''Thylacoleo'' ("pouch lion") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

genus of carnivorous marsupials that lived in

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

ian predators in Australia of their time, with '' Thylacoleo carnifex'' approaching the weight of a

lion The lion (''Panthera leo'') is a large Felidae, cat of the genus ''Panthera'' native to Africa and India. It has a muscular, broad-chested body; short, rounded head; round ears; and a hairy tuft at the end of its tail. It is sexually dimorphi ...

ess. The estimated average weight for the species ranges from .

Taxonomy

The genus was first published in 1859, erected to describe the type species ''Thylacoleo carnifex''. The new taxon was established in examination of fossil specimens provided to

Richard Owen Sir Richard Owen (20 July 1804 – 18 December 1892) was an English biologist, comparative anatomist and paleontologist. Owen is generally considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Owe ...

. The familial alliance takes its name from this description, the so-called marsupial lions of Thylacoleonidae. The colloquial name "marsupial lion" alludes to the superficial resemblance to the placental lion and its ecological niche as a large predator. ''Thylacoleo'' is not closely related to the modern lion ('' Panthera leo''). Genus: ''Thylacoleo'' (''Thylacopardus'') – Australia's marsupial lions, that lived from about 2 million years ago, during the Late Pliocene Epoch and became extinct about 30,000 years ago, during the Late Pleistocene Epoch. Three species are known: *''Thylacoleo carnifex'' The holotype cranium was collected from

Lake Colongulac A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in 1843 by pastoralist William Adeney. A partial rostrum collected by Adeney in 1876 from the same locality would later be found to belong to the same individual. *''Thylacoleo crassidentatus'' lived during the Pliocene, around 5 million years ago, and was about the size of a large dog. Its fossils have been found in southeastern Queensland. *''Thylacoleo hilli'' lived during the Pliocene and was half the size of ''T. crassidentatus''. It is the oldest member of the genus. Fossils of other representatives of Thylacoleonidae, such as '' Microleo'' and '' Wakaleo'', date back to the Late Oligocene Epoch, some 24 million years ago. ''T. hilli'' was described by

Neville Pledge Neville may refer to: Places *Neville, New South Wales, Australia *Neville, Saskatchewan, Canada *Néville, in the Seine-Maritime department, France *Néville-sur-Mer, in the Manche department, France *Neville, Ohio, USA *Neville Township, Penns ...

in a study published in the records of the South Australia Museum in 1977. The holotype is a third premolar, discovered at a cave in

Curramulka Curramulka is a town in the Australian state of South Australia on the Yorke Peninsula. Curramulka is within easy driving distance of the coastal resort towns of Port Victoria and Port Vincent and is north-east of Minlaton. At the , Curramu ...

in South Australia, exhibiting the carnivorous characteristics of the genus and around half the size of ''T. carnifex''. This tooth was collected by Alan Hill, a speleologist and founding member of the Cave Exploration Group of South Australia, while examining a site known as the "Town Cave" in 1956; the specific epithet ''hilli'' honours the collector of the first specimen. Material found amidst the fauna at Bow River in New South Wales, dated to the early Pliocene, was also referred to the species in 1982. A fragment of an incisor, unworn and only diagnosable to the genus, was located at a site in Curramulka, close to the Town Cave site, and referred to the species for the apparent correlation in size when compared to the better known ''T. carnifex''. The marsupial lion is classified in the order Diprotodontia along with many other well-known marsupials such as kangaroos,

possums Possum may refer to: Animals * Phalangeriformes, or possums, any of a number of arboreal marsupial species native to Australia, New Guinea, and Sulawesi ** Common brushtail possum (''Trichosurus vulpecula''), a common possum in Australian urban a ...

, and the koala. It is further classified in its own family, the Thylacoleonidae, of which three

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

and 11 species are recognised, all extinct. The term marsupial lion (lower case) is often applied to other members of this family. Distinct possum-like characteristics led ''Thylacoleo'' to be regarded as members of

Phalangeroidea The Phalangeroidea are a superfamily of mammals that include the families Burramyidae and Phalangeridae The Phalangeridae are a family of mostly nocturnal marsupials native to Australia, New Guinea, and Eastern Indonesia, including the cusc ...

for a few decades. Though a few authors continued to hint at phalangeroid affinities for thylacoleonids as recently as the 1990s, cranial and other characters have generally led to their inclusion within vombatiformes, and as stem-members of the wombat lineage. Marsupial lions and other ecologically and morphologically diverse vombatiforms were once represented by over 60 species of

carnivorous A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other sof ...

