60 million years of climate change drove reptile evolution and diversity

60 million years of climate change drove reptile evolution and diversity

Artistic reconstruction of reptilian adaptive radiation in terrestrial ecosystems during the warmest period in Earth’s history. The images depict large, large-headed, carnivorous red crocodiles (close relatives of crocodiles and dinosaurs) and small gliding reptiles from around 240 million years ago. The red-nosed dragon was chasing the gliding reptile, propelling itself through the hot, dry river valley using the fossilized bones of the extinct Dimetrodon, an early mammal ancestor.Credit: Henry Sharp

Just over 250 million years ago, at the end of the Permian and the beginning of the Triassic, reptiles had a big party.


Their rate of evolution and diversity began to explode, leading to a dizzying array of abilities, body plans, and traits, and helping to firmly establish their extinct lineage and what remains today as the world’s most successful and diverse The pedigree of one of the animal groups has ever been seen. For the longest time, the reason for this boom was that their competition was wiped out by the two largest mass extinction events in Earth’s history (roughly 261 and 252 million years ago).

A new Harvard-led study rewrites this explanation by reconstructing how the bodies of ancient reptiles changed and comparing it to millions of years of climate change.

The lab of Harvard paleontologist Stephanie Pierce shows that the morphological evolution and diversification of early reptiles not only began a few years before these mass extinction events, but was directly driven by what caused them in the first place—climate Directly driven by rising global temperatures due to change.

“We think we have two major factors at work – not just this open ecological opportunity that a few scientists have been thinking – and something that no one has figured out before, which is that climate change is actually directly triggering the Tiago R. Simões, a postdoctoral researcher in the Adaptive Response Pierce lab and lead author of the study, said:

“basically, [rising global temperatures] Triggered all these different morphological experiments – some worked so well that they survived for millions of years today, while others largely disappeared after a few million years,” adds Simões.

Posted on Friday in scientific progressthe researchers list the dramatic anatomical changes that occurred in many reptile groups, including the precursors of crocodiles and dinosaurs, in direct response to major climate changes centered between 260 and 230 million years ago.

The study takes a closer look at how a large group of organisms have evolved due to climate change, which is especially important today as temperatures continue to rise. In fact, the rate of carbon dioxide being released into the atmosphere today is about nine times faster than during the largest mass extinction driven by climate change: the Permian-Triassic mass extinction 252 million years ago.

“Significant changes in global temperature could have large and varied impacts on biodiversity,” said the Stephanie E. Pierce, Thomas D. Cabot Associate Professor of Organic and Evolutionary Biology and Curator of Vertebrate Paleontology at the Museum of Comparative Zoology. “Here, we show that warmer temperatures during the Permian-Triassic led to the extinction of many animals, including the ancestors of many mammals, but also triggered the explosive evolution of other animals, especially during the Triassic period that dominated reptiles.”

The study involved nearly eight years of data collection and extensive photography, CT scans and numerous passport stamps as Simões traveled to over 20 countries and over 50 different museums to take scans and snapshots of over 1,000 reptiles fossil.

Using all the information, the researchers created an extensive dataset, which was analyzed using state-of-the-art statistical methods to generate a graph called an evolutionary time tree. Time trees reveal relationships among early reptiles, when their lineages first originated, and how quickly they evolved. They then combined this with global temperature data from millions of years ago.

The diversification of reptile body plans began about 30 million years before the Permian-Triassic extinction, suggesting that these changes were not triggered by events as previously thought. The extinction event did help them prepare, though.

The dataset also showed that global temperature increases began around 270 million years ago and continued until at least 240 million years ago, followed by rapid changes in the bodies of most reptiles. For example, some larger cold-blooded animals evolved to become smaller in order to cool more easily; others evolved to be aquatic life for the same effect. The latter group includes some of the strangest forms of reptiles that will continue to go extinct, such as the giant long-necked marine reptile once thought to be the Loch Ness monster, a small chameleon creature with a bird’s skull and beak, and a species like the Loch Ness monster. A gliding reptile with wings like a gecko. It also includes the ancestors of reptiles that still exist today, such as turtles and crocodiles.

The small reptiles that gave rise to the first lizards and tuatara took different paths from their larger reptilian brethren. Their evolution slows down and stabilizes as temperatures rise. The researchers believe this is because smaller reptiles have adapted better to rising heat, as they release heat from their bodies more easily than larger reptiles when temperatures around the planet heat up quickly. .

The researchers say they plan to expand the work to investigate the impact of environmental disasters on the evolution of organisms with rich modern diversity, such as major groups of lizards and snakes.


Did adaptive radiation shape reptile evolution?


More information:
Tiago R. Simões, Past successive climate crises drove early evolution and radiation of reptiles, scientific progress (2022). DOI: 10.1126/sciadv.abq1898. www.science.org/doi/10.1126/sciadv.abq1898

Provided by Harvard University

Citation: 60 Million Years of Climate Change Driving Reptile Evolution and Diversity (19 Aug 2022) Retrieved 20 Aug 2022 from https://phys.org/news/2022-08-million-years- climate-drove-evolution.html

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