Post by DinosaurMichael on Mar 12, 2012 8:47:21 GMT -5
Marsupial Lion - Thylacoleo carnifex
The Marsupial Lion (Thylacoleo carnifex, the "murderous (or 'meat-cutting') marsupial lion" from thylakos - pouch, leo - lion, carnifex - murderer, tormentor, 'butcher') 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). 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 (29.5 in) high at the shoulder and about 150 cm (60 in) from head to tail. Measurements taken from a number of specimens show that they averaged 100 to 130 kg (220 to 285 lb) in weight although individuals heavier than 160 kg (350 lb) may not have been uncommon. 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 forelimbs. 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 semi-opposable and bore an enlarged claw. Palaeontologists believe that this would have been used to grapple with and slash at 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.
Thylacosmilus - Thylacosmilus atrox
Thylacosmilus ("pouch sabre") was a genus of sabre-toothed metatherian predators that first appeared during the Miocene. Remains of the animal have been found in parts of South America, primarily Argentina. 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. Thylacosmilus had long, sabre-like upper canines and short, blunt, peg-like lower canines. The incisors were missing altogether and the other teeth were severely reduced, but, as distinct from machairodonts, their number was complete. It is estimated to have weighed around 150 kilograms (330 lb). Thylacosmilus and the similarly sized Marsupial Lion were the largest carnivorous metatherians. Thylacosmilus' sabre-teeth kept growing throughout its life, unlike those of true sabre-toothed felines. It also had a pair of elongated, scabbard-like flanges growing from the lower jaw, which protected the sabre-teeth when it closed its mouth. The cervical vertebrae were very strong and to some extent resembled the vertebrae of machairodonts. Thylacosmilus went extinct during the Pliocene, a timeframe closely corresponding to the arrival of the sabre-toothed cat Smilodon from North America in the Great American Interchange. Out-competition from the anatomically similar Smilodon appears to have driven the extinction, though this is not typical of other South American extinctions during the period.
The Marsupial Lion (Thylacoleo carnifex, the "murderous (or 'meat-cutting') marsupial lion" from thylakos - pouch, leo - lion, carnifex - murderer, tormentor, 'butcher') 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). 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 (29.5 in) high at the shoulder and about 150 cm (60 in) from head to tail. Measurements taken from a number of specimens show that they averaged 100 to 130 kg (220 to 285 lb) in weight although individuals heavier than 160 kg (350 lb) may not have been uncommon. 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 forelimbs. 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 semi-opposable and bore an enlarged claw. Palaeontologists believe that this would have been used to grapple with and slash at 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.
Thylacosmilus - Thylacosmilus atrox
Thylacosmilus ("pouch sabre") was a genus of sabre-toothed metatherian predators that first appeared during the Miocene. Remains of the animal have been found in parts of South America, primarily Argentina. 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. Thylacosmilus had long, sabre-like upper canines and short, blunt, peg-like lower canines. The incisors were missing altogether and the other teeth were severely reduced, but, as distinct from machairodonts, their number was complete. It is estimated to have weighed around 150 kilograms (330 lb). Thylacosmilus and the similarly sized Marsupial Lion were the largest carnivorous metatherians. Thylacosmilus' sabre-teeth kept growing throughout its life, unlike those of true sabre-toothed felines. It also had a pair of elongated, scabbard-like flanges growing from the lower jaw, which protected the sabre-teeth when it closed its mouth. The cervical vertebrae were very strong and to some extent resembled the vertebrae of machairodonts. Thylacosmilus went extinct during the Pliocene, a timeframe closely corresponding to the arrival of the sabre-toothed cat Smilodon from North America in the Great American Interchange. Out-competition from the anatomically similar Smilodon appears to have driven the extinction, though this is not typical of other South American extinctions during the period.
