Description Marsupial lion

skeleton of marsupial lion (thylacoleo carnifex) in victoria fossil cave, naracoorte caves national park, south australia

the marsupial lion largest meat-eating mammal known have ever existed in australia, , 1 of largest marsupial carnivores anywhere in world (although see thylacosmilus , borhyaena). individuals ranged around 75 cm (30 in) high @ shoulder , 150 cm (59 in) head tail. measurements taken number of specimens show averaged 101 130 kg (223 287 lb) in weight, although individuals large 124–160 kg (273–353 lb) might not have been uncommon, , largest weight of 128–164 kg (282–362 lb). make comparable female lions , female tigers in general size.

the animal extremely robust powerfully built jaws , strong fore limbs. possessed retractable claws, unique trait among marsupials. have allowed claws remain sharp protecting them being worn down on hard surfaces. claws well-suited securing prey , climbing trees. first digits ( thumbs ) on each hand semiopposable , bore enlarged claw. palaeontologists believe have been used grapple intended prey, providing sure footing on tree trunks , branches. hind feet had 4 functional toes, first digit being reduced in size, possessing roughened pad similar of possums, may have assisted climbing. unclear whether marsupial lion exhibited syndactyly (fused second , third toes) other diprotodonts.

the marsupial lion s hindquarters well-developed, although lesser extent front of animal. remains of animal show had relatively thick , strong tail , vertebrae possessed chevrons on undersides tail have contacted ground. these have served protect critical elements such nerves , blood vessels if animal used tail support when on hind legs, present day kangaroos do. taking stance free fore limbs tackle or slash @ intended victim.

evolutionary relationships

the ancestors of thylacoleonids believed have been herbivores, unusual carnivores cranial features , arboreal characteristics suggest thylacoleonids share common ancestor wombats. while other continents sharing many of predators amongst themselves, connected land, australia s isolation caused many of docile herbivorous species turn carnivorous. possum-like features once thought indicate marsupial lion s evolutionary path phalangeriform ancestor, however, scientists agree more prominent features suggest vombatiform ancestry. however, discovered microleo possum-like animal.

dentition

skull of t. carnifex showing incisors , blade-like carnassial premolars

the marsupial lion highly specialised carnivore, reflected in dentition. other diprotodonts, possessed enlarged incisors on both upper (maxillae) , lower (mandibles) jaws. these teeth (the lower in particular) shaped more pointed canine teeth of animals such dogs , cats of kangaroos. unusual feature of creature s dentition huge, blade-like carnassial premolars on either side of jaws. top , bottom carnassials worked shears , have been effective @ slicing off chunks of flesh carcasses , cutting through bone.

the jaw muscle of marsupial lion exceptionally large size, giving extremely powerful bite. biometric calculations show, considering size, had strongest bite of known mammal, living or extinct; 101-kg individual have had bite comparable of 250-kg african lion. using 3d modeling based on x-ray computed tomography scans, marsupial lions found unable use prolonged, suffocating bite typical of living big cats. instead had extremely efficient , unique bite; incisors have been used stab @ , pierce flesh of prey while more specialised carnassials crushed windpipe, severed spinal cord, , lacerated major blood vessels such carotid artery , jugular vein. compared african lion may take 15 minutes kill large catch, marsupial lion kill large animal in less minute. skull specialized big game inefficient @ catching smaller animals, possibly contributed extinction.