Meet Chilesauraus, the 'missing link' in dinosaur family tree

In Baron's updated family tree, therapods and ornithischians share a common ancestor, so the mixed traits of Chilesaurus could indicate a transitional species from both groups.
By Alex Bourque | Aug 19, 2017
Paleontologists have taken a second look at a strange two-legged dinosaur discovered a few years ago that had defied classification because of its baffling set of weird characteristics. The findings suggest Chilesaurus could be the "missing link" in the dinosaur family tree.

The study is published in the journal Biology Letters.

Chilesaurus, first described by scientists in 2015 in the journal Nature, roamed what is now southern Chile about 150 million years ago, according to a report by the Los Angeles Times. It walked on two legs and measured about two to three meters long. Its flat teeth suggest the creature was a plant-eater.

Researchers classify dinosaurs by comparing key physical traits. But Chilesaurus perplexed scientists because it did not fit into any dinosaur category. While classified as a therapod, which are mostly carnivores, its flat teeth were useful for eating plants, not flesh.

"It was a bit of a puzzling specimen, really," said co-lead author Matthew Baron, a doctoral candidate in paleontology at Cambridge University, in the Times report.

When Baron analyzed the dinosaur's physical characteristics by comparing them to 457 physical traits he had recently used to revise his dinosaur family tree, he found that Chilesaurus should not be classified as a carnivorous therapod, but as a vegetarian ornithischian.

In Baron's updated family tree, therapods and ornithischians share a common ancestor, so the mixed traits of Chilesaurus could indicate a transitional species from both groups.

Dinosaurs are excellent models for studying life on Earth because their 247-million-year sojourn on the planet is well studied. And because they lived through many turbulent geological events and dramatic changes in temperature, dinosaur fossils can reveal how life adapted over millions of years.

"As well as being really cool museum specimens and movie monsters, dinosaurs are also one of the best groups of organisms that we know of for modeling how life responds to a changing climate," Baron said.

---

Have something to say? Let us know in the comments section or send an email to the author. You can share ideas for stories by contacting us here.

Comments
Comments should take into account that readers may hold different opinions. With that in mind, please make sure comments are respectful, insightful, and remain focused on the article topic.