Dinosaurs Thrived in New Mexico Up to Catastrophic End Cretaceous Impact

Dinosaurs Thrived in New Mexico Up to Catastrophic End Cretaceous Impact
by Clarence Oxford
Los Angeles CA (SPX) Oct 27, 2025

New radiometric dating from a contested fossil site in New Mexico has established that dinosaurs remained both abundant and regionally varied right up until the Cretaceous asteroid impact sixty six million years ago, according to new research.

The study, conducted by Andrew Flynn and his team, resolves ongoing debates regarding the circumstances of dinosaur extinction. Previously, scientists disagreed on whether dinosaurs faded gradually, leaving them susceptible to the asteroid's aftermath, or if they perished suddenly. These differences largely stemmed from inconsistencies and gaps in fossil records.

Until now, the best chronologically constrained fossil evidence near the Cretaceous Paleogene boundary came from the Hell Creek and Fort Union Formations in the northern Great Plains. Studies in these areas provided conflicting interpretations, with some suggesting a slow decline and others a sudden extinction. Flynn's group applied precision geochronology to the Naashoibito Member of the Kirtland Formation in northern New Mexico, dating the fossil rich rocks to between approximately sixty six point four and sixty six million years ago.

This breakthrough demonstrates that dinosaur fossils from this New Mexico site are contemporaneous with those from the more widely studied Hell Creek Formation. These animals, diverse in size, diet, and species, inhabited the region within about three hundred forty thousand years of the asteroid's impact, displaying no ecological decline prior to extinction.

Furthermore, ecological analysis incorporating the new data indicates that instead of a single uniform dinosaur fauna, there was clear regional diversity throughout western North America until the close of the Cretaceous. Although fossil evidence from other continents is not dated as precisely, it suggests a similar persistence of diverse dinosaur populations until the extinction event.

The authors conclude that non avian dinosaurs were thriving until their abrupt extinction, countering the longstanding notion of a prolonged terminal decline. A related perspective by Lindsay Zanno delves further into the significance of these findings.

Research Report:Late-surviving New Mexican dinosaurs illuminate high end-Cretaceous diversity and provinciality