The asteroid collision that killed off the dinosaurs 65.5 million years ago also nearly wiped out snakes and lizards - including a newly-identified species of lizard named for President Obama.
As many as 83 percent of all snake and lizard species died off, says the Yale team, far more than previously realized. The bigger the creature, the more likely it was to become extinct - indeed, no species larger than one pound survived.
"The asteroid event is typically thought of as affecting the dinosaurs primarily," says Nicholas R Longrich, a postdoctoral associate with Yale's Department of Geology and Geophysics.
"But it basically cut this broad swath across the entire ecosystem, taking out everything. Snakes and lizards were hit extremely hard."
The results are based on a detailed examination of previously-collected snake and lizard fossils discovered across western North America. Thesae included 21 previously-known species, as well as nine new lizards and snakes.
"Lizards and snakes rivaled the dinosaurs in terms of diversity, making it just as much an 'Age of Lizards' as an 'Age of Dinosaurs,'" says Longrich.
But many survived, leading to the 9,000-odd species of lizards and snakes we see today.
"They didn't win because they were better adapted, they basically won by default, because all their competitors were eliminated," says Longrich.
One of the most diverse lizard branches wiped out was the Polyglyphanodontia, which included up to 40 percent of all lizards then living in North America.
And while reassessing previously collected fossils, the team came across an unnamed species which they called Obamadon gracilis - meaning something like 'slender Obama-tooth'. It likely measured less than one foot long and probably ate insects.
Longrich says he's not making a political point with the name: "We're just having fun with taxonomy," he says.