Ancient amphibian fossils unearthed in Brazil
Museum scientist Dr Martha Richter helps discover two new species of extinct amphibians and the oldest reptile fossil skeleton ever found in South America.
The two species of aquatic amphibians lived around 280 million years ago in what is now Brazil. They belong to an extinct group known as dvinosaurs, which are distant relatives of modern salamanders.
The international team of researchers, who published their findings in the journal Nature Communications, say the discoveries will help to shed light on the evolution and adaptation of amphibians, including in response to rapid environmental change.
They also found the oldest South American bone remains of a reptile. Skeletal remains of the lizard-like Captorhinus aguti have previously only been found in rocks of the same age in North America, and much younger rocks in southern Brazil.
One of the new species, Timonya annae, was a small, fanged creature that grew up to 40 centimetres long. It resembled a cross between an axolotl and an eel and had a long, flexible body optimised for eel-style swimming.
T. annae had a large head and a strong pectoral (chest) skeleton, while its limbs were small and strong-boned.
The researchers think Procuhy nazariensis had very similar features and grew to a similar length to T. annae, but no complete skeleton was found.
The scientists also unearthed the skull remains of another kind of amphibian, a rhinesuchid stereospondyl. Relatives of this amphibian lived in parts of Africa, India and southern Brazil around 20 million years later.
Until now, we’ve known very little about what four-legged vertebrates lived in the southern tropics during this period early in their evolutionary history.
The discoveries will help scientists map the way animals spread during the Permian period, 299 to 251 million years ago, and settled in new areas.
Dr Richter, palaeontologist at the Museum and co-author of the study, explains the importance of the new finds in South America:
'This discovery is remarkable as most of what we understand about the evolution and adaptation of amphibians through time is based on animals located in Europe and North America.
'Now that we know that their distant relatives inhabited a vast lake system in the tropical region of the supercontinent Pangaea in areas that correspond to northeastern Brazil, we can find out more about their abundance, palaeobiology and how wide their distribution away from the Equator was.'
Learning from the past
The findings will contribute to understanding how climate change threatens present-day amphibian populations and their habitats.
The end of the Permian period saw the worst mass extinction known to date. Conditions became so inhospitable that more than 90 per cent of the world’s species went extinct. Today, wildlife is again facing rapid and dramatic climate change.
Dr Richter elaborates, 'We and the rest of the modern faunas are in danger of having to face dramatic climate change within only a few decades.'
Although the configuration of the continents and climate were different in the Permian period, investigating how ecosystems altered in response to past environmental changes can reveal details that help us model future impacts.
'Understanding the composition of extinct faunas like this in Brazil and how they changed through time may help us to better predict how today’s lake systems and their complex communities of animals will evolve in response to the extensive global environmental changes,' says Dr Richter.