How the death of dinosaurs led to the rise of snakes

The doom of dinosaurs were good news for snakes. According to a new study, snake biodiversity began to increase shortly after the mass extinction of the Cretaceous – Paleogene – you know, caused by a huge asteroid impact 66 million years ago. The asteroid has caused the extinction of about 75 percent of all species and all non-bird dinosaurs.

But the blow allowed the original snake species and space to thrive, and they did. There are currently about 4,000 species of elongated, legless reptiles. To study this evolutionary change, a team of researchers is studying the diet of existing snake species to look back. “After the disappearance of K – Pg, [snakes] has just suffered this huge environmental explosion, “Michael Grundler, one of the authors of the article and a UCLA researcher, told Ars.

It turns out that snake fossils are hard to find. Large snakes are rare because their bodies are poorly dismembered and can fragment quickly. “They are really rare in fossil records. And when we see them in fossils, they’re usually just a few vertebrae, they’re often not really skulls, so we can’t get an idea of ​​their ecology, “Grundler said. “It’s not like a big mammal or a big dinosaur that has four limbs and the bones are pretty strong. With snakes you have all these fragile vertebrae … their skulls are also quite poorly dissected. “

Therefore, the team behind the new study resorted to comparisons between existing species. The researchers reviewed the nutritional information of 882 species of snakes, often stored in museum collections, and applied a mathematical model to reconstruct the diet of their ancestors. It may seem difficult to learn anything about the ancestors of snakes millions of years ago, but Grundler said that as long as we have good data on living species and their evolutionary relationships, it is possible to trace their lineage.

According to the researchers’ model, the most likely common ancestor of all existing snake species is the insectivorous. Before the mass extinction, there were probably snakes that ate rodents and other animals. However, after the asteroid’s impact, these beasts may have died, although this is still uncertain, Grundler said. “What we get from the model is the best guess,” he said.

(Somewhere further back, it is also a common ancestor between snakes and other reptiles, but how it looks and behaves is still debated, he said.)

After extinction, other snakes thrive and diversify into many different species. This is probably because many niches were left open after the impact. Similarly, there were more small vertebrates, like birds, to prey on. But with the diversification of snakes came the growing variety in terms of diet – sometimes they eat crazy big things like antelopes. “Modern snakes have a huge, amazing variety of diets,” Grundler said. “They all developed this diversity from a single ancestor.”

The study also shows that the increase in snake biodiversity is slowing down for most snake species as they settle in their new habitats. However, the species that reached new localities continued to adapt in different ways.

According to Grundler, this study can help us understand how genera respond to environmental opportunities. It also complements research on the ecological history of snakes; another document published in September shows similar findings. “It also speaks to the importance of our natural history museums and the collection of data on animals in the wild,” he said.

This story originally appeared on Ars Technica.

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