Enigmatic lizards somehow survived near Chicxulub asteroid impact
The night lizards may have been the only terrestrial vertebrates that survived in the region of the asteroid impact 66 million years ago, which led to the extinction of non-avian dinosaurs
By James Woodford
25 June 2025
A yellow-spotted tropical night lizard
Dante Fenolio/SCIENCE PHOTO LIBRARY
A small, secretive group of lizards that still exists today may have been the only terrestrial vertebrates that survived in the vicinity of the Chicxulub asteroid collision, which led to the extinction of the non-avian dinosaurs.
It has long been known that xantusiid night lizards are an ancient lineage that have persisted for tens of millions of years. But Chase Brownstein at Yale University and his colleagues suspected that the group may have actually arisen earlier than previously thought: in the Cretaceous Period, which ended around 66 million years ago.
Read more
There’s growing evidence the big five mass extinctions never happened
Advertisement
The end of the Cretaceous was marked by a giant asteroid strike in the vicinity of Yucatán peninsula in Mexico, which left a crater over 150 kilometres wide and caused the extinction of most of the animal and plant species across the world.
Today, the night lizards – a misnomer, as they aren’t actually nocturnal – are still found in Cuba, Central America and the south-west of the US.
Brownstein and his team used previously published DNA sequence data for xantusiids to create an evolutionary tree for the group. They combined this with skeletal anatomy across living and fossil night lizards, allowing the team to determine how old their lineages are and estimate how many offspring the ancestral night lizards would have produced.
