T. cynocephalus material is also known from Papua New Guinea.  A section of a thylacine mandible was excavated by Susan Bulmer at Kiowa, in the Eastern Highlands (Van Deusen 1963).
 

. The Mundrabilla thylacine mummy as it appeared when found on the floor of Thylacine Hole cave.

The most spectacular discovery yet was made in October 1966 at Thylacine Hole on Mundrabilla Station, 110 km west of Eucla, Western Australia (Lowry and Lowry 1966).  An almost vertical shaft 11½ metres (37.7 ft.) deep opened into a broad cave which was littered with the remains of native species.  Innumerable animals had plummeted down the shaft to their doom, becoming mummified in the cave's atmosphere, which in the main chamber registered a temperature of only 19°C (66.2°F) and a relative humidity of 67%.

The odour emanating from dead animals within the cave apparently acted as a lure for carnivores, which occasionally became trapped as well.  However, their bones were far fewer in number than those of the herbivorous species.  A completely intact mummy of a thylacine was found lying 140 metres (approx. 459 ft.) from the cave's entrance.  Most of the soft tissue had deteriorated into a thick, tarry substance bearing a musty odour.   However, the tongue and left eye were still reasonably intact.  The hair and skin were very well preserved, and even the stripes were still clearly visible.

. A close-up of the mummy's face.  For a naturally mummified specimen, the level of preservation is remarkable.

. The restored Mundrabilla mummy at the Western Australian Museum.  As can be seen here, the stripes are still plainly visible.  The tail, which was found separated from the body upon discovery, was likely removed by scavenging rats.

At first, it was hoped that the specimen had died only recently.  However, three separate radiocarbon tests have determined that the mummy is between 4,600-4,700 years old (Lowry and Merrilees 1969, Merrilees 1970).  There are many other unexamined caves on the Nullarbor which could possibly contain similar remains.

    I could speak at length about the studies which have been performed in regard to verifying the taxonomy of fossil thylacine material of Quaternary age.  However, apart from the aspect of historical interest, this would prove rather unnecessary at this point, as it has been well established that all such specimens, as of yet known, can firmly be considered to belong to the modern species, T. cynocephalus.

    Scientific names as T. breviceps, T. major, T. rostralis and T. spelaeus were used during the nineteenth century to describe various examples of Quaternary thylacine specimens from a number of different localities.  However, such names are no longer applied, as studies of said remains have been unable to find any morphological distinctions which are significant enough to warrant separate classifications.  A variability in size can be seen among specimens of Pleistocene and Holocene age from various localities, with some being either somewhat larger or smaller than the average modern T. cynocephalus, but these size differences alone are not considered a solid basis for making taxonomic distinctions.  The size variations could merely be due factors such as sexual dimorphism, or the particular environmental conditions under which the animals lived.