, herbivorous, terrestrial and arboreal forms ranging in size from 3 kg to 2.5 tonnes. Only two families represented by four herbivorous species (koalas and three species of wombat) have survived into modern times and are considered the marsupial lion's closest living relatives.

Evolution

The ancestors of thylacoleonids are believed to have been

herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthpart ...

s, something unusual for carnivores. They are members of the Vombatiformes, an almost entirely herbivorous order of marsupials, the only extant representatives of which are koalas and wombats, as well as extinct members such as the diprotodontids and

palorchestids Palorchestidae is an extinct family of diprotodont marsupials whose members are sometimes referred to as marsupial tapirs due to their superficial similarity to true tapirs. Genera The family consists of the following four genera: * ''Propalorc ...

. The group first appeared in the Late

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

. The earliest thylacoleonids like '' Microleo'' were small possum-like animals, with the group increasing in size during the Miocene, with representatives like the leopoard sized '' Wakaleo.'' The genus ''Thylacoleo'' first appeared during the Pliocene, and represented the only extant genus of the family from that time until the end of the Pleistocene. The youngest representative of ''Thylacoleo'' and the thylacoleonids, ''T. carnifex'', is the largest known member of the family.

Description

''T. carnifex'' is the largest carnivorous

known to have ever existed in Australia, and one of the larger

metatheria Metatheria is a mammalian clade that includes all mammals more closely related to marsupials than to placentals. First proposed by Thomas Henry Huxley in 1880, it is a more inclusive group than the marsupials; it contains all marsupials as well ...

n carnivores of the world (comparable to '' Thylacosmilus'' and ''

Borhyaena ''Borhyaena'' is an extinct genus of South American metatherian, living between 17.5 and 15.5 million years ago in Patagonia, Argentina ( Santa Cruz and Sarmiento Formations) and Chile ( Río Frias Formation).''Proborhyaena gigantea''). Individuals ranged up to around high at the shoulder and about from head to tail. Measurements taken from a number of specimens show they averaged in weight, although individuals as large as might not have been uncommon, and the largest weight was of . This would make it comparable to female lions and female tigers in general size.

Bite

Pound for pound, ''T. carnifex'' had the strongest bite of any

species, living or extinct; a ''T. carnifex'' weighing had a bite comparable to that of a 250 kg African

, and research suggests that ''Thylacoleo'' could hunt and take prey much larger than itself. Larger animals that were likely prey include '' Diprotodon'' spp. and giant kangaroos. It seems improbable that ''Thylacoleo'' could achieve as high a bite force as a modern-day lion; however, this might have been possible when taking into consideration the size of its brain and skull. Carnivores usually have rather large brains when compared to herbivorous marsupials, which lessens the amount of bone that can be devoted to enhancing bite force. ''Thylacoleo'' however, is thought to have had substantially stronger muscle attachments and therefore a smaller brain. Using

3D modeling In 3D computer graphics, 3D modeling is the process of developing a mathematical coordinate-based representation of any surface of an object (inanimate or living) in three dimensions via specialized software by manipulating edges, vertices, an ...

based on X-ray computed tomography scans, marsupial lions were found to be unable to use the prolonged, suffocating bite typical of living big cats. They instead had an extremely efficient and unique bite; the incisors would have been used to stab at and pierce the flesh of their prey while the more specialised carnassials crushed the windpipe, severed the spinal cord, and lacerated the major blood vessels such as the

carotid artery Carotid artery may refer to: * Common carotid artery, often "carotids" or "carotid", an artery on each side of the neck which divides into the external carotid artery and internal carotid artery * External carotid artery, an artery on each side of t ...

and jugular vein. Compared to an African lion which may take 15 minutes to kill a large catch, the marsupial lion could kill a large animal in less than a minute. The skull was so specialized for big game that it was very inefficient at catching smaller animals, which possibly contributed to its extinction.

