Evolution: explosion of snakes (Evolution)

by David Turell , Friday, February 23, 2024, 16:16 (272 days ago) @ David Turell

A dramatic evolution of thousands of species of snakes since dinosaurs went extinct:

https://www.livescience.com/animals/snakes/snakes-are-built-to-evolve-at-incredible-spe...

"Snakes have a supercharged evolutionary clock that enables them to adapt at far faster rates than other reptiles, scientists have discovered. This ability has helped them become evolutionary "winners" and spread across the planet.

"'Snakes are like the Big Bang 'singularity' in cosmology — a dramatic expansion of diversity in species and their ecologies, linked to some event that might have occurred early in the evolutionary history of snakes," lead author Pascal Title,

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"The scientists looked at squamates, the order of reptiles that includes snakes and lizards and includes over 11,000 species. In this group, snakes, in particular, are widely diverse — the roughly 4,000 known snake species vary from venomous sea snakes, giant constrictors and hooded cobras to tiny threadsnakes that burrow to feed on ants and termites.

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"Their findings suggest that snakes underwent several evolutionary explosions and evolved three times faster than lizards, in terms of diversity. After likely first emerging about 128 million years ago, there was a huge burst at some point between then and 70 million years ago, during the Cretaceous period (145 million to 66 million years ago), and another major pulse after the dinosaurs went extinct at the end of the Cretaceous.

"'Compared to lizards, they have changed relatively rapidly, and they've continued to do so through time," Rabosky said. "So we would also say that the continued 'evolutionary explosion' of snakes is still ongoing today and appears partly driven by the fact that the rate of evolution — their 'evolutionary clock' so to speak — is just ticking a lot faster than many other groups of animals. This fast-ticking-evolutionary-clock is really important because it lets snakes evolve new traits quickly that can take advantage of opportunities that come up."

"Snakes' evolutionary flexibility enables them to change their body shape and diets "very quickly," he said. The initial "singularity" that led to snakes' success appears to have started with them developing limbless bodies, flexible skulls and advanced chemical-detection systems.

"These changes enabled them to target a huge array of prey, providing the framework for individual species to develop and specialize. Previous research published in 2021 shows the diversity in their diets exploded after the dinosaurs went extinct, with snakes quickly evolving new adaptations to take advantage of the new world they found themselves in — a dinosaur-less world in which mammals were starting to gain a foothold.

"But why snakes ended up with a fast evolutionary clock in the first place is still a mystery. "This is the big question for us," Rabosky said. "We can’t really explain this yet."

Comment: every species evolving since dinosaurs have created ecosystems into which there is a place for snakes. They are certainly a unique form of vertebrate, going from legged to legless as if it shows evolution going backwards. Loss of locomotion resulted in an amazing set of changes to make up for it. Not by natural selection, but by design.