We have completed maintenance on DiscoverMagazine.com and action may be required on your account. Learn More

#35: Fossil Stirs Debate Over 
Dinosaurs’ Last Days

When exactly did the dinosaurs depart?

By Ed Yong
Dec 22, 2011 6:00 AMNov 12, 2019 5:55 AM
1904 illustration by <a href="http://en.wikipedia.org/wiki/File:Triceratops_-_1904.jpg">Charles R. Knight</a> via Wikipedia | NULL


Sign up for our email newsletter for the latest science news

A horn discovered in southeastern Montana may be the remains of one of Earth’s very last dinosaurs. The fossil, which probably came from a rhinolike Triceratops, has rekindled a long-standing debate about how quickly the dinosaurs went extinct.

Yale University paleontologists Tyler Lyson and Stephen Chester found the horn just 5 inches below the K-T boundary, a thin layer of rock that marks the moment when a large asteroid hit the planet 65 million years ago. Until now, no dinosaur fossils have been confirmed in a nine-foot zone below this line (deeper layers of rock represent earlier times). Many scientists take this “fossil gap” as evidence that dinosaurs gradually declined and were already extinct before the asteroid hit. But Lyson, Chester, and others argue that the extinction was sudden and catas-
trophic, and the new find supports their view. “The horn clearly documents the presence of some dinosaurs right up to the K-T boundary,” Lyson says. “It’s highly likely that the asteroid wiped them out.”

1 free article left
Want More? Get unlimited access for as low as $1.99/month

Already a subscriber?

Register or Log In

1 free articleSubscribe
Discover Magazine Logo
Want more?

Keep reading for as low as $1.99!


Already a subscriber?

Register or Log In

More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Our List

Sign up for our weekly science updates.

To The Magazine

Save up to 40% off the cover price when you subscribe to Discover magazine.

Copyright © 2024 Kalmbach Media Co.