Postcranium

Thylacoleo skeleton in Naracoorte Caves (cropped)

''Thylacoleo'' had extremely strong forelimbs, with retractable, cat-like claws, a trait previously unseen in marsupials. ''Thylacoleo'' also possessed enormous hooked claws set on large semi-opposable thumbs, which were used to capture and disembowel prey. The long muscular tail was similar to that of a kangaroo. Specialised tail bones called chevrons allowed the animal to balance on its back legs, and freed the front legs for slashing and grasping. Retractable claws would remain sharp by protecting them from being worn down on hard surfaces. The first digits ("

thumbs The thumb is the first digit of the hand, next to the index finger. When a person is standing in the medical anatomical position (where the palm is facing to the front), the thumb is the outermost digit. The Medical Latin English noun for thumb ...

") on each hand were semi-opposable 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

, which may have assisted with climbing. The discovery in 2005 of a specimen which included complete hind feet provided evidence that the marsupial lion exhibited syndactyly (fused second and third toes) like other diprotodonts. Its strong forelimbs and retracting claws mean that ''Thylacoleo'' possibly climbed trees and perhaps carried carcasses to keep the kill for itself (similar to the

leopard The leopard (''Panthera pardus'') is one of the five extant species in the genus '' Panthera'', a member of the cat family, Felidae. It occurs in a wide range in sub-Saharan Africa, in some parts of Western and Central Asia, Southern Russia, a ...

today). The climbing ability would have also helped them climb out of caves, which could therefore have been used as dens to rear their young. Due to its unique predatory morphology, some scientists have claimed ''Thylacoleo'' to be the most specialised mammalian carnivore of all time. ''Thylacoleo'' had vertical shearing 'carnassial' cheek teeth that are relatively larger than in any other mammalian carnivore. ''Thylacoleo'' was clearly derived from the diprotodontian ancestry due to its incisor morphology and is distinguished by the pronounced development of upper and lower third premolars which functioned as extreme carnassials with complementary reduction in the molar teeth row. They also had canines but they served little purpose as they were stubby and not very sharp.

Behaviour and diet

Diet

When ''Thylacoleo'' was first described by Richard Owen, he considered it to be a carnivore, based on the morphology of its skull and teeth. However other anatomists, such as

William Henry Flower Sir William Henry Flower (30 November 18311 July 1899) was an English surgeon, museum curator and comparative anatomist, who became a leading authority on mammals and especially on the primate brain. He supported Thomas Henry Huxley in an impo ...

disagreed. Flower was the first to place ''Thylacoleo'' with the Diprotodonts, noting its skull and teeth to be laid out more like those of the koala and the wombat, and suggested that it was more likely a herbivore. Owen did not disagree with Flower's placement of ''Thylacoleo'' with the Diprotodonts, but still maintained that it was a carnivore, despite its herbivorous ancestry. Owen found little support in his lifetime, despite the pointing out of ''Thylacoleos retractable claws, something only found in mammalian carnivores, and its lack of any ability to chew plant material. In 1911, a study by Spencer and Walcott claimed that certain marks on the bones of megafauna had been made by ''Thylacoleo'', but according to Horton (1979) they were not sufficiently rigorous, resulting in their arguments being strongly challenged by later scholars, such as Anderson (1929), and later Gill (1951, 1952, 1954), thereby leaving the issue unresolved. In 1981, another paper was published arguing that certain cuts to bones of large marsupials had been caused by ''Thylacoleo''. This paper by Horton and Wright was able to counter earlier arguments that such marks were the result of humans, largely by pointing out the presence of similar marks on the opposite side of many bones. They concluded that humans were extremely unlikely to have made the marks in question, but that if so "they had set out to produce only marks consistent with what ''Thylacoleo'' would produce". Since then, the academic consensus has emerged that ''Thylacoleo'' was a predator and a hypercarnivore. Besides the most common hypothesis that it was an active predator, a variety of other theories existed in the late 19th to early 20th centuries as to the diet and feeding of ''Thylacoleo'', with hypotheses of it being a scavenger filling the ecological niche of hyenas, being a specialist of crocodile eggs, or even a melon-eater. As late as 1954, doubts were still being raised as to whether it was actually a hypercarnivore. The marsupial lion's limb proportions and muscle mass distribution indicate that, although it was a powerful animal, it was not a particularly fast runner. Paleontologists conjecture that it was an ambush predator, either sneaking up and then leaping upon its prey, or dropping down on it from overhanging tree branches. This is consistent with the depictions of the animal as striped: camouflage of that kind is needed for stalking and hiding in a largely forested habitat (like tigers) rather than chasing across open spaces (like lions). Trace fossils in the form of claw marks and bones from caves in Western Australia analyzed by Gavin Prideaux et al. indicate marsupial lions could also climb rock faces, and likely reared their young in such caves as a way of protecting them from potential predators. It is thought to have hunted large animals such as the enormous '' Diprotodon'' and giant browsing kangaroos like ''

