Lizard fossil discovered in Italy rewrites reptile history
A new study of a 240-million-year-old lizard fossil has shed new light on early lizards and rewritten part of reptile history.
The fossilized lizard-like creature, nicknamed Megachirella wachtlerihas been determined to be the oldest known squamate – a group of reptiles including snakes, lizards and legless lizards – and suggests that these animals appeared earlier than previously thought.
The specimen was found by an amateur fossil hunter in the Dolomites, part of the Italian Alps, in the early 2000s, but scientists have not been able to determine exactly where the ancient reptile stood in evolutionary history. Although scientists believed the creature was related to modern squamates, there wasn’t enough evidence to classify it as a direct ancestor, reports National geographic.
In a new analysis, published Wednesday in the journal Nature, an international team of paleontologists reanalyzed the fossil using data from high-resolution CT scans. CT scans provided 3D images of the fossil, allowing scientists to see previously hidden details of the animal encased in rock. Scans revealed several characteristics unique to lizards, including parts of the creature’s collarbone, skull, and wrists, reports The Washington Post.
Over the course of 400 days, researchers examined 150 fossil specimens of lizard-like animals held in collections around the world. The team also collected molecular data, including DNA, and skeletal data from modern squamates and concluded that Megachirelle was an ancient squamate, making it the oldest ever discovered.
“All lizards and snakes are descendants of Megachirelle or one Megachirelle-like a lizard,” said study co-author Dr Massimo Bernardi, from the University of Bristol. The Guardian. Bernardi added that Megachirelle probably would have been about 25-30 centimeters long.
“The specimen is 75 million years older than what we thought to be the oldest fossil lizards anywhere in the world and provides valuable information for understanding the evolution of living and extinct squamates,” said lead author Tiago Simões. , from the University of Alberta. a Press release accompanying the study.
The new data – which the team says is the largest set of reptile data ever compiled – also allowed the researchers to estimate when the first squamates appeared on Earth. The data showed that the squamates likely appeared just before a mass extinction event 252 million years ago known as the “Great Dying”, reports The Guardian. The results contradict theories that the first squamates appeared after the mass extinction, which marked the death of 70% of terrestrial vertebrates and 90% of marine creatures.
David Martill, professor of paleobiology at the University of Portsmouth in the UK, said The Guardian that the discovery changes the perception of squamates. “That means the squamates are true survivors,” said Martill, who was not involved in the study. “The Permo-Triassic extinction event was a dangerous time to live in. Little escaped its deadly touch.