Post by Infinity Blade on Apr 14, 2014 23:54:43 GMT 5
Marsupial Lion-Thylacoleo carnifex
The marsupial lion (Thylacoleo carnifex) is an extinct species of carnivorous marsupial mammal that lived in Australia from the early to the late Pleistocene (1,600,000–46,000 years ago).[1] Despite its name, it is not closely related to the lion, but is a member of the order Diprotodontia. The marsupial lion is the largest meat-eating mammal known to have ever existed in Australia, and one of the largest marsupial carnivores from anywhere in the world (although see Thylacosmilus and Borhyaena). Individuals ranged up to around 75 cm (30 in) high at the shoulder and about 150 cm (59 in) from head to tail. Measurements taken from a number of specimens show they averaged 100 to 130 kg (220 to 290 lb) in weight although individuals heavier than 160 kg (350 lb) might not have been uncommon.[2] This would make it quite comparable to female lions and tigers in general size. The animal was extremely robust with powerfully built jaws and very strong fore limbs. It possessed retractable claws, a unique trait among marsupials. This would have allowed the claws to remain sharp by protecting them from being worn down on hard surfaces. The claws were well-suited to securing prey and for climbing trees. The first digits ("thumbs") on each hand were semiopposable and bore an enlarged claw. Palaeontologists believe this would have been used to grapple its intended prey, as well as providing it with a sure footing on tree trunks and branches. The hind feet had four functional toes, the first digit being much reduced in size but possessing a roughened pad similar to that of possums, which may have assisted with climbing. It is unclear whether the marsupial lion exhibited syndactyly (fused second and third toes) like other diprotodonts. The marsupial lion's hindquarters were also well-developed, although to a lesser extent than the front of the animal. Remains of the animal show that it had a relatively thick and strong tail and that the vertebrae possessed chevrons on their undersides where the tail would have contacted the ground. These would have served to protect critical elements such as nerves and blood vessels if the animal used its tail to support itself when on its hind legs, much like present day kangaroos do. Taking this stance would free up its forelimbs to tackle or slash at its intended victim.[3]
Thylacosmilus atrox
Thylacosmilus atrox is an extinct species of saber-toothed metatherian that inhabited South America from the late Miocene to late Pliocene epochs. Remains of this animal have been found primarily in the provinces of Catamarca, Entre Ríos, and La Pampa in northern Argentina.[2] Though Thylacosmilus is one of several predatory mammal genera typically called "sabre-toothed cats", it was not a felid but a sparassodont, a group closely related to marsupials, and only superficially resembled other sabre-toothed mammals due to convergent evolution. The most notable feature of Thylacosmilus is its canines, which are saber-like and whose roots grew throughout the animal’s life, growing in an arc up the maxilla and even above the orbits.[3] Its cervical vertebrae were very strong and to some extent resembled the vertebrae of machairodonts.[4] Recent comparative biomechanical analysis have estimated the bite force of T. atrox starting at maximum gape at 38 newtons (8.5 lbf), much weaker than that of a leopard, suggesting its jaw muscles had an insignificant role on the dispatch of prey. Its skull was similar to that of Smilodon in that it was much better adapted to withstand loads applied by the neck musculature, which, along with evidence for powerful and flexible forelimb musculature and other skeleton adaptations for stability, support the hypothesis that its killing method consisted on immobilization of its prey followed by precisely directed, deep bites into the soft tissue driven by powerful neck muscles.[5][6] Body mass estimates of Thylacosmilus suggest this animal weighed between 80 and 120 kg (170 and 260 lb), about the same size as a modern jaguar or leopard.[7][8] This would make it one of the largest known carnivorous metatherians. Although older references have often stated that Thylacosmilus went extinct due to competition with the “more competitive” saber-toothed cat Smilodon during the Great American Biotic Interchange, newer studies have shown this is not the case. Thylacosmilus died out during the late Pliocene, whereas saber-toothed cats are not known from South America until the middle Pleistocene epoch.[7] As a result, the last appearance of Thylacosmilus is separated from the first appearance of Smilodon by over one and a half million years.
