WA crocodile-like ‘sea-salamander’ fossil produces new discovery 50 years after being lost in museum bungle

The remains of an ancient marine amphibian that once stalked the WA coastline was first lost to time and then lost to a museum bungle.

Go back 252 million years to the Mesozoic era, the dawn of the age of dinosaurs, and what is now the searing desert of WA’s Kimberley region was the shore of a shallow bay at the edge of a vast prehistoric ocean.

Modern marine ecosystems were just starting to emerge following the cataclysmic mass extinction at the end of the Permian period, giving rise to the earliest sea-going limbed vertebrates, tetrapods, which established themselves as the dominant predators of the seas.

The majority of fossils of these creatures have been found in the northern hemisphere, so it was significant when a paper was published in 1972 describing several tetrapod skull fragments weathering out of a rocky outcrop on Noonkanbah cattle station east of Derby.

The researchers back then dubbed the new species Erythrobatrachus noonkanbahensis, before distributing the specimens between museum collections in Australia and the US.

The specimens were lost at some point in the ensuing years, prompting an international search effort that culminated with the 2024 discovery that one of the Noonkanbah fragments had been mislabelled and had been gathering dust in the vault at Berkeley in California.

Now a team of researchers from the University of New England, WA Museum Boola Bardip, Curtin University and the University of New South Wales has made a second remarkable discovery.

Erythrobatrachus was a trematosaurid temnospondyl, which might superficially be described as a crocodile-like relative of modern salamanders and frogs that grew up to 2m in length.

But when the team examined the lost fossil fragment from Berkeley and compared it to a high-quality plaster cast of another of the fragments, they found something unexpected.

High-resolution 3D imaging of both specimens revealed not one species of trematosaurid but two — Erythrobatrachus and another species attributable to the well-known genus Aphaneramma.

The findings were published in the Journal of Vertebrate Paleontology.

While Erythrobatrachus has exclusively been found in Australia, fossils of Aphaneramma have been reported from the Scandinavian Arctic, the Russian Far East, Pakistan and Madagascar.

So the new findings on the Noonkanbah fragments reveal these earliest Mesozoic marine tetrapods were much more prevalent in prehistoric oceans than previously thought.

The rediscovered fossils of Erythrobatrachus are being repatriated to Australia.