How night lizards survived the asteroid that ended the dinosaurs

The environmentalists of the University of Yale reveal a line of lizards who traveled the asteroid event killing dinosaurs with unexpected evolutionary survival traits. The night lizards (Xantuiidae family) survived the mass extinction event of the Cretaceous-Paleogenic (K-PG) 66 million years ago (formerly known as KT extinction) despite small broods and occupying limited ranges, a departure of the theory of the way other species are supposed to have persisted during the event.

Before K-PG, the earth was a warm and flourishing planet with lush forests and various ecosystems on earth and in the oceans. The dinosaurs were widespread, diverse and dominant. Marine reptiles patrolled the seas and the pterosaurs climbed in the sky. The future humans were still creatures living in the form of a musagaine, part of a small but growing of evolutionary experience in placental mammals.

An asteroid of more than six miles in diameter, moving around 43,200 miles per hour, struck the region of chicxulub of Yucatán, Mexico, releasing an incomprehensible 10²³ Energy joules. For the context, if each explosive that humans have ever exploded immediately, it would still not approach the energy published by the chicxulub asteroid.

A radius of forest of 1,000 miles was instantly cremated by extreme heat, because the impact searched a crater over 100 miles wide and 12 miles deep. The tsunamis, almost the height of the Eiffel tower, spread outwards, ravaging the shores and sea floors around the world, and sounded the mantle of the earth like a bell, triggering what today would be mega-states in the city higher than magnitude 10.

And just when the worst seemed to be finished, it still worsened. The ejected debris of the impact which had exceeded the atmosphere of the earth began to rain. Overheated at the start of the school year, he trampled on the planet with a deadly shower of melted projectiles that triggered world fires.

Vast amounts of soot, dust and aerosols have been left in persistence in the stratosphere, blocking sunlight and plunging the planet into a “winter of impact” with global fall temperatures. Without photosynthesis, vegetable life began to die and the food chains of the smallest ocean plankton with the greatest dinosaurs were erased. Acid rains, produced by rocks rich in vaporized sulfur, have induced rapid changes in ocean chemistry, which led to the generalized extinction of plankton, ammonites and many marine reptiles.

At the end, 75% of species, products of billions of years of evolution, had disappeared. It is a wonder that everything has survived the event, but life has found a means.

In the study, “the night lizards have survived the mass extinction of the Cretaceous – paleogenic near the impact of asteroids”, published in Biology lettersThe researchers combined phylogenetic dating with reconstruction of ancestral features to determine whether the XantUsiid lizards were born before the K-PG border and to identify the characteristics that could have helped their survival.

The genetic data of 34 species of living nightlife lists, integrated into fossils ranging from early Cretaceous to Miocene strata across North America, Central and Cuba, anchored the analyzes.

The genetic clocks have traced Cricosaura Typica, a Cuban species, in the first branch of the family tree, separating before its north and central cousins ​​arrive. The species of Lepidophyma and Xantussia were diversified much later, in parallel radiation approximately 12 million years ago, long after the asteroid reshaped their ancestral landscape.

On the California islands, the lizard of the night of the giant island evolved from a continental line which dispersed west approximately 10 million years ago, crossing temporary terrestrial bridges before becoming isolated.

The researchers discovered that the 34 species of living nocturnal lists descended from at least two old lines that started around 92 million years ago and survived the K-PG border. Unlike survivors among birds or mammals, these lizards have continued a life strategy with relatively small ranges.

Statistical reconstruction estimated that ancestral females produced about two descendants at a time, a figure delimited by the cicosaura egg claws and the most prolific broods observed in more full -bodied island species. The size of the body and fertility always move in tandem through the line, which suggests that larger rails have evolved later, perhaps in response to the island’s habitats.

The authors argue that the persistence of the night lizards through the extinction event of the Cretaceous – paleogenic troubles the hypotheses on the armor lines of the annihilation lines. Survival did not depend on large geographic ranges or large broods, qualities often credited in mammals and birds. Instead, the night lizards seem to have crossed the extinction threshold while occupying close habitats and producing only one or two descendants by breeding event.

Due to the intensity of K-PG, there can be no direct fossil evidence that the night lizards of the Cretaceous (or anything else) occupied the region of immediate impact. Instead, the inference of proximity is based on ancestral ranges reconstructed in North America and central and a molecular dating placing their common ancestor in the upper Cretaceous. Together, this offers indirect evidence of a seat at the forefront for the most devastating event in the history of the earth.

The ideas of the survival of these lizards can refine how scientists project which species are likely to resist rapid environmental changes, especially since the extinction of current mass and managed by humans is accelerating.

© 2025 Science X Network