The mystical night lizard survived a massive asteroid attack that ended the dinosaur reign 66 million years ago, despite living right next to the impact site, new research finds.
Thanks to new evolutionary analysis, researchers have discovered that small lizards from the family Xantusiidae live around the Gulf of Mexico before and after it hit the Yucatan Peninsula in Mexico. This makes the Night Lizard the only group of vertebrates on the land known to survive near the impact location, and has members who still live in the area today.
The dinosaur’s end asteroid was about 7.5 miles (12 kilometers) wide, causing widespread devastation when it collided at the end of the Cretaceous period (145 to 66 million years ago). This shock has been devastating for most of the Earth’s wildlife, causing a mass extinction event of the Cretaceous-foliate gene (K-PG), in which approximately 75% of all species have died. However, two strains of the Night Lizard could last throughout the disaster, despite being close enough to see the impact.
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“They would have been around the edge of the impact on the asteroid,” Chase Brownstein, a doctoral candidate for the Department of Ecology and Evolutionary Biology at Yale University, told Live Science.
Of all the devastation, how did the night lizard survive? Researchers aren’t sure, but Brownstein noted that they had slow metabolism, so they wouldn’t have had to eat too often.
The researchers presented in a biology letter on Wednesday (June 25th).
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Night lizards grow to a few inches long. Very secret lizards often live in rock gaps, dense vegetation, or specialized microhabitats such as bark and logs.
Several previous studies suggested that the “crown” group of night lizards (a group containing the last common ancestor of all living night lizards evolved into the age of dinosaurs. New research tested that hypothesis.
Brownstein and his colleagues reconstructed the ancestors of three living Knight Lizard genus (lepidophyma, Xantusia, and cricosaura). They used molecular clock dating to estimate when night lizards evolved, based on their mutations and the rate at which mutations occur in DNA over time.
Researchers discovered that a recent common ancestor appeared in the Cretaceous period 90 million years ago, and that lizards of the night had lived in North and Central America from that time.
New findings suggest that the two-night lizard lineage survived the asteroid attack. One of these strains caused Xantusia, which ranged from the southwest of the US to Mexico, and Xantusia, which ranged from the scale pidophyma, which ranged from North and parts of Central America. The second lineage produced Clicosaura and its only species, Cubanite lizard (Clicosauratica), in Cuba.
The Night Lizards were not the only animals to survive the K-PG mass extinction event. We would not be here today if some of the mammalian family trees hadn’t experienced the asteroid impact. Bird dinosaurs (birds), fish, and many other animals also survived. However, nocturnal lizards are the only surviving group of terrestrial vertebrates that have remained endemic to North and Central America since the asteroid struck.
Brownstein said several strains of turtles and other lizard strains in the area probably survived the asteroid in a similar way to night lizards (the scientifically named Xantusiids). However, these other strains have disappeared ever since.
“The problem is, they’re not there anymore,” Brownstein said. “So what’s interesting is that Xantusiid is stuck and remains indigenous to the region.”
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