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Presented on this and following three pages are some of the thylacines
which existed prior to the modern species,
T. cynocephalus.
The history of the family Thylacinidae stretches far back into the Tertiary
Period, and thylacines of many shapes and sizes have evolved since at least
Late Oligocene times. T. cynocephalus is the last remaining
member of this ancient lineage.
Thylacinus potens:
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I will begin my discussion of Tertiary thylacinids with T. potens,
as this is among the more frequently mentioned of the fossil species, and
belongs to the same genus as the modern thylacine.
Thylacinus potens,
whose name means "powerful thylacine", is the largest thylacinid species
known to have existed. |
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| A
life reconstruction of Thylacinus potens (based upon an illustration
by Anne Musser). Note that the body build is somewhat more massive
than that of T. cynocephalus. The pattern of the stripes is
purely speculative - as is the case with other fossil species known only
from their bones, we can only theorize about their coat patterns based
upon living species. |
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Preceding T. cynocephalus
by about 4-6 million years, its remains are known only from a single Late
Miocene locality near Alice Springs, Northern Territory. This thylacine
had a considerably more massive build than the modern species, and had
a somewhat shorter, broader skull. Its teeth also show some slight
differences in morphology, and appear to be not quite as specialized for
shearing as those of T. cynocephalus (Archer 1983).
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| Another
reconstruction of T. potens (based upon an illustration by Peter
Schouten). Again, the form of the animal's markings are hypothetical. |
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Woodburne
(1967) states that T. potens is quite similar to thylacines of Quaternary
(our current geological time period) age, but in its possession of "...small
palatal fenestrae, the presence of a stylar cusp anterior to the metastyle
of M3, the more symmetrical arrangement of the parts of the upper molars
and the strong cleft in the labial outline of the upper molars...", these
character states in the Miocene species "...could be interpreted
as primitive features relative to a remote dasyurid ancestry." |
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Material: Woodburne (1967) has given a comprehensive description
of the holotype
specimen, a poorly preserved rostrum including a palate and damaged dentition.
The fossil was found at Paine Quarry, Alcoota Homestead, in the Northern
Territory. Some dentary fragments also exist (University of California,
Berkeley, paleontological collections), but these are far less complete
than the rostrum. A few additional mandibular fragments and a small
section of the premolar region of a maxilla of a second skull were found
on a subsequent visit to Alcoota in 1975 (the Ray E. Lemley Expedition
to Alcoota). These new specimens (Queensland Museum) however, add
little to the concept of the species as known by Woodburne (1967).
Age: The
Alcoota Local Fauna, from the Waite Formation, is interpreted to be of
Late Miocene age (approx. 7 million years old). This fauna is dated
on the basis of comparison with other dated faunas. On this basis,
it is older than the Early Pliocene local faunas, such as the Chinchilla,
Bluff Downs, Bow and Hamilton faunas but younger than the array of Middle
Miocene local faunas such as the Tarkarooloo, Pinpa, Ngapakaldi and Ericmas
faunas (dated at around 15 million years old). As of yet however,
there is no means of establishing an absolute date for the Alcoota Local
Fauna. |
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| A
palatal view of the holotype specimen of
Thylacinus potens Woodburne
(Archer 1982). The dentition
of this rostrum is in quite poor condition, but it is a spectacular and
very rare fossil nonetheless, and is of extreme significance in our understanding
of ancient thylacines. |
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