Register for an account

X

Enter your name and email address below.

Your email address is used to log in and will not be shared or sold. Read our privacy policy.

X

Website access code

Enter your access code into the form field below.

If you are a Zinio, Nook, Kindle, Apple, or Google Play subscriber, you can enter your website access code to gain subscriber access. Your website access code is located in the upper right corner of the Table of Contents page of your digital edition.

The Sciences

What If the Most Basic Thing We Know About Dinosaurs Is Wrong?

A proposal ditches the traditional dino family tree.

DSC-B0218 07
Gabriel Lío

Newsletter

Sign up for our email newsletter for the latest science news

For the Past 130 years, paleontologists divided dinosaurs into two groups, based on a handful of anatomical features — a split they believe occurred early in the animals’ evolution more than 230 million years ago. The “lizard-hipped” saurischians comprised meat-eating theropods such as T. rex and long-necked, herbivorous sauropodomorphs, such as Diplodocus. On the other side of the divide, “bird-hipped” ornithischians included beaked plant-eaters such as Triceratops.

In March, however, Nature published a proposal that trashes the traditional family tree. Instead, researchers placed theropods with ornithischians, forming a group called Ornithoscelida, and put sauropodomorphs with the early and primitive herrerasaurs.

“Our new hypothesis has lots of exciting implications about when and where dinosaurs may have originated, as well as when feathers may have evolved,” says University of Cambridge paleontologist Matthew Baron, lead author of the study.

Not all researchers are so enthusiastic: A number of early dinosaur evolution experts have challenged the proposed reorganization. But even some of the critics are open-minded.

“I don’t think we can be quite sure whether the new or the traditional arrangement is correct,” says Steve Brusatte of the University of Edinburgh, “but new fossils will hopefully help us untangle it.”

Baron and colleagues aren’t waiting for new fossils to be found, however. In August, they published a reanalysis of Chilesaurus in Biology Letters. The dinosaur, first described in 2015 as a bizarre, herbivorous theropod, is actually a primitive ornithischian, according to the study — a placement that would strengthen the authors’ argument for rewriting the entire family tree.

2 Free Articles Left

Want it all? Get unlimited access when you subscribe.

Subscribe

Already a subscriber? Register or Log In

Want unlimited access?

Subscribe today and save 75%

Subscribe

Already a subscriber? Register or Log In