Sat Oct 25 20:40:00 UTC 2025: News Article:
Dinosaur Diversity Thrived Until Asteroid Strike, New Mexico Find Suggests
SAN JUAN BASIN, NM – A groundbreaking study of fossils in the San Juan Basin is challenging the long-held belief that dinosaurs were already in decline before the catastrophic asteroid impact 66 million years ago. Researchers analyzing the Naashoibito Member site in northwestern New Mexico have found evidence of a thriving, diverse dinosaur ecosystem just prior to the mass extinction.
The study, published in the journal Science, reveals that dinosaurs were “doing great” and “thriving” right up to the point of the asteroid strike, according to lead author Andrew Flynn of New Mexico State University. This discovery challenges the idea that a gradual decline in dinosaur diversity made them more vulnerable to extinction.
Unlike the well-studied Hell Creek Formation in Montana, Wyoming, and the Dakotas, which lacked evidence of long-necked sauropods, the Naashoibito Member site boasts fossils of Alamosaurus, one of the largest sauropods to ever exist. This suggests distinct dinosaur communities existed in different regions of North America in the late Cretaceous period.
The research team meticulously dated rock layers using magnetic field comparisons and radiometric dating of sand grains. Their findings place the dinosaur fossils within a 380,000-year window just before the extinction event.
“I can imagine the scene, one minute a jet plane-sized dinosaur was shaking the ground as it walked, the next minute the whole Earth was shaking with the energy unleashed by the asteroid,” co-author Steve Brusatte said.
Experts caution that the New Mexico site provides data from only one location, but the findings have been met with both excitement and some disagreement within the paleontological community. Darla Zelenitsky of the University of Calgary believes the findings may change how researchers think about dinosaurs.
The Naashoibito site offers a unique glimpse into the final days of the dinosaurs. As Brusatte notes, the sudden extinction serves as a reminder that “sudden climate and environmental change can catch animals and ecosystems unaware, and can defeat even the strongest and most iconic of species.”
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