Not long ago, many experts believed that dinosaurs were already in decline before an asteroid hit Earth 66 million years ago. That strike doomed them to extinction. A new study suggests that the theory isn’t true. The study found a wide range of species present in New World fossil records. All of those fossils dated back to about 350,000 years before the fatal asteroid strike. The 6-to-9-mile-wide space rock struck near what is today known as Mexico. The study was run by a research team from a number of US and British universities. It was published in the journal Science. The research team focused on fossils found in the San Juan Basin in New Mexico. They then compared them with others found in the northwest region of the US. They used two methods to date the New Mexico rocks. One method is to measure the radioactive decay of isotopes inside the rocks. The other is to study the minerals in rocks that can reveal age. “I think based on our new study … that, at least in North America, they weren’t going towards extinction,” lead author Andrew Flynn said in a statement. He is a professor at New Mexico State University. The research team found dozens of dinos in the fossils as rich and diverse as elsewhere in North America. In some samples, they found striking differences within the same species. That could be due to differences in climate. For example, duck-billed dinos in New Mexico had showy crests on their heads. That was not true for their cousins in the North. The region also featured huge long-necked sauropods. They are not found in the North. Some experts have offered other theories for what appears to be a decline in dinos before the asteroid struck. They argue it may be due to gaps in the fossil records. Reflect: What’s something you’ve learned that changed how you see the world or what you believed before? Photo of illustration of a dinosaur from Unsplash courtesy of Fausto García-Menéndez.
