The marsupial lions come in all sizes. Previous research suggests that some of the mammals were as small as squirrels, and researchers say a new species was the size of a dog.
A team from the University of New South Wales published an article 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 teeth, skull and humerus of the animal, researchers determined that the 50-pound climber wandered through the rainforests about 18 to 26 million years ago, during the late Oligocene and early Miocene. The predator the size of a dog had a flat head and large, razor-like teeth that could cut flesh and chew vegetation.
"The identification of these new species has brought to light a level of diversity of marsupial lions that was quite unexpected and suggest even deeper sources for the family," says lead author Anna Gillespie in a press release.
A march of progress of mammals
W. schouteni would have lived during the same time as Microleo attenboroughi, the lion of 1.3 pounds found in the fossil deposit of Neville's garden. M. attenboroughi was an omnivore the size of a squirrel that climbed trees in the rainforests of prehistoric Australia. The much larger W. schouteni was also arboreal.
This discovery contrasts with previous research that said there were no two species of marsupial lions at the same time.
"They would have existed at the same time, in fact, they know the same fossil in particular," says Christine Janis, a paleontologist who did not participate in the study. "They would have been very different in size and would have been different types of predators."
Prehistoric marsupial lions are closely related to modern koalas and wombats. Despite the name, they are not descendants of African lions; Researchers use "lion" to refer to the state of animals as dangerous carnivores. (Think of them as the "big cats" of prehistory.) All lions are omnivores, says Janis, but little by little they became more carnivorous and eventually overcame their tree-climbing ancestors. She compares them to a "rebellious opossum."
"We are filling in the hypothesis of what the lineage would have been like," says Janis.