Daily BulletinDaily Bulletin

The Conversation

  • Written by Anna Gillespie, Technical Researcher, UNSW

My colleagues and I have discovered a new species of marsupial lion, Wakaleo schouteni, from the Riversleigh World Heritage Area in northwest Queensland. The species was the size of a Collie dog and weighed about 23 kilograms.

Fossils of this species include a beautifully preserved skull, jaws and upper arm bones. These were recovered from sites that have been dated at around 18 million years old (a period known as the early Miocene), and from others that are estimated to be older (the late Oligocene period, approximately 23 million years old).

Read more: Giant marsupials once migrated across an Australian Ice Age landscape

Not really a lion

“Marsupial lions”, also known as thylacoleonids, are an extinct family of marsupials that were present in Australia from about 24 million years ago up until the end of the Pleistocene era, about 30,000 years ago.

image The site in Queensland where the Wakaleo schouteni fossil skull was found. Anna Gillespie, Author provided

Their distinguishing feature is the presence of lengthened premolar teeth that form a pair of secateur-like blades. This feature – massively developed in the most recent member of the family, Thylacoleo carnifex – led to them being named a “marsupial lion” by the 19th century palaeontologist Sir Richard Owen.

At present, the thylacoleonid family contains nine species, five of which belong to the genus Wakaleo.

image Species of marsupial lions varied hugely in size. Anna Gillespie, Author provided

Previously, species of Wakaleo were known from younger sites that spanned the middle Miocene to the late Miocene era, dating to approximately 17 to 5 million years ago. These species were roughly dog-sized and appeared to have formed a morphocline – that is, a series of animals with certain features that gradually evolved over time, with each species being sequentially replaced. The Wakaleo species increased in size over millions of years.

These species were distinguished from other marsupial lion species by loss of the front premolar tooth or teeth. However, the newly found Wakaleo schouteni species retains these premolars, indicating that the earlier members of the genus had features that were more primitive.

This feature was shared with another marsupial lion from around the same period: Priscileo pitikantensis from central Australia. It was possible that this relatively poorly-preserved species may have been actually a species of Wakaleo.

Our new study undertook a review of that specimen and found similarities of its molars and humerus (the upper-most bone of the upper limb) with those of W. schouteni, confirming that it was a species of Wakaleo (now Wakaleo pitikantensis).

A look at the bones

The skull of Wakaleo schouteni is around 16.5cm long. Shown below, at the left end is the nose, and most of the face. In the middle is the cheek bone (which is incomplete) and the socket for the eye, and at the right end is the brain case.

image A photograph of the Wakaleo schouteni skull, shown from the left side. Anna Gillespie, Author provided

The new species of Wakaleo from Riversleigh differs from the central Australian Wakaleo in being slightly larger and differing in the morphology of the shoulder-end of the humerus bone. In anatomy, “morphology” is a term that describes the appearance and the structure of a part of the body.

These differences in the humerus suggest that the two species moved their arms slightly differently - we’re looking at this closely now as part of our ongoing research.

What Australia used to be like

The fossils that we find in a region can tell us a lot about what habitats were like in the past.

On the basis of the diversity of the mammals recovered from Riversleigh, the region in the late Oligocene and early Miocene Australia is believed to have been forested. We think the earlier period (approximately 23 million years old) had relatively open forests, and the later period (around 18 million years old), more closed forests, possibly rainforests.

It is highly likely that Wakaleo schouteni pursued its prey – small vertebrates like lizards, frogs, birds and small mammals – through the tree-tops of these forests.

Read more: Riversleigh is a remarkable natural history museum

Given the apparent changes over time we’ve seen within the Wakaleo species of marsupial lion, it is possible that the slightly smaller species from central Australia may be slightly older than the larger Wakaleo schouteni.

Alternatively, these animals may represent what is known as allopatric species: this means they evolved separately due to geographic isolation.

Whatever the scenario, this new findings push the origins of the Wakaleo genus back into the late Oligocene period, around 23 millions years into Australia’s past, and point to even earlier origins for marsupial lions than we had previously thought.

Authors: Anna Gillespie, Technical Researcher, UNSW

Read more http://theconversation.com/a-new-species-of-marsupial-lion-tells-us-about-australias-past-88633

It's one thing to build war fighting capability, it's another to build industrial capability


Melbourne tower lockdowns unfairly target already vulnerable public housing residents


Explainer: will life mean life when the Christchurch mosque killer is sentenced?


The Conversation


Prime Minister Interview with Ben Fordham, 2GB

FORDHAM: Thank you very much for talking to us. I know it's a difficult day for all of those Qantas workers. Look, they want to know in the short term, are you going to extend JobKeeper?   PRI...

Scott Morrison - avatar Scott Morrison

Prime Minister Scott Morrison interview with Neil Mitchell

NEIL MITCHELL: Prime minister, good morning.    PRIME MINISTER: Good morning, how are you?   MICHELL: I’m okay, a bit to get to I apologise, we haven't spoken for a while and I want to get t...

Scott Morrison - avatar Scott Morrison

Prime Minister Interview with Ben Fordham

PRIME MINISTER: I've always found that this issue on funerals has been the hardest decision that was taken and the most heartbreaking and of all the letters and, you know, there's been over 100...

Scott Morrison - avatar Scott Morrison

Business News

SEO In A Time of COVID-19: A Life-Saver

The coronavirus pandemic has brought about a lot of uncertainty for everyone across the world. It has had one of the most devastating impacts on the day-to-day lives of many including business o...

a Guest Writer - avatar a Guest Writer

5 Ways Risk Management Software Can Help Your Business

No business is averse to risks. Nobody can predict the future or even plan what direction a business is going to take with 100% accuracy. For this reason, to avoid issues or minimise risks, some for...

News Company - avatar News Company

5 Ways To Deal With Unemployment and Get Back Into the Workforce

Being unemployed has a number of challenges and they’re not all financial. It can affect you psychologically and sometimes it can be difficult to dig your way out of a rut when you don’t have a job ...

News Company - avatar News Company

News Company Media Core

Content & Technology Connecting Global Audiences

More Information - Less Opinion