Dinosaurs were thriving before the asteroid hit, new analysis suggests

New dating of a New Mexico fossil site counters idea that dinos were already on the decline

An illustration of the final days of dinosaurs, with a large long-necked dinosaur rearing up, other dinos running in the background and a streak of light from an asteroid crashing to Earth.

Alamosaurus sanjuanensis (illustrated) was a sauropod found among some of the last dinosaurs in what is today New Mexico. The rock formation that houses its fossils has been re-dated to the late Cretaceous Period, just a few hundred thousand years before asteroid impact.

Natalia Jagielska

A ridge of rocks in New Mexico holds a snapshot of a dinosaur heyday.