Why there are so many species of serpent

California News Times

NSHE CenozoicThe era of Earth’s history since the collision of asteroids 66 meters ago ended the reign of dinosaurs is often referred to as the era of mammals. And mammals did succeed in scrambling to fill the ecological niche suddenly emptied by the catastrophe. There are currently about 6,500 species of mammals. However, several other groups were successful as well. Birds (technically, dinosaurs are rarely thought of by their ancestors) are home to about 11,000 species. There are 7,000 lizards.

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And there is yet another set of terrestrial vertebrates that thrived after the collision, but sadly ignored by zoologists. These are snakes. With nearly 4,000 representatives, it is not as unique as mammals. But they are not too late.

The success of snakes is intriguing. Phylogenetically, they are actually a group of lizards that have lost their legs, much like birds are wing-germinated dinosaurs. But the success of birds is not surprising. They were the only dinosaurs to master the flight. In contrast, partial or total lameness has evolved more than dozens of times in lizards. Still, with the exception of snakes, every time they abandoned their limbs, there were only a handful of modern representatives.

In a study just published in PLOS biologyMichael Grundler of the University of California, Los Angeles and Daniel Rabosky of the University of Michigan shed light on this issue. They say that the unique success of snakes among legless lizards is the result of a significant diversification of their diet made possible by a new group of animals that thrived after the death of (non-avian) dinosaurs. Insist. To support their theory, they have compiled information on the diet of 882 modern snake species. We then mapped this to the best available understanding of the snake family tree.

The oldest snake fossil dates back to the Middle Jurassic, about 170 meters ago. These snakes were predators of invertebrates, mainly insects. Therefore, their diet was consistent with that of most other groups of limbless lizards currently alive. But more than 100 million years ago, as the graph shows, Dr. Grundler and Dr. Rabosky’s analysis suggests that some snakes have begun to eat other lizards. This dietary change was probably made possible by the evolution of what was considered a snake killer app at the time. This corresponds to a bird’s feather, if necessary. This disengages the lower jaw from the upper jaw, giving it the famous ability to swallow whole prey. Then, about 75 meters ago, some snakes began adding other small vertebrates, such as frogs, to their diet.

But it was just an overture. As the graph shows, the diversification of the Ophidian’s diet actually progressed during the so-called Eocene, which began 10 million years after the death of the dinosaurs and 56 million years ago. Many groups of animals now familiar first appeared during the Eocene (including the most modern orders of mammals). Snakes that prey on this diversity have diversified accordingly and developed the infamous poison-like hunting tricks. As a result, there are a large number of chunky snakes found today. ■■

This article was published in the printed version of the Science and Technology section under the heading “Snakes alive!”.


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