image: ©
Pollyanna von Knorring (Swedish Museum of Natural History)
Researchers have rediscovered 250 million-year-old fossils revealing that ancient, crocodile-like “sea-salamanders” inhabited Australia’s coasts. These predators diversified and migrated globally shortly after Earth’s largest mass extinction, following prehistoric coastlines across the planet
Around 250 million years ago, the arid deserts of northwestern Australia were a lush, shallow bay teeming with marine life. A recent study published in the Journal of Vertebrate Palaeontology has revitalised interest in this era by identifying a diverse community of ancient marine amphibians.
These findings, based on fossils rediscovered in museum collections after 50 years, provide new insights into how land-living animals adapted to the sea following the Earth’s most devastating mass extinction.
The mystery of the lost trematosaurs
The fossils were originally unearthed in the Kimberley region during the 1960s and 70s but were later lost or forgotten in international archives. Their rediscovery in 2024 allowed researchers from the Swedish Museum of Natural History to perform a modern reassessment. These creatures were trematosaurids—crocodile-like relatives of modern salamanders that reached lengths of up to two meters.
Geologically, trematosaurids are among the oldest known marine tetrapods of the Mesozoic era. They appeared less than a million years after the end-Permian mass extinction, a period of extreme global warming that forced a rapid evolution of new marine apex predators.
A diverse coastal community
Initial research from 1972 suggested the fossils belonged to a single species, Erythrobatrachus noonkanbahensis. However, high-resolution 3D imaging has revealed a more complex ecosystem. The remains actually represent at least two distinct types of predators that shared the same habitat but hunted differently:
Erythrobatrachus:
A large-bodied predator with a broad, 40 cm skull, likely sitting at the top of the local food chain.
Aphaneramma:
A contemporary with a long, thin snout designed specifically for catching small, agile fish.
Global travellers of the ancient seas
One of the most surprising takeaways from the study is the “globe-trotting” nature of these amphibians. While Erythrobatrachus has only been found in Australia, Aphaneramma fossils have been discovered as far away as the Russian Far East, Pakistan, Madagascar, and even the Scandinavian Arctic.
This suggests that these early marine pioneers dispersed across the planet with incredible speed, likely following the coastlines of the interconnected supercontinents. The presence of these identical genera in both hemispheres proves that the transition from land to sea was a synchronised, global event that shaped the dawn of the Age of Dinosaurs.
