<Li> Thylacinus communis Anon., 1859 </Li> <Li> Thylacinus breviceps Krefft, 1868 </Li> <P> The thylacine (/ ˈθaɪləsiːn / THY - lə - seen, or / ˈθaɪləsaɪn / THY - lə - syne, also / ˈθaɪləsɪn /; Thylacinus cynocephalus) was the largest known carnivorous marsupial of modern times . It is commonly known as the Tasmanian tiger (because of its striped lower back) or the Tasmanian wolf (because of its canid - like appearance, traits and attributes). Native to continental Australia, Tasmania, and New Guinea, it is believed to have become extinct in the 20th century . It was the last extant member of its family, Thylacinidae; specimens of other members of the family have been found in the fossil record dating back to the late Oligocene . </P> <P> Surviving evidence suggests that it was a relatively shy, nocturnal creature with the general appearance of a medium - to - large - size dog, except for its stiff tail and abdominal pouch (similar to a kangaroo) and dark transverse stripes that radiated from the top of its back, reminiscent of a tiger . The thylacine was an apex predator, like the tigers and wolves of the Northern Hemisphere from which it obtained two of its common names . As a marsupial, it was not closely related to these placental mammals, but because of convergent evolution it displayed a similar general form and adaptations . Its closest living relative is thought to be either the Tasmanian devil or the numbat . The thylacine was one of only two marsupials to have a pouch in both sexes (the other being the water opossum). The male thylacine had a pouch that presumably acted as a protective sheath, covering his external reproductive organs while he ran through thick brush . The thylacine has been described as a formidable predator . </P>

When did the last tasmanian tiger go extinct