Tiny marsupial lion named after Sir David Attenborough

By AG Staff Writer 24 August 2016
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Researchers have uncovered fossil remains of an extinct flesh-eating marsupial lion that weighed about 600g and lived in the tree-tops.

THE FOSSIL REMAINS of a new, tiny species of extinct marsupial lion have been unearthed in north-western Queensland.

The new species, which would have prowled the lush rainforests of northern Australia about 18 million years ago, has been named Microleo attenboroughi both for its small size and to honour famous broadcaster and naturalist Sir David Attenborough, in recognition of his support for the Riversleigh World Heritage Area where the fossils were discovered. Attenborough has called the site one of the four most important fossil areas in the world.

The new species was much smaller than other members of this extinct marsupial lion family, with the biggest (Thylacoleo carnifex) growing up to 160kg. “Microleo attenboroughi would have been more like the cute, but still feisty kitten of the family,” said Dr Anna Gillespie, a palaeontologist at the University of New South Wales.

“It was not lion-size or even bob-cat-size. Weighing only about 600g, it was more like a ringtail possum in size,” said Anna, who was lead author on the paper describing the species, published in the journal Palaeontologia Electronica.

marsupial lion silhouettes UNSW

Size differences between Microleo attenboroughi and the three other genera of marsupial lions, Priscileo, Wakaleo and Thylacoleo. (Credit: UNSW)

The fossil were recovered from a limestone deposit dubbed Neville’s Garden Site, which is believed to have formed in a pool within a rainforest landscape about 19 million years ago, during the Miocene. The researchers unearth part of the new species’ skull and teeth.

“Despite its relatively small size compared with the Pleistocene Thylacoleo carnifex – the last surviving megafaunal marsupial lion – the new species was one of the larger flesh-eaters existing in its ancient community of rainforest creatures at Riversleigh,” explained Mike Archer from UNSW, co-author on the paper.

According to Anna, M. attenboroughi probably “scampered among the tree-tops, gobbling insects as well as small vertebrates such as lizards and birds while simultaneously trying to avoid becoming a prey item for its larger relatives.”

This new specimen of the small flesh-eater is the only of its kind to be unearthed in 40 years of research at Riversleigh, leaving many more questions about the species’ lifestyle.

“Tantalising questions about the rest of its skull and skeleton which could further clarify aspects of its lifestyle – such as whether it had an enlarged ‘killing’ thumb claw like its Pleistocene relative – must await discovery of more complete specimens,” said Mike.