Eighty-eight years ago today, the last known Tasmanian tiger died, leaving humankind to reflect on its role in the species’ erasure. Now, a team of researchers has announced the discovery of the thylacine’s earliest-known ancestors: heavy-metal marsupials with jawbones so tough the animals could eat bones and teeth.
The team’s research, published today in the Journal of Vertebrate Paleontology, describes several marsupials that lived in Australia during the late Oligocene, about 24 million years ago. The marsupials were ancestors of the Tasmanian tiger, or thylacine, a creature that resembled a dog save for the distinctive, eponymous black stripes on its back. The thylacine was capable of opening its jaw remarkably wide and typically fed on marsupials and small rodents. It was driven to extinction by factors including habitat loss and overhunting, after the Tasmanian government put a bounty on the animal’s head when seen as a threat to livestock.
The recent paper describes some of the thylacine’s ancient ancestors, which were smaller than the modern animal, which until its extinction was the largest extant carnivorous marsupial.
“The once suggested idea that Australia was dominated by reptilian carnivores during these 25 million-year-long intervals is steadily being dismantled as the fossil record of marsupial carnivores, such as these new thylacinids, increases with each new discovery,” said Timothy Churchill, a researcher at the University of New South Wales and the study’s lead author, in a Taylor & Francis release.
The three newly dubbed marsupial ancestors are B. timfaulkneri, Nimbacinus peterbridgei, and Ngamalacinus nigelmarveni. They were found in the Riversleigh World Heritage Area, which contains the richest deposit of fossil mammals in Australia. According to the Australian Museum, the thylacines disappeared from the Australian mainland no later than 2,000 years ago.
B. timfaulkneri is the oldest thylacine known to date and was the largest of the three, weighing between 15 and 24 pounds (7 and 11 kilograms). Of the three fossils, N. peterbridgei appeared more closely related to the Tasmanian tiger than the other fossil ancestors, leading the team to conclude it’s probably the oldest direct ancestor of the recently extinct carnivore.
The now-extinct animals exhibited “very different dental adaptations, suggesting there were several unique carnivorous niches available during this period,” said study co-author Michael Archer, a paleontologist at UNSW, in the same release. “All but one of these lineages, the one that led to the modern Thylacine, became extinct around 8 million years ago.”
The last known thylacine died in a zoo in 1936, though some researchers suggest the animal more likely went extinct sometime in the 1960s. The thylacine is now a hot topic because a biosciences company claims it intends to resurrect a proxy thylacine—that is, an animal built on the thylacine genome which could occupy the same environmental niche as the lost marsupial.
De-extinction, as it’s called, is much easier said than done, though last year a team was successful in recovering RNA from the animal, the first time the molecule has been recovered from an extinct species. Until then, we can appreciate the bonafide thylacinids of yesteryear—which is to say, the Oligocene.
