.
Ammosaurus measured over 4.3 m (14 ft) long and stood about 1.8 m (6 ft) tall, although it would only be knee high if it was on all fours. Ammosaurus weighed around 290 kg (640 lb), mainly due to its large body. At its largest, it would grow to the size of a small car.
Terrestrial Animals
On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs ( sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitales. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). All these belong to the "lizard hipped" or saurischian branch of the dinosaurs.
During the late Jurassic the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by birds.
Plants
The arid conditions that had characterized much of the Triassic steadily eased during the following period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape (Haines 2000). Flowering plants had not evolved yet, but conifers were common, and in fact were the most diverse group of trees, as were palms Kazlev (2002). Cycads were abundant, as were ginkgos and tree ferns in the forest; smaller ferns were probably the dominant undergrowth Kazlev (2002). In the Southern Hemisphere, podocarps were especially successful (Haines 2000).Terrestrial Animals
On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs ( sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitales. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). All these belong to the "lizard hipped" or saurischian branch of the dinosaurs.
During the late Jurassic the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by birds.
Plants
The arid conditions that had characterized much of the Triassic steadily eased during the following period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape (Haines 2000). Flowering plants had not evolved yet, but conifers were common, and in fact were the most diverse group of trees, as were palms Kazlev (2002). Cycads were abundant, as were ginkgos and tree ferns in the forest; smaller ferns were probably the dominant undergrowth Kazlev (2002). In the Southern Hemisphere, podocarps were especially successful (Haines 2000).
On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs ( sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitales. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). All these belong to the "lizard hipped" or saurischian branch of the dinosaurs.
During the late Jurassic the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by birds.
Plants
The arid conditions that had characterized much of the Triassic steadily eased during the following period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape (Haines 2000). Flowering plants had not evolved yet, but conifers were common, and in fact were the most diverse group of trees, as were palms Kazlev (2002). Cycads were abundant, as were ginkgos and tree ferns in the forest; smaller ferns were probably the dominant undergrowth Kazlev (2002). In the Southern Hemisphere, podocarps were especially successful (Haines 2000).Terrestrial Animals
On land, large archosaurian reptiles remained dominant. Great plant-eating dinosaurs ( sauropods) roamed the land, feeding on prairies of ferns and palm-like cycads and bennettitales. They were preyed upon by large theropods (Ceratosaurs, Megalosaurs, and Allosaurs). All these belong to the "lizard hipped" or saurischian branch of the dinosaurs.
During the late Jurassic the first birds evolved from small coelurosaur dinosaurs. Ornithischian dinosaurs were less predominant than saurischian dinosaurs, although some like stegosaurs and small ornithopods played important roles as small and medium-to-large (but not sauropod large) herbivores. In the air, pterosaurs were common, filling many ecological roles now taken by birds.
Plants
The arid conditions that had characterized much of the Triassic steadily eased during the following period, especially at higher latitudes; the warm, humid climate allowed lush jungles to cover much of the landscape (Haines 2000). Flowering plants had not evolved yet, but conifers were common, and in fact were the most diverse group of trees, as were palms Kazlev (2002). Cycads were abundant, as were ginkgos and tree ferns in the forest; smaller ferns were probably the dominant undergrowth Kazlev (2002). In the Southern Hemisphere, podocarps were especially successful (Haines 2000).
No comments:
Post a Comment