A new study from Museums Victoria and the University of Melbourne has for the first time, showed how the Tassie Tiger evolved to look more like a dingo than a marsupial.
Researchers CT scanned all 13 Tassie Tiger joeys, creating 3D digital models allowing them to understand and study how their skeletons and internal organs grow and develop.
Surprisingly the digital scans revealed that when the Thylacine or Tassie Tiger is first born they looked like any other marsupial, however, three months later, when they had left the pouch their appearance is more similar to that of a puppy, continuing to grow with a dog-like appearance.
The Tassie Tiger’s “dingo” like appearance is best explained as “convergent evolution.” When two species, despite not being at all related, evolve to look very similar.
According to the study, the Tasmanian Tiger would have shared a common ancestor with canids (dogs and wolves) around 160 million years ago.
Dr Christy Hipsley a research associate from Museums Victoria explained that after sequencing the thylacine genome, researchers have come closer to understanding why the marsupial evolved to resemble dingoes.
“This is the first digital development series of the Tasmanian tiger, Australia’s most iconic extinct marsupial predator. Using CT technology we have been able to garner new information on the biology of this iconic species, and its growth and development,” she explains.
“These scans show in incredible detail how the Tasmanian tiger started its journey in life as a joey that looked very much like any other marsupial, with robust forearms so that it could climb into its mother's pouch. But by the time it left the pouch around 12 weeks to start independent life, it looked more like a dog or wolf, with longer hind limbs than forelimbs.”
The thylacine or the Tassie tiger once roamed Australia and New Guinea, disappearing from the mainland around 3,000 years ago. It is thought this was due to competition with humans and dingos. The remaining population in Tasmania was hunted to extinction in the early 20th century. The last of its kind ding in captivity in 1936.
Axel Newton, PhD student notes:
“Until now, there have only been limited details on its growth and development. For the very first time, we have been able to look inside these remarkably rare and precious specimens.”
As the team no longer had access to the living species they examined 13 Tasmanian Tiger joey specimens that exist in Museum collections all over the world. The specimens, representing five stages of postnatal development, were then scanned using non-invasive X-ray micro CT scanning technology to create high-resolution 3D digital models, where their organs and skeletons could be studied.
Andrew Pask, Associate Professor at the University of Melbourne believes this technique was incredibly effective, to study the animals without harming the specimens.
This research clearly demonstrates the power of CT technology. It has allowed us to scan all the known Thylacine joey specimens in the world, and study their internal structures in high resolution without having to dissect or cause damage to the specimen.”
“By examining their bone development, we’ve been able to illustrate how the Tasmanian tiger matured and identify when they took on the appearance of a dog.”
Three dimensional digital Tasmanian Tiger models will be made public for current and future researchers.
Lead image: 3D digital render of Tasmanian tiger joey, The University of Melbourne