Snappy Evolution: The Secret Behind Ancient Crocodiles' Successful Adaptation

Modern crocodiles live in rivers, streams, and forests, using their snouts and strong jaws to catch fish, snakes, birds, and mammals.

However, recent research published today in the Royal Society B journal Proceedings suggests that ancient crocodiles were once even more diverse due to accelerated evolution.

Various Ancient Crocodile Species

The team looked at over 200 skulls and jaws, including bones from crocodiles and their extinct ancestors dating back over 230 million years. They looked at shape variance to see if there were any variations between animals, and they looked at how quickly crocodile classes evolved over time.

Some extinct crocodile species, such as the dolphin-like thalattosuchians and small land-dwelling notosuchians, evolved rapidly over millions of years. Their skulls and jaws underwent major changes as they spread into niches now occupied by other animal groups, especially mammals.

Related Article: Vertebrate Origin Theory Now Questionable With Discovery of Fossilized Fish Larvae

Rapid Evolution

Crocodiles, alligators, and gharials, the only surviving crocodilians, are more cautious than these extinct fossil species and have evolved continuously over the last 80 million years, with little proof of a slowdown in their development, proving that they are not 'living fossils,' as previously believed.

"Crocodiles and their descendants are an excellent community for understanding the rise and decline of biodiversity," said lead author Dr. Tom Stubbs, a Senior Research Associate at the University of Bristol's School of Earth Sciences.

"Only 26 crocodile species exist today, with the majority of them looking very similar. Hundreds of fossil species, on the other hand, show remarkable variation, especially in their feeding apparatus."

"Modern state-of-the-art approaches now mean we can monitor for variations in the speed of evolution over time and through classes," said Dr. Armin Elsler, a Research Associate in the Bristol School of Earth Sciences and co-author.

Why Did They Evolve Rapidly?

Dramatic changes in climate and diet have long been thought to cause accelerated adaptation. Still, these patterns are normally only seen in today's diverse populations, such as birds, rodents, and fish. This is the first time this pattern has been observed in crocodiles, a species with a long fossil background but poor contemporary diversity.

"Ancient crocodiles come in a dizzying variety of shapes," said Dr. Stephanie Pierce, Associate Professor of Organismic and Evolution Biology at Harvard University. They had developed the ability to run on land, float in water, snap fish, and even chew plants.

"Our research demonstrates that these very distinct modes of life arose very quickly, allowing extinct crocodiles to survive and conquer novel ecological niches for several millions of years."

"It's not obvious why modern crocodiles are so constrained in their adaptations," said Professor Michael Benton of Bristol. If we only had living creatures, we could suggest that their modes of life are constrained by their cold-bloodedness or their anatomy.

"However, the fossil record demonstrates their incredible skills, with vast numbers of animals in the seas and on land." Maybe they thrived only when the world's temperatures were colder than they are now."

Also Read: Study Showed How The Human Brain Grew After Large Animals Went Extinct

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