Sthenurus ''Sthenurus'' ("strong tail") is an extinct genus of kangaroos. With a length around 3 m (10 ft), some species were twice as large as modern extant species. ''Sthenurus'' was related to the better-known ''Procoptodon''. The subfamily S ...

'' and ''

Procoptodon ''Procoptodon'' is an extinct genus of giant short-faced (sthenurine) kangaroos that lived in Australia during the Pleistocene Epoch. ''P. goliah'', the largest known kangaroo species that ever existed, stood at about . They weighed about . Other ...

'', and competed with other predatory animals such as the giant monitor lizard, '' Megalania'', and terrestrial crocodiles such as '' Quinkana''. The marsupial lion may have cached kills in trees in a manner similar to the modern

. Like many predators, it was probably also an opportunistic

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

, feeding on

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

and driving off less powerful predators from their kills. It also may have shared behaviours exhibited by recent diprotodont marsupials such as kangaroos, like digging shallow holes under trees to reduce body temperature during the day.

Senses

CT scans of a well-preserved skull have allowed scientists to study internal structures and create a brain endocast showing the surface features of the animal's brain. The parietal lobes, visual cortex, and olfactory bulbs of the cerebrum were enlarged, indicating the marsupial lion had good senses of hearing, sight, and smell, as might be expected of an active predator. Also, a pair of blind canals within the nasal cavity were probably associated with detecting pheromones as in the

Tasmanian devil The Tasmanian devil (''Sarcophilus harrisii'') (palawa kani: purinina) is a carnivorous marsupial of the family Dasyuridae. Until recently, it was only found on the island state of Tasmania, but it has been reintroduced to New South Wales in ...

. This indicates it most likely had seasonal mating habits and would "sniff out" a mate when in season.Thylacoleo "The Beast of the Nullarbor"
'' Catalyst'', Western Australian Museum, Storyteller Media Group and ABC TV, 17 August 2006.

Feeding

The feeding behaviour of ''Thylacoleo'' remains a topic of academic debate, largely due the lack of any living analogue. While considered a powerful hunter, and a fierce predator, it has been theorized that due to its physiology ''Thylacoleo'' was, in fact, a slow runner, limiting its ability to chase prey. Analysis of its scapula suggests "walking and trotting, rather than climbing ... the pelvis similarly agrees with that of ambulators and cursors alkers and runners. These bones indicate that ''Thylacoleo'' was a slow to medium-paced runner, which is likely to mean it was an ambush predator. That fits with the stripes: camouflage of the kind one would need for stalking and hiding in a largely forested habitat (like tigers or leopards) rather than chasing across open spaces (like lions)." It may have functioned generally much like a larger analog of the

. New evidence also suggests that it may have been arboreal, and was at the very least capable of climbing trees. Incisions on bones of ''Macropus titan'', and the general morphology of ''Thylacoleo'' suggests that it fed in a similar manner to modern cheetahs, by using their sharp teeth to slice open the ribcage of their prey, thereby accessing the internal organs. They may have killed by using their front claws as either stabbing weapons or as a way to grab their prey with strangulation or suffocation.

