In the Riversleigh World Heritage Area in north-western Queensland, scientists have discovered the fossil remains of a new species of marsupial lion that went extinct about 18 million years ago.
The lion was tiny, weighing only about 600 grams, scientists say.
The team has named the new species Microleo attenboroughi, both for its miniature size and in honor of Sir David Attenborough.
In the Riversleigh World Heritage Area in north-western Queensland, Australia, scientists have discovered the fossil remains of a new species of marsupial lion that went extinct about 18 million years ago.
The lion was tiny, weighing only about 600 grams, scientists write in a new study published in the journal Palaeontologia Electronica. In contrast, the last surviving marsupial lion that went extinct about 100,000 years ago, Thylacoleo carnifex, was lion-sized, weighed more than 100 kilograms.
The team has named the new species Microleo attenboroughi, both for its miniature size and in honor of Sir David Attenborough for “his support for the Riversleigh World Heritage Area, which he has described as one of the four most important fossil areas in the world”, the authors write in the paper.
“Microleo attenboroughi would have been more like the cute but still feisty kitten of the family,” lead author of the study, Anna Gillespie of the University of New South Wales (UNSW), said in a statement. “It’s likely that Microleo scampered amongst 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.”
The researchers recovered Microleo’s fossil remains — parts of skull and teeth — from a limestone deposit named Neville’s Garden Site. Fossils of numerous other species, such as bandicoots, possums and kangaroos, toothed platypuses, koalas, bats, fish, turtles, lizards, pythons and birds, have previously been unearthed from this deposit.
Neville’s Garden Site has also yielded fossil remains of a much larger marsupial lion, a yet-to-be described species of Wakaleo, researchers say. Similarly, other sites at Riversleigh have revealed fossils of Priscileo roskellyae, a marsupial lion that weighed around two kilograms, and was sized between M. attenboroughi and the new species of Wakaleo, that is estimated to have weighed around 30 kilograms.
So the early Miocene rainforests of Riversleigh were home to at least three marsupial lion species, the researchers conclude.
“This level of diversity is unmatched for the family at any other time in their evolutionary history,” they write in the paper.
Co-author Suzanne Hand of UNSW added: “The early Miocene of northern Australia, as documented by the thousands of fossils from Riversleigh, was a time of mild, very wet climatic conditions with mammal diversity more like that seen in Borneo than anywhere in Australia today.”
- Gillespie, Anna K., Archer, Michael, and Hand, Suzanne J. 2016. A tiny new marsupial lion (Marsupialia, Thylacoleonidae) from the early Miocene of Australia. Palaeontologia Electronica 19.2.29A: 1-25 palaeo-electronica.org/content/2016/1490-new-marsupial-lion