Post by DinosaurMichael on Jul 6, 2012 15:24:22 GMT -5
Komodo Dragon - Varanus komodoensis
The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang and Gili Dasami. A member of the monitor lizard family (Varanidae), it is the largest living species of lizard, growing to a maximum length of 3 metres (9.8 ft) in rare cases and weighing up to around 70 kilograms (150 lb). Their unusual size has been attributed to island gigantism, since there are no other carnivorous animals to fill the niche on the islands where they live. However, recent research suggests that the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka." As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. Their group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. In the wild, an adult Komodo dragon usually weighs around 70 kilograms (150 lb), although captive specimens often weigh more. The largest verified wild specimen was 3.13 metres (10 ft 3 in) long and weighed 166 kilograms (370 lb), including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced serrated teeth that can measure up to 2.5 centimetres (1 in) in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue.
Eryops - Eryops megacephalus
Eryops ( /ˈɛəri.ɒps/) meaning "drawn-out face" because most of its skull was in front of its eyes (Greek åñõåéí, eryein = drawn-out + ùø, ops = face) is a genus of extinct, semi-aquatic amphibian found primarily in the Lower Permian-aged Admiral Formation (about 295 million years ago) of Archer County, Texas, but fossils are also found in New Mexico and parts of the eastern United States. Eryops also occurs in older Pennsylvanian strata of the Conemaugh Group in West Virginia Eryops averaged a little over 1.5-2.0 meters (5–6 ft) long, making it one of the largest land animals of its time. It weighed about 90 kilograms (200 lb). It probably had few predators though it would have likely been an easy target for a predator like Dimetrodon which was larger and was likely the apex predator at the time. Several complete skeletons of Eryops have been found in the Lower Permian, but skull plates and teeth are the most common fossils. Although it had no direct descendants, it is the best-known Permian amphibian and a remarkable example of natural engineering. Eryops is an example of an animal that made successful adaptations in the movement from a water environment to a terrestrial one. It retained, and refined, most of the traits found in its fish ancestors. Sturdy limbs supported and transported its body while out of water. A thicker, stronger backbone prevented its body from sagging under its own weight. Also, by utilizing vestigial fish jaw bones, a rudimentary ear was developed, allowing Eryops to hear airborne sound. The skull of Eryops is proportionately large, being broad and flat and reaching lengths of 60 centimeters (2 ft). The skull resembled that of a salamander. It had an enormous mouth with many sharp teeth in strong jaws. Its teeth had enamel with a folded pattern, hence its classification with the labyrinthodonts ("maze toothed"). Within the wide, gaping jaw, the fang-like palatal teeth, when coupled with the gape, suggest an inertial feeding habit. This is when the amphibian would grasp its prey and, lacking any chewing mechanism, toss its head up and backwards, throwing the prey farther back into its mouth. Such feeding is seen today in the crocodile and alligator. It is taken that Eryops was not very active, thus a predatory lifestyle, while possible, was probably not the norm. It is more likely that it fed on fish either in the water or on those that became stranded at the margins of lakes and swamps. A large supply of terrestrial invertebrates were also abundant at the time, and this may have provided a fairly adequate food supply in itself.
The Komodo dragon (Varanus komodoensis), also known as the Komodo monitor, is a large species of lizard found in the Indonesian islands of Komodo, Rinca, Flores, Gili Motang and Gili Dasami. A member of the monitor lizard family (Varanidae), it is the largest living species of lizard, growing to a maximum length of 3 metres (9.8 ft) in rare cases and weighing up to around 70 kilograms (150 lb). Their unusual size has been attributed to island gigantism, since there are no other carnivorous animals to fill the niche on the islands where they live. However, recent research suggests that the large size of Komodo dragons may be better understood as representative of a relict population of very large varanid lizards that once lived across Indonesia and Australia, most of which, along with other megafauna, died out after the Pleistocene. Fossils very similar to V. komodoensis have been found in Australia dating to greater than 3.8 million years ago, and its body size remained stable on Flores, one of the handful of Indonesian islands where it is currently found, over the last 900,000 years, "a time marked by major faunal turnovers, extinction of the island's megafauna, and the arrival of early hominids by 880 ka." As a result of their size, these lizards dominate the ecosystems in which they live. Komodo dragons hunt and ambush prey including invertebrates, birds, and mammals. Their group behaviour in hunting is exceptional in the reptile world. The diet of big Komodo dragons mainly consists of deer, though they also eat considerable amounts of carrion. In the wild, an adult Komodo dragon usually weighs around 70 kilograms (150 lb), although captive specimens often weigh more. The largest verified wild specimen was 3.13 metres (10 ft 3 in) long and weighed 166 kilograms (370 lb), including undigested food. The Komodo dragon has a tail as long as its body, as well as about 60 frequently replaced serrated teeth that can measure up to 2.5 centimetres (1 in) in length. Its saliva is frequently blood-tinged, because its teeth are almost completely covered by gingival tissue that is naturally lacerated during feeding. This creates an ideal culture for the bacteria that live in its mouth. It also has a long, yellow, deeply forked tongue.
Eryops - Eryops megacephalus
Eryops ( /ˈɛəri.ɒps/) meaning "drawn-out face" because most of its skull was in front of its eyes (Greek åñõåéí, eryein = drawn-out + ùø, ops = face) is a genus of extinct, semi-aquatic amphibian found primarily in the Lower Permian-aged Admiral Formation (about 295 million years ago) of Archer County, Texas, but fossils are also found in New Mexico and parts of the eastern United States. Eryops also occurs in older Pennsylvanian strata of the Conemaugh Group in West Virginia Eryops averaged a little over 1.5-2.0 meters (5–6 ft) long, making it one of the largest land animals of its time. It weighed about 90 kilograms (200 lb). It probably had few predators though it would have likely been an easy target for a predator like Dimetrodon which was larger and was likely the apex predator at the time. Several complete skeletons of Eryops have been found in the Lower Permian, but skull plates and teeth are the most common fossils. Although it had no direct descendants, it is the best-known Permian amphibian and a remarkable example of natural engineering. Eryops is an example of an animal that made successful adaptations in the movement from a water environment to a terrestrial one. It retained, and refined, most of the traits found in its fish ancestors. Sturdy limbs supported and transported its body while out of water. A thicker, stronger backbone prevented its body from sagging under its own weight. Also, by utilizing vestigial fish jaw bones, a rudimentary ear was developed, allowing Eryops to hear airborne sound. The skull of Eryops is proportionately large, being broad and flat and reaching lengths of 60 centimeters (2 ft). The skull resembled that of a salamander. It had an enormous mouth with many sharp teeth in strong jaws. Its teeth had enamel with a folded pattern, hence its classification with the labyrinthodonts ("maze toothed"). Within the wide, gaping jaw, the fang-like palatal teeth, when coupled with the gape, suggest an inertial feeding habit. This is when the amphibian would grasp its prey and, lacking any chewing mechanism, toss its head up and backwards, throwing the prey farther back into its mouth. Such feeding is seen today in the crocodile and alligator. It is taken that Eryops was not very active, thus a predatory lifestyle, while possible, was probably not the norm. It is more likely that it fed on fish either in the water or on those that became stranded at the margins of lakes and swamps. A large supply of terrestrial invertebrates were also abundant at the time, and this may have provided a fairly adequate food supply in itself.
