Discovery of predinosaur fossil prompts review of history

Chicago Tribune

This artist’s rendering, provided by the journal Science, depicts four dinosaurs and dinosaur precursors from New Mexico. Scientists now think they coexisted.

Paleontologists have come across the fossil remains of a surprising creature whose existence could rewrite the books on how dinosaurs came to be.

The story as it is being rewritten is that the first dinosaurs on Earth were relatively pint-sized animals and spent 15 million to 20 million years low in the minor leagues of life’s pecking order before they became the world’s dominant animal life form.

That idea runs counter to the prevailing theory that after dinosaurs first evolved, their numbers and their relative size exploded, quickly making them the dominant animal life form on Earth.

The newly discovered fossil that is shaking up old theories of a rapid rise of dinosaur dominance is not a dinosaur but a very close cousin, given the name by its discoverers. It belonged to an archaic group of animals called “basal dinosauromorphs,” or predinosaurs.