For decades, paleontologists have debated whether the dinosaurs’ reign was already waning before that fateful asteroid slammed into Earth 66 million years ago. Were these ancient giants fading away, victims of gradual climate shifts and dwindling diversity — or were they thriving right up to the end, undone only by a sudden cosmic catastrophe?
A new study from New Mexico State University tips the scales toward the latter. Led by Dr Andrew Flynn, researchers examined a rock formation in New Mexico known as the Naashoibito Member and used two dating techniques — argon isotope analysis and magnetic polarity alignment — to pin down its age. Their findings suggest that the youngest dinosaur fossils in that formation were deposited no more than 350,000 years before the extinction event. That’s the geological equivalent of a blink.
“I think based on our new study that shows that, at least in North America, they weren’t going towards extinction,” said Flynn, as quoted in The Guardian.
The results challenge the long-held view that dinosaur diversity was tapering off in the late Cretaceous. Instead, the evidence from New Mexico paints a picture of vibrant ecosystems filled with an array of species — from the colossal, long-necked Alamosaurus to crested duck-bills and the ever-dominant T. rex. According to co-author Prof Steve Brusatte, there was no sign that these animals were “in any trouble” before the impact.
Flynn’s team also points out that the perceived decline might be more of an artifact of the fossil record than a biological reality. Rocks from the very end of the Cretaceous are rarer and less exposed, meaning fewer fossils survive to tell their story.
Not everyone is ready to call the debate settled. Prof Michael Benton of the University of Bristol, while calling the discovery “very exciting,” noted that this work covers only one locality. Broader data still suggest that dinosaur species in western North America fell from around 43 to 30 in the last few million years of the Cretaceous. Diversity may have varied by region, with some environments still teeming with life while others began to empty out.
Still, the new evidence from the Naashoibito Member underscores one striking truth: if not for that asteroid, dinosaurs might have kept dominating Earth’s ecosystems for millions more years. The universe, it seems, didn’t end their story because they were weak — it simply rolled the dice, and they were in the wrong place at the wrong time.