Marsupial lions come in all sizes. Previous research suggests some of the mammals were as small as squirrels, and researchers today are saying a new species was dog-sized.
A team at the University of New South Wales published a paper in the Journal of Systematic Palaeontology on December 6 describing Wakaleo schouteni, a prehistoric species of marsupial lion. By studying the fossilized remains of the animal's teeth, skull, and humerus, the researchers determined the 50-pound climber roamed rainforests about 18 to 26 million years ago, during the late Oligocene and early Miocene eras. The predator ranged from dog-size to leopard-size, and had a short head and large, blade-like teeth that could slice through flesh and munch on vegetation.
"The identification of these new species has brought to light a level of marsupial lion diversity that was quite unexpected and suggest even deeper origins for the family," lead author Anna Gillespie says in a press release.
A Mammalian March of Progress
W. schouteni would have lived during the same time as the Microleo attenboroughi, the 1.3-pound micro lion found in the Neville's Garden fossil deposit. M. attenboroughi was a squirrel-sized omnivore that climbed trees in the rainforests of prehistoric Australia. The much-larger W. schouteni was also arboreal.
"They would have been around at the same time. They're actually known from the same particular fossil site," says Christine Janis, a paleontologist who was not involved in the study. "They would have been very different in size and so would have been different kinds of predators."
W. schouteni adds to the evolving narrative of marsupial lions, which had a bite more powerful than any modern lion. The family, whose members grew in size throughout history, also includes the "pouched lion executioner" Thylacoleo carnifex.
Prehistoric marsupial lions are related to modern koalas and wombats. Despite the name, they're not descendants of African lions; researchers use "lion" to refer to the animals' status as dangerous carnivores. (Think of them as the "big cats" of prehistory.) All of the lions started out as are omnivores, Janis says, but they gradually became more carnivorous and outgrew their tree-climbing ancestors over time. She likens them to a "rogue possum."
"We're filling in what the hypothesis sort of was on what the ancestry would have been like," Janis says.
A previous version of this story misidentified a carniverous marsupial species that was not a part of the marsupial lion family. It also incorrectly stated all marsupial lions were omnivores. This story has been updated with information from the researchers.