Life Tech New 3D images of Tasmanian tigers reveal evolutionary secrets
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New 3D images of Tasmanian tigers reveal evolutionary secrets

Internal structures of Thylacine joeys
The images allow researchers to study their development without destroying specimens. Photo: University of Melbourne
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Melbourne researchers have used Tasmanian tiger specimens more than a century old to create new 3D digital models, unlocking mysteries of the marsupial’s development before it was hunted to extinction.

Researchers say it’s the first time a series of wholly-preserved specimens of an extinct species has been digitally scanned, creating a unique timeline of early development from joeys aged just a few days old to fully-grown juveniles.

They have digitally scanned all known preserved specimens to show how it grew to look more like a dingo than a marsupial.

Scientists from the Melbourne Museum and the University of Melbourne hope that by using the models and the recently-mapped genome of the Tasmanian Tiger, or Thylacine, they will better understand how it evolved to look more like a dingo than a marsupial.

“This kind of technology is letting us see into the past … it’s huge to be able to look inside the development of an animal that’s extinct,” said researcher Dr Christy Hipsley.

“These specimens [are] extremely rare and valuable, so we can reconstruct the skeleton in three dimensions without damaging them.”

Eleven specimens from across Australia and overseas were scanned to create 3D models of the skeletons and internal organs of Tasmanian tiger joeys.

The images have revealed how at birth, the species displayed the typical marsupial characteristic of overly strong forelimbs to crawl from the mother’s birth canal into her pouch, but by five weeks of age their hind legs developed to look more like a dingo.

“We’ll use this in conjunction with the [Tasmanian tiger] genome that we’ve recently sequenced and this together allows us to pin-point the kinds of genes and developmental mechanisms that make an animal like a marsupial evolve to look a lot like a wolf or a dingo,” she said.

Dr Christy Hiplsey
Dr Christy Hiplsey says the research helps explain why Thylacines evolved to look similar to dogs. Photo: Museum Victoria

Researchers intrigued by ‘convergent evolution’

“They shared a common ancestor the last time in the Triassic period, so about 160 million years ago, so the fact they’ve overcome that amount of time to look almost indistinguishable is one of the best examples we have of convergent evolution,” Dr Hipsley said.

Tasmanian tigers were hunted to extinction in the early 20th century, with the last known individual dying at Hobart Zoo in 1936.

The new digital scanning process also revealed that two other preserved specimens, originally believed to be Tasmanian tigers, were actually most likely young quolls or Tasmanian devils.

Dr Hispley says the technology is being used more frequently by museums to verify species, and to reconstruct animals’ anatomy in great detail while leaving specimens and fossils intact.

Historic photo of Thylacines in 1912
Researchers say the Tasmanian tiger would have shared a common ancestor with dogs and wolves around 160 million years ago. Photo: Tasmanian Museum and Art Gallery

-ABC