| The history of the
family Thylacinidae stretches far back into the Tertiary Period, and thylacine
species of many shapes and sizes have evolved since at least Late Oligocene
times. The modern species, T. cynocephalus, is the last remaining
member of this ancient lineage.
Badjcinus turnbulli:
This Late Oligocene
thylacine was found at Riversleigh (White Hunter Site, White Hunter Local
Fauna). Its species name honors Bill Turnbull, who has contributed
much to the study of fossil mammals. |
.
.
| Some
examples of Badjcinus turnbulli fossils (images not shown at relative
size to each other). Top - right dentary fragment containing P2-3
and M1-3. Bottom - left portion of dentary containing P2, M1-4, and
alveoli (sockets) for i(3), C, P1 and P3. (Muirhead and Wroe 1998). |
|
The genus
was described on the basis of a partial skull and nearly complete upper
and lower jaws. B. turnbulli appears to be one of the oldest
and most primitive types of thylacine yet known. Muirhead and Wroe
(1998) consider small thylacines such as Badjcinus
to be approximately the same size as the larger living dasyurids (e.g.
Dasyurus
maculatus), and probably had similar ways of life, preying
upon insects, reptiles and small mammals. |
.
| Maximucinus muirheadae:
M. muirheadae
is from the Middle Miocene. The holotype and only known specimen
is a second upper molar (M2), found at Riversleigh (Ringtail Site, Ringtail
Local Fauna). |
.
|
Its species name honors Jeanette Muirhead for her work on fossil thylacinids.
It is the largest thylacine species known from Australia's Late Oligocene
to Middle Miocene deposits, and is estimated by Wroe (2001)
to have been about the same size as a small T. cynocephalus.
In its dental morphology, it appears to be less specialized
than species of Thylacinus,
Wabulacinus and Tyarrpecinus. |
.
| The
holotype specimen (an M2 tooth) of Maximucinus muirheadae. A,
occlusal view. B, lateral view. C, lingual view. (Wroe
2001). |
|
.
| Muribacinus gadiyuli:
This is another thylacine
species of Middle Miocene age from Riversleigh (System C localities - e.g.
Gag and Henk's Hollow Sites, Dwornamor and Henk's Hollow Local Faunas).
M.
gadiyuli's specific name comes from an Waanyi Aboriginal word meaning
"little", in reference to the fact that this species was considerably smaller
than the modern thylacine. M. gadiyuli is known from a well
preserved right maxilla and section of the jugal bone (holotype), and a
right dentary (paratype).
It is the most primitive member of the family Thylacinidae yet known, and
was approximately the size of a fox-terrier dog.
Mutpuracinus archibaldi:
M. archibaldi
was discovered in the Middle Miocene deposits at Bullock Creek (Blast Site,
Bullock Creek Local Fauna) in the Northern Territory, and named in honor
of Ian Archibald for his contributions to the natural history of the Northern
Territory. The holotype specimen is a left maxilla containing P2-3
and M1-4. |
.
.
| A
close-up occlusal view of molars M2-3 in the holotype maxilla of M.
archibaldi. (Murray and Megirian 2000). |
|
Other known
fossils of the species include a premaxilla with alveoli (sockets) for
four incisors, and a dentary fragment bearing M3-4. Of the ancient
thylacinids yet discovered, M. archibaldi is the smallest, and was
about the same size as a modern quoll (Dasyurus sp.). Mutpuracinus
is also a plesiomorphic
taxon, considered to be only somewhat more derived in its dental
characteristics than Muribacinus gadiyuli. M. archibaldi
was found in the same deposit as the larger
Nimbacinus richi, with
which it was contemporary. |
Ngamalacinus timmulvaneyi:
This Early Miocene species
was found at Riversleigh (Inabeyance Site, Inabeyance Local Fauna; also
Camel Sputum Local Fauna). Its species name honors Tim Mulvaney.
This species is more plesiomorphic than Wabulacinus or Thylacinus,
but more derived than
Nimbacinus or Muribacinus. Overall,
it most closely resembles Wabulacinus, but is the sister group to
a combined
Wabulacinus/Thylacinus clade.
Like Wabulacinus, Ngamalacinus was a small, dog-sized thylacine
that was contemporary with at least two other small thylacinid species.
It is assumed that each type was independently specialized to pursue certain
kinds of prey in the Early Miocene rainforest of Queensland. |
