Imagine a time when Australia's rivers were teeming with life - from lungfish to flamingos, and even freshwater dolphins. It's hard to believe, but this was the case around 25 million years ago, when the outback was a tropical paradise.

Among these ancient animals was a creature that would eventually become the platypus we know today. Scientists have been studying the remains of an ancient toothed platypus, called Obdurodon insignis, and the findings are fascinating.

These ancient platypuses were quite different from the ones we see today. They had strong, well-formed teeth that they kept into adulthood - a trait that's lost in modern platypuses. In fact, the newly discovered fossils include a lower first molar, an upper second premolar, and part of the shoulder structure, which suggests that Obdurodon insignis had a powerful bite and could crush hard-shelled animals like yabbies.

The discovery of these fossils has helped scientists build a clearer picture of what Obdurodon insignis looked like. By comparing the remains with a well-preserved skull of a related species, researchers now have a better understanding of these ancient animals. And what's even more remarkable is that Obdurodon insignis was very similar to modern platypuses but slightly larger and still had teeth.

The team from Flinders University has been exploring the South Australian outback for over 20 years, searching for fossils. And their efforts have paid off, with the discovery of many species, including fish, birds, reptiles, and other mammals like freshwater dolphins. It's a testament to the rich history of life in Australia's ancient rivers.