The marsupial lion (Thylacoleo carnifex) is an extinct species of carnivorous marsupial mammal that lived in Australia from the early to the late Pleistocene (1,600,000–46,000 years ago).[1] Despite its name, it is not closely related to the lion, but is a member of the order Diprotodontia. The marsupial lion is the largest meat-eating mammal known to have ever existed in Australia, and one of the largest marsupial carnivores from anywhere in the world (although see Thylacosmilus and Borhyaena). Individuals ranged up to around 75 cm (30 in) high at the shoulder and about 150 cm (59 in) from head to tail. Measurements taken from a number of specimens show they averaged 100 to 130 kg (220 to 290 lb) in weight although individuals heavier than 160 kg (350 lb) might not have been uncommon.[2] This would make it quite comparable to female lions and tigers in general size. The animal was extremely robust with powerfully built jaws and very strong fore limbs. It possessed retractable claws, a unique trait among marsupials. This would have allowed the claws to remain sharp by protecting them from being worn down on hard surfaces. The claws were well-suited to securing prey and for climbing trees. The first digits ("thumbs") on each hand were semiopposable and bore an enlarged claw. Palaeontologists believe this would have been used to grapple its intended prey, as well as providing it with a sure footing on tree trunks and branches. The hind feet had four functional toes, the first digit being much reduced in size but possessing a roughened pad similar to that of possums, which may have assisted with climbing. It is unclear whether the marsupial lion exhibited syndactyly (fused second and third toes) like other diprotodonts. The marsupial lion's hindquarters were also well-developed, although to a lesser extent than the front of the animal. Remains of the animal show that it had a relatively thick and strong tail and that the vertebrae possessed chevrons on their undersides where the tail would have contacted the ground. These would have served to protect critical elements such as nerves and blood vessels if the animal used its tail to support itself when on its hind legs, much like present day kangaroos do. Taking this stance would free up its forelimbs to tackle or slash at its intended victim.[3]
Thylacosmilus atrox
Thylacosmilus atrox is an extinct species of saber-toothed metatherian that inhabited South America from the late Miocene to late Pliocene epochs. Remains of this animal have been found primarily in the provinces of Catamarca, Entre Ríos, and La Pampa in northern Argentina.[2] Though Thylacosmilus is one of several predatory mammal genera typically called "sabre-toothed cats", it was not a felid but a sparassodont, a group closely related to marsupials, and only superficially resembled other sabre-toothed mammals due to convergent evolution. The most notable feature of Thylacosmilus is its canines, which are saber-like and whose roots grew throughout the animal’s life, growing in an arc up the maxilla and even above the orbits.[3] Its cervical vertebrae were very strong and to some extent resembled the vertebrae of machairodonts.[4] Recent comparative biomechanical analysis have estimated the bite force of T. atrox starting at maximum gape at 38 newtons (8.5 lbf), much weaker than that of a leopard, suggesting its jaw muscles had an insignificant role on the dispatch of prey. Its skull was similar to that of Smilodon in that it was much better adapted to withstand loads applied by the neck musculature, which, along with evidence for powerful and flexible forelimb musculature and other skeleton adaptations for stability, support the hypothesis that its killing method consisted on immobilization of its prey followed by precisely directed, deep bites into the soft tissue driven by powerful neck muscles.[5][6] Body mass estimates of Thylacosmilus suggest this animal weighed between 80 and 120 kg (170 and 260 lb), about the same size as a modern jaguar or leopard.[7][8] This would make it one of the largest known carnivorous metatherians. Although older references have often stated that Thylacosmilus went extinct due to competition with the “more competitive” saber-toothed cat Smilodon during the Great American Biotic Interchange, newer studies have shown this is not the case. Thylacosmilus died out during the late Pliocene, whereas saber-toothed cats are not known from South America until the middle Pleistocene epoch.[7] As a result, the last appearance of Thylacosmilus is separated from the first appearance of Smilodon by over one and a half million years.
