Thylacoleonidae is a family of extinct carnivore marsupials from Australia, referred to as marsupial lions.
Description
notable distinctive feature of thylacoleonids is their unusual blade-like third
,
which functioned as the
carnassial teeth.
Thylacoleonids varied widely in body size. One of the smallest thylacoleonids, the Early Miocene
Microleo attenboroughi, is estimated to have had a body mass of , while the last species of the family, the Pleistocene
Thylacoleo carnifex is suggested to have had a body mass of around , comparable to a
big cat.
Later members of the group saw progressive reduction in the number of teeth in the jaws.
Ecology
Early members of Thylacoleonidae like
Microleo, Lekaneleo and early species of
Wakaleo were likely
arboreal tree climbing mammals, though later members of
Wakaleo and
Thylacoleo were likely primarily terrestrial with some climbing capabilities.
Some early species of Thylacoleonidae like
Lekaneleo roskellyae are suggested to have been
omnivorous, with others like
Microleo were likely carnivorous, feeding on small vertebrates and (to a probably small extent) insects.
Species of
Wakaleo and
Thylacoleo are thought to have been
hypercarnivores that fed on larger prey.
Taxonomy
Thylacoleontidae is considered a member of
Diprotodontia, though its precise position within that group is uncertain. They have often been considered a basal group (often the most basal group) within
Vombatiformes, making their closest living relatives wombats and koalas,
though other authors have placed them at the base of Diprotodontia, outside of either Vombatiformes,
Phalangeriformes or
Macropodiformes.
Thylacoleonids are thought to have evolved from herbivorous ancestors.
The family was described by Theodore Gill in a systematic revision of mammalian taxa published by the Smithsonian Institution in 1872.
A revision of the family was published in 2017, enabled by the discovery of a skull of an early species, named as Wakaleo schouteni, which allowed closer comparison with previously described species and the more complete fossil record of the lineages. The study by Anna Gillespie, Mike Archer and Suzanne Hand, revised the description of Wakaleo to include a new species and circumscribe taxa previously assigned to Priscileo.
Classification
Five genera are currently accepted as belonging to this family:
Cladogram after Gillespie (2023):
