Australia: The Land Where Time Began

A biography of the Australian continent 

Riversleigh Thylacinids        see Thylacinidae

At least 5 different thylacines have been found in the Oligocene-Miocene deposits at Riversleigh. The range in size among the Riversleigh thylacines is from the size of a domestic cat to the a bit smaller than a German Sheppard. The smallest was not much smaller than the largest of the dasyurids from Riversleigh, the largest was bigger than any known dasyurid.

Nimbacinus dicksoni is very primitive, lacking the distinctive features of thylacines, such as a distinct metaconid on its lower molars,  from deposits other than Riversleigh. A jaw has been found at Bullock Creek in the Northern Territory. Some of the thylacines from Riversleigh are very primitive, looking nearly as much like primitive dasyurids as other thylacines, adding to the evidence that thylacines are most closely related to the dasyurids. The smallest of the thylacines, among others, are almost as specialised as T. cynocephalus, indicating that the line is much older than those found at Riversleigh.

When thylacines first appear in the fossil record of Riversleigh, about 20 million years ago, there were 5 species in 2 genera, differing in size and shape. By 15 million years ago 2 of these species were left. By the time of Alcoota, 8 million years ago, only one of the species was left. By the Late Holocene the last species was extinct on the mainland and New Guinea.

Sources & Further reading

Michael Archer, Suzanne J. Hand & Henk Godthelp, Australia's Lost World: Riversleigh, world heritage Site, Reed New Holland

Links

• The Natural History of the Thylacinus cynocephalus
• Murra-el-Elevyn Cave
• Nimbacinus dicksoni

Sources & Further reading

• Michael Archer, Suzanne J. Hand & Henk Godthelp, Australia's Lost World: Riversleigh, world heritage Site, Reed New Holland