Palaeoecology

Numerous fossil discoveries indicate the marsupial lion was distributed across much of the

n continent. A large proportion of its environment would have been similar to the southern third of Australia today, semiarid, open

scrub Scrub(s) may refer to: * Scrub, low shrub and grass characteristic of scrubland * Scrubs (clothing), worn by medical staff * ''Scrubs'' (TV series), an American television program * Scrubs (occupation), also called "scrub tech," "scrub nurse," ...

and woodland punctuated by

waterhole A waterhole is a depression in the ground in which water can collect, or a more permanent pool in the bed of an ephemeral river. Waterhole or water hole may refer to: * Water hole (radio), an especially quiet region of the electromagnetic spect ...

s and water courses. It would have coexisted with many of the so-called Australian megafauna such as ''Diprotodon'', giant kangaroos, and ''Megalania'', as well as giant

wallabies A wallaby () is a small or middle-sized macropod native to Australia and New Guinea, with introduced populations in New Zealand, Hawaii, the United Kingdom and other countries. They belong to the same taxonomic family as kangaroos and so ...

like ''

Protemnodon ''Protemnodon'' is an extinct genus of megafaunal macropodids that existed in Australia, Tasmania, and New Guinea in the Pliocene and Pleistocene. It is also called the giant kangaroo. Taxonomy Recent analysis of mtDNA extracted from fossils ind ...

'', the giant wombat ''

Phascolonus ''Phascolonus'' was a genus of prehistoric Australian marsupials in the wombat family. The largest species, ''Phascolonus gigas'', weighed as much as 200 kg (450 lb). ''Phascolonus'' existed alongside an even larger marsupial, ''Diprotodon'' ...

'', the giant snake ''

Wonambi ''Wonambi'' is an extinct genus of madtsoiid snakes that lived in late Neogene to late Quaternary Australia. Species of ''Wonambi'' were constrictor snakes unrelated to Australian pythons. Description ''Wonambi'' was a fairly large snake, ...

'', and the thunderbird '' Genyornis''. ''T. hilli'' was a similar size to a contemporaneous thylacinid species, ''

Wakaleo alcootaensis ''Wakaleo alcootaensis'' was a species of marsupial lion of the genus ''Wakaleo'', that lived during the late Miocene, about 10 million years ago. Taxonomy The first description was given in an examination of material discovered at Alcoota in ...

'', and may have occupied habitat to the exclusion of that carnivore. Australia's Pleistocene megafauna would have been the prey for the agile ''T. carnifex'', who was especially adapted for hunting large animals, but was not particularly suited to catching smaller prey. The relatively quick reduction in the numbers of its primary food source around 40,000 to 50,000 years ago probably led to the decline and eventual extinction of the marsupial lion. The arrival of humans in Australia and the use of

fire-stick farming Fire-stick farming, also known as cultural burning and cool burning, is the practice of Aboriginal Australians regularly using fire to burn vegetation, which has been practised for thousands of years. There are a number of purposes for doing this ...

precipitated their decline. The extinction of ''T. carnifex'' makes

unique from the other continents because no substantial, apex mammalian predators have replaced the marsupial lions after their disappearance.

Extinction

It was believed that the extinction was due to the climate changes, but human activities as an extinction driver of the most recent species is possible yet unproven. There is a growing consensus that the extinction of the

megafauna In terrestrial zoology, the megafauna (from Greek μέγας ''megas'' "large" and New Latin ''fauna'' "animal life") comprises the large or giant animals of an area, habitat, or geological period, extinct and/or extant. The most common threshold ...

was caused by progressive drying starting about 700,000 years ago (700 ka). It is revealed recently that there was a major change in glacial-

interglacial An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene in ...

cycles after ~450 ka. As for human involvement's contribution to the extinction, one argument is that the arrival of humans was coincident with the disappearance of all the extinct megafauna. This is supported by the claims that during MIS3, climatic conditions are relatively stable and no major climate change would cause the mass extinction of megafauna including ''Thylacoleo''. Although believed to have been a victim of climate change, some scientists now believe ''Thylacoleo'' to have been exterminated by humans altering the ecosystem with fire in addition to hunting its prey. "They found ''Sporormiella'' spores, which grow in herbivore dung, virtually disappeared around 41,000 years ago, a time when no known climate transformation was taking place. At the same time, the incidence of fire increased, as shown by a steep rise in charcoal fragments. It appears that humans, who arrived in Australia around this time, hunted the megafauna to extinction". Following the extinction of ''T. carnifex'', no other apex mammalian predators have taken its place.

