Thylacoleonidae is a

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideall ...

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 ...

meat-eating 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 ...

marsupials from Australia, referred to as marsupial lions. The best known is ''

Thylacoleo carnifex ''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pre ...

'', also called the marsupial lion. The clade ranged from 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 ...

to the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in ...

, with some species the size of a possum and others as large as that of a leopard. As a whole, they were largely arboreal, in contrast to the mostly terrestrial

dasyuromorphs Dasyuromorphia (, meaning "hairy tail" in Greek) is an order comprising most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the thylacine. In Australia, the exceptions include the om ...

(

quolls Quolls (; genus ''Dasyurus'') are carnivorous marsupials native to Australia and New Guinea. They are primarily nocturnal and spend most of the day in a den. Of the six species of quoll, four are found in Australia and two in New Guinea. Anoth ...

only recently took the niches vacated by small thylacoleonids),

monitor lizards Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recogn ...

and mekosuchines. Hypercarnivory was also found in another order of marsupials, the

dasyuromorph Dasyuromorphia (, meaning "hairy tail" in Greek) is an order comprising most of the Australian carnivorous marsupials, including quolls, dunnarts, the numbat, the Tasmanian devil, and the thylacine. In Australia, the exceptions include the om ...

family

Thylacinidae Thylacinidae is an extinct family of carnivorous, superficially dog-like marsupials from the order Dasyuromorphia. The only species to survive into modern times was the thylacine (''Thylacinus cynocephalus''), which became extinct in 1936. ...

that included the Tasmanian tiger ''

Thylacinus cynocephalus The thylacine ( , or , also ) (''Thylacinus cynocephalus'') is an extinct carnivorous marsupial that was native to the Australian mainland and the islands of Tasmania and New Guinea. The last known live animal was captured in 1930 in Tasman ...

'' that became extinct in the twentieth century.

Description

Figure 18 in Researches on fossil mammals Australia Owen

diprotodontia Diprotodontia (, from Greek "two forward teeth") is the largest extant order of marsupials, with about 155 species, including the kangaroos, wallabies, possums, koala, wombats, and many others. Extinct diprotodonts include the hippopotamus-siz ...

n family allied to the

Vombatiformes The Vombatiformes are one of the three suborders of the large marsupial order Diprotodontia. Seven of the nine known families within this suborder are extinct; only the families Phascolarctidae, with the koala, and Vombatidae, with three extant ...

, mammals that radiated and diversified in the

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" ...

. The thylacoleonid genera exhibit specialised dentition that allowed them to kill prey larger than themselves. The earliest descriptions of the most recent species recognise the secateur-like blades of the teeth as a powerful mammalian predator, a "marsupial lion," that were noted as missing in the Australian environment. The third premolars exhibit this blade-like development, becoming greatly enlarged in the Pleistocene species ''

'', prompting the description by Owen as "…one of the fellest and most destructive of predatory beasts." They are seen as presumably occupying a trophic level as peak predators in their local ecologies, some smaller and arboreal climbers while those terrestrial species are sizably comparable to large dog or a big cat.

Distribution and habitat

The genera are associated with the late Oligocene and Miocene epochs. ''Microleo'' and ''Wakaleo'' have been located at the Lake Pitikanta fossil area in

Central Australia Central Australia, also sometimes referred to as the Red Centre, is an inexactly defined region associated with the geographic centre of Australia. In its narrowest sense it describes a region that is limited to the town of Alice Springs and ...

and toward the northern coast at Riversleigh, below the gulf of Carpentaria, a rich source of fossil fauna. The most recent species, ''Thylacoleo carnifex'', existed at least until the

, the earliest known specimens of the family are dated to around twenty five million years ago.

Taxonomy

The family was described by

Theodore Gill Theodore Nicholas Gill (March 21, 1837 – September 25, 1914) was an American ichthyologist, mammalogist, malacologist and librarian. Career Born and educated in New York City under private tutors, Gill early showed interest in natural histor ...

in a systematic revision of mammalian taxa published by the

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded o ...

in 1872. The name is derived from the genus named by Richard Owen, ''

Thylacoleo ''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pred ...

'', which he recognised as a potent carnivore and described as marsupial version of the modern lions (''Leo''). They are now thought to be allied with the

, still represented in the modern Australian fauna by koalas and wombats. They appear to have diverged by specialising in a carnivorous diet in the early Oligocene, and increased in size along with their prey during the Miocene. A revision of the family was published in 2017, enabled by the discovery of a skull of an early species, named as ''

Wakaleo schouteni ''Wakaleo schouteni'' is a species of carnivorous marsupial that was discovered at fossil sites in South Australia. Taxonomy The description of the species was published in 2017, the collaborating authors Anna Gillespie, Mike Archer and Suzanne ...

'', which allowed closer comparison with previously described species and the more complete fossil record of the lineages. The study by

Anna Gillespie Anna may refer to: People Surname and given name * Anna (name) Mononym * Anna the Prophetess, in the Gospel of Luke * Anna (wife of Artabasdos) (fl. 715–773) * Anna (daughter of Boris I) (9th–10th century) * Anna (Anisia) (fl. 1218 to 1221 ...

, Mike Archer and

Suzanne Hand Suzanne J. Hand (born 1955) is an associate professor at the University of New South Wales, a teacher of geology and biology, who has a special interest in vertebrate palaeontology Paleontology (), also spelled palaeontology or palæontology ...

, revised the description of ''Wakaleo'' to include a new species and circumscribe taxa previously assigned to '' Priscileo''.

Classification

Four genera are currently accepted as belonging to this family: *''Incertae sedis'' ::* '' Lekaneleo roskellyae''

Riversleigh fauna Riversleigh fauna is the collective term for any species of animal identified in fossil sites located in the Riversleigh World Heritage Area. Faunal zones The presence of the Riversleigh in the Oligo-Miocene has been exceptionally well preserved ...

, Early Miocene :*Genus '' Microleo'' ::* ''

Microleo attenboroughi ''Microleo attenboroughi'' is a very small species of the Thylacoleonidae family of marsupials from the Early Miocene of Australia, living in the wet forest that dominated Riversleigh about 18 million years ago. The genus ''Microleo'' is curre ...

'' (Early Miocene) *Subfamily Wakaleoninae :*Genus '' Wakaleo'' ::* ''

Wakaleo pitikantensis ''Wakaleo pitikantensis'' is a species of carnivorous marsupial that was discovered at fossil sites in South Australia. Taxonomy The description by Rauscher was published in 1987, naming a new species and genus as ''Priscileo pitikantensis''. ...

'' ( Upper Oligocene) ::* ''

'' (Upper Oligocene—Lower Miocene) ::* '' Wakaleo oldfieldi'' (Lower Miocene—Upper Miocene) ::* '' Wakaleo vanderleuri'' (Middle Miocene—Upper Miocene) ::* '' Wakaleo alcootaensis'' (Upper Miocene) *Subfamily Thylacoleoninae :*Genus ''

'' ::* ''

Thylacoleo crassidentatus ''Thylacoleo'' ("pouch lion") is an extinct genus of carnivorous marsupials that lived in Australia from the late Pliocene to the late Pleistocene (2 million to 46 thousand years ago). Some of these marsupial lions were the largest mammalian pre ...

'' (

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Thylacoleo hilli'' (Pliocene) ::* ''

'' (

)

References

Prehistoric vombatiforms Carnivorous marsupials Prehistoric mammals of Australia Chattian first appearances Pleistocene extinctions Prehistoric mammal families {{Diprotodont-stub