Very generally the tail has distinctly the appearance of an appendage, but in some of the lower mammals, such as the thylacine among marsupials, and the aard-vark or ant-bear among the edentates, it is much thickened at the root, and passes insensibly into the body, after the fashion common among reptiles.
That it was not much earlier is shown by the fact that some still living species of mammals, such as the thylacine, existed before"the separation.
Julia Leigh, author of The Hunter, writes Back from the dead, on the hype surrounding plans to clone the extinct thylacine.
For instance, according to the older view, the dental formula in the thylacine or Tasmanian wolf is i., c, i, p. 3, m.
The largest representative of the family is the Tasmanian wolf,' or thylacine, alone representing the genus Thylacinus, in which the dentition numbers i.