Asteroid Strike that Killed Dinosaurs Wiped Out Snakes and Lizards

The massive asteroid collision that is thought to have killed dinosaurs 65 million years ago also destroyed the majority of snake and lizard species, reveals a new study.

Earlier studies have suggested that an asteroid crashed into the Yucatan peninsula in Mexico, wiping out the dinosaurs and other giant reptiles like plesiosaurs. The impact of the asteroid collision released a cloud of dust that blocked the sunlight and prevented plants from producing food. This caused the dinosaurs to become extinct, reports LiveScience.

It was presumed that only some species of snakes and lizards became extinct after the asteroid struck Earth. But researchers from Yale and Harvard universities have found that at least 83 percent of the snake and lizard species died in the asteroid event.

"The asteroid event is typically thought of as affecting the dinosaurs primarily," lead author of the study Nicholas R. Longrich, from Yale University, said in a statement. "But it basically cut this broad swath across the entire ecosystem, taking out everything. Snakes and lizards were hit extremely hard."

For their study, the research team examined fossils of snake and lizard species collected across North America. They analyzed 21 previously known species and nine new species of lizards and snakes that existed before the mass extinction.

It also included a tall lizard species that was identified based on fossils recovered from Montana's Hell Creek Formation. The lizard has been named Obamadon gracilis, a Latin term where odon means "tooth" and gracilis means "slender". The lizard belonged to the group of creatures called Polyglyphanodontia.

When researchers examined fossil records after the dinosaur extinction, they found that only five species of the reptiles remained, with no fossil records on other species. This indicates that most of the reptiles, including members of Polyglyphanodontia, were wiped out at the end of the Cretaceous period, following an asteroid collision.

Researchers suggested that the big creatures more likely became extinct, with species weighing more than one pound not being able to survive the strike.

The extinction of big creatures paved the way for the evolution and diversification of survivors by removing the competitors, said researchers. Around 9,000 species of snakes and lizards are living today.

"They didn't win because they were better adapted, they basically won by default, because all their competitors were eliminated," Longrich said.

The findings of the study, "Mass Extinction of Lizards and Snakes at the Cretaceous-Paleogene Boundary", appear in the online publication of the journal Proceedings of the National Academy of Sciences.