Paleontologists have discovered a new species of carnivorous marsupial lion that lived 26 to 18 million years ago (late Oligocene to early Miocene) in the rainforests of Australia.
The newly discovered marsupial lion, called Wakaleo schouteni was the size of a dog and weighed about 23 kg.
The species was approximately one fifth of the weight of the largest and last surviving marsupial lion, Thylacoleo carnifex which weighed 130 kg and which has been extinct for 30,000 years.
"The identification of this species has brought to light a level of marsupial lion diversity that was quite unexpected and suggests even deeper origins for the Thylacoleonidae family," said Dr. Anna Gillespie, a paleontologist at the University of New South Wales, Australia.
The fossilized remains of Wakaleo schouteni – an almost complete skull, teeth and humerus (upper arm bone) – were found in Riversleigh, a World Heritage Site in remote northwest Queensland.
"With the new finding, we believe that two different species of marsupial lions were present in the late Oligocene at least 25 million years ago," paleontologists said.
"The other, originally called Priscileo pitikantensis but renamed Wakaleo pitikantensis was a little smaller and identified tooth and limb bones discovered near Lake Pitikanta in South Australia in 1961. "
The new species exhibits many cranial and dental features of the genus Wakaleo but also shared several similarities with Priscileo pitikantensis – particularly the presence of three upper premolars and four molars, previously the diagnostic feature of Priscileo .
Other similarities of the teeth and the humerus that are shared with Wakaleo schouteni indicate that Priscileo pitikantensis is a species of Wakaleo .
"These dental similarities distinguish Wakaleo schouteni and Priscileo pitikantensis from later species of this genus, all of which show premolar and molar reduction, and suggest that they are the most primitive members. of the genus. "
" This latest finding raises new questions about the evolution of marsupial lion relationships, "Dr. Gillespie concluded.
The team's findings are published in Journal of Systematic Palaeontology .
Anna K Gillespie et al. . A new oligo-Miocene marsupial lion from Australia and a review of the Thylacoleonidae family. Journal of Systematic Palaeontology published online on December 6, 2017; doi: 10.1080 / 14772019.2017.1391885