Researchers from the University of South Wales, Australia discovered the remains of a new small species of extinct marsupial lion that date back 18 million years ago at the Riversleigh World Heritage Area in northwestern Queensland. Due to its small size, the team named it Microleo attenboroughi, in honor of Sir David Attenborough, a broadcaster and naturalist who supported the Riversleigh World Heritage Area.

Compared to other long-gone marsupial lion families, the latest discovered species is smaller, which weighed as little as 600 grams. Anna Gillespiec, the study’s lead author from the university, even describes Microleo attenboroughi as cute, although she says that they are feisty animals.

The findings, including the animal’s sharp teeth and some part of the skull, are now available in the journal Palaeontologia Electronica. The tiny marsupial lived alongside and competed for food with two bigger species of marsupial lion, which grew as big as a cat and dog, respectively. Microleo most likely ate insects, lizards and birds while trying its best to avoid become prey for bigger relatives.

David Attenborough

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

“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 the ancient community of rainforest creatures at Riversleigh,” says study researcher Mike Archer, a professor from UNSW.

The fossil remains still need further analysis. The research team adds that they need to study the skull and skeleton to determine the marsupial lion’s lifestyle. They also claim that they need a more complete set of remains of Microleo attenboroughi to solve some of its mysteries.

The Riversleigh site is known for its diverse fossil finds. During the early Miocene period, this northern Australian site had a very wet climate, which allowed diverse mammals to flourish. Its diversity is even more impressive than other Australian locations and is usually compared to Borneo.

In the last 40 years, researchers have excavated thousands of bones and teeth in the area. Interestingly, only one species of tiny carnivore has been discovered so far despite the countless bones found.