Understanding the timeline of dinosaur extinction: New Mexico's contribution

NEW MEXICO The story of how dinosaurs vanished from Earth continues to evolve, with New Mexico playing a surprising role in reshaping our understanding. Research led by a professor at New Mexico State University is shedding new light on the final chapter of these prehistoric giants.

Most people are familiar with the theory that around 66 million years ago, a colossal asteroid, estimated between six and nine miles wide, struck the area now known as the Gulf of Mexico. This impact initiated the Cretaceous-Paleogene extinction event, which wiped out approximately three-quarters of all species on the planet.

However, scientists are asking deeper questions: Were dinosaurs already in decline before the asteroid struck? Were they losing diversity, or decreasing in population? Could they have survived if this catastrophic event had never occurred?

Species that survive mass extinctions tend to be small, able to burrow, or aquatic, explains Andrew Flynn, Associate Professor of Geological Sciences at New Mexico State University. For more than 14 years, Flynn has been studying dinosaur fossils in the northwestern region of New Mexico, uncovering evidence that challenges the long-held view that dinosaurs were in gradual decline prior to the asteroid impact.

Historically, the Hell Creek Formation, spanning the Dakotas, Wyoming, and Montana, has been the primary source for understanding the late Cretaceous dinosaur population. While valuable, Flynn notes it represents just one snapshot of the broader North American timeline.

Its an important data point, but its only one. Now we have a second, and it tells a very different story, Flynn says. His recent study suggests that dinosaurs were thriving across diverse ecosystems in North America shortly before the extinction event, rather than being on the verge of collapse.

Flynns research also redefines the timeline for certain species in New Mexico, including the Alamosaurus. Previously thought to have existed hundreds of thousands of years earlier than their counterparts in the Hell Creek Formation, these dinosaurs actually lived in the very final stages of the Cretaceous period.

These species existed right before the asteroid struck. For humans, thats a long time, but geologically, its essentially the last dinosaur communities, Flynn explains.

Understanding these dynamics is crucial for insights into extinction-level events. If ecosystems collapse rapidly, even large speciesincluding humanscould face similar risks in the event of a catastrophic global incident.

Flynn emphasizes that New Mexico remains a largely untapped site for paleontological discovery. The San Juan Basin, in particular, holds immense potential for further research into the final era of dinosaurs.

New Mexico is an outstanding place for paleontology. Much of it is still understudied, he notes. While this work is ongoing, the findings already suggest that New Mexico will be key in refining the timeline and ecological context of dinosaur extinction.

Author: Gavin Porter