Discoveries

The first specimens of ''Thylacoleo'' were collected in the early 1830s from the Wellington Valley region of New South Wales by Major (later Sir) Thomas Mitchell, however they were not recognised as ''Thylacoleo'' at the time. The species was first described by

in 1859, from a fragmentary specimen discovered by William Adeney near Lake Colungolac, near Camperdown in Victoria In 2002, eight remarkably complete skeletons of ''T. carnifex'' were discovered in a limestone cave under Nullarbor Plain, where the animals fell through a narrow opening in the plain above. Based on the placement of their skeletons, at least some survived the fall, only to die of thirst and starvation. In 2008, rock art depicting what is thought to be a ''Thylacoleo'' was discovered on the northwestern coast of the Kimberley. However, there is the possibility that the thylacine, a related marsupial that also had a striped coat, may be the subject of the work, instead. The drawing represented only the second example of megafauna depicted by the indigenous inhabitants of Australia. The image contains details that would otherwise have remained only conjecture; the tail is depicted with a tufted tip, it has pointed ears rather than rounded, and the coat is striped. The prominence of the eye, a feature rarely shown in other animal images of the region, raises the possibility that the creature may have been a

nocturnal Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite. Nocturnal creatures generally have highly developed sens ...

hunter. In 2009, a second image was found that depicts a ''Thylacoleo'' interacting with a hunter who is in the act of spearing or fending the animal off with a multiple-barbed spear. Much smaller and less detailed than the 2008 find, it may depict a thylacine, but the comparative size indicates a ''Thylacoleo'' is more likely, meaning that it is possible that ''Thylacoleo'' was extant until more recently than previously thought. In 2016,

trace fossils A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils, ...

in Tight Entrance Cave were identified as being the scratch marks of a ''Thylacoleo''.

Fossils

The first ''Thylacoleo'' fossil findings, discovered by Thomas Mitchell were found in the 1830s in the Wellington Valley of New South Wales, though not recognised as such at the time. The generic holotype, consisting of broken teeth, jaws, and a skull was discovered by a pastoralist, William Avery, near Lake Colungolac from which the species ''Thylacoleo carnifex'' was described by

. It was not until 1966 that the first nearly-complete skeleton was found. The only pieces missing were a foot and the tail. Currently, the Nullarbor Plain of West Australia remains to be the greatest finding site. These fossils now reside at the Australian Museum. It was reported that in 2012, an accumulation of vertebrate trace and body fossils were found in the Victorian Volcanic Plains in south-eastern Australia. It was determined that ''Thylacoleo'' was the only taxon that represented three divergent fossil records: skeletal, footprints, and bite marks. What this suggests is that these large carnivores had behavioral characteristics that could have increased their likelihood of their presence being detected within a fossil fauna. A characteristic seen in the remains of skull fragments is a set of carnassial teeth, suggesting the carnivorous habits of ''Thylacoleo''. Tooth fossils of the thylacoleo exhibit specific degrees of erosion that are credited to the utility of the carnassial teeth remains as they were used for hunting and consuming prey in a prehistoric Australia teeming with other megafauna. The specialisation found in the dental history of the marsupial indicates its status in the predatory hierarchy in which it existed.

References

External links

New study finds no evidence for theory humans wiped out megafauna

''Thylacoleo'' in Pleistocene Australia

Western Australian Museum: ''Thylacoleo'' - a voracious hunter

PLEDGE. N 1977, A NEW SPECIES OF ''THYLACOLEO'' (MARSUPIALIA: THYLACOLEONIDAE) WITH NOTES ON THE OCCURRENCES AND DISTRIBUTION OF THYLACOLEONIDAE IN SOUTH AUSTRALIA
{{Taxonbar, from=Q312099 Prehistoric vombatiforms Prehistoric mammals of Australia Pliocene marsupials Pleistocene marsupials Pleistocene genus extinctions Carnivorous marsupials Prehistoric marsupial genera Taxa named by Richard Owen Fossil taxa described in 1859 Apex predators