Aurora Ornatus – Did Dinosaurs Enjoy That Light Show In The Sky?

The Anchiceratops probably enjoyed watching the brilliant show put on by the Aurora Borealis as much as humans do today, but it’s hard to imagine how they viewed the atmospheric event. Did they think of it as the work of god(s) in the heavens, or did they view the streaks in the sky as dangerous and scary? There’s really no way of knowing whether dinosaurs felt the same way about natural beauty as we humans, and since…

The Fireball That Killed the Dinosaurs Could Help Us Find Life on Other Planets

When David Kring of the University of Arizona gave a presentation at the Lunar and Planetary Science Conference in 1991, he didn’t expect a packed crowd for his talk on the petrology of the Chicxulub Structure in the Yucatan, Mexico. Normally, Kring knew, impact-cratering sessions were presented in the smallest room—the miserable Room D, a shoebox on the second floor. But the magnitude of his announcement attracted scientists across fields and disciplines, so he was bumped up to the main room.

Kring had been investigating a place called the Yucatán-6 borehole, and he and his team had discovered shock quartz and impact melt fragments in two thumb-sized bits of rock that were over half a mile beneath the surface of the Earth. This was evidence that the hole, thought for a very long time to be a volcanic center, was actually an impact structure. And not just any “impact structure,” and not just any crater―but the crater of all craters on Earth. The one behind the death of the dinosaurs 66 million years ago.

Last year, Kring was part of an expedition in which scientists drilled into Chicxulub to investigate how the disastrous collision of fireball and Earth that killed the dinosaurs also created the conditions for life to begin anew. Last month, Kring and his colleagues returned to the Lunar and Planetary Science Conference to present their findings from the new core samples they took on that expedition. The results provide new clues about how life may have begun on Earth about 4 billion years ago—and point us towards how and where we can look for life across the universe.


Back in the early 1990s, Kring knew what he was looking for—a crater of the size and magnitude that would provide evidence of catastrophic extinction—but he didn’t know where to look. “It was a race to find the impact site,” Kring tells mental_floss, “and we had made a discovery of this very thick impact ejecta deposit in Haiti, which pointed us to [the Yucatan].”

Impact ejecta is what’s blasted from the Earth or other body when a meteor crashes into it. In this case, a giant chunk of the Earth was blown a thousand miles away. Until the Haiti discovery, people were looking all over the planet for the crater. But now they had a target region. Meanwhile, Petroleos Mexicanos, an oil company, had drilled down into what they thought was a “geophysical anomaly” in the Yucatan―a salt dome, maybe, where there might be oil. That’s when Kring and his colleagues re-examined samples collected from the site and realized there were features consistent with an impact.

That the Yucatan site was still intact to be found wasn’t a given. In the last 65 million years, half of the seafloor has…

Early dinosaur relative sported odd mix of bird, crocodile-like traits

Teleocrater rhadinus
REPTILE REIMAGINED Unlike other known close dinosaur relatives, Teleocrater rhadinus (illustrated) walked on four feet instead of two and had an ankle bone like a crocodile’s.

Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” (Buenos Aires, Argentina), artwork by Gabriel Lio

While researching fossils in a museum in 2007, Sterling Nesbitt noticed one partial skeleton that was hard to place. Though the reptile — at the time, unofficially called Teleocrater rhadinus — was thought to be a dinosaur relative, it was an oddball. At about 2 meters long, it was larger than other close relatives, walked on four feet instead of two, and had an unusually long neck and tail. Since the skeleton was missing some key bones, it was hard to know where the creature, found in Tanzania in 1933, fit within Archosauria, the group that includes crocodiles, birds and dinosaurs.

Nesbitt, himself on the way to Tanzania for a dig, couldn’t shake thoughts of the strange fossil. “It would be nice if we found more,” the vertebrate paleontologist, now at Virginia Tech, remembers thinking.

Now, a decade later, he and colleagues have done just that, discovering three additional partial skeletons of T. rhadinus — including bones missing from the original specimen. The more complete picture of T. rhadinus provides the first good…

Anatomy analysis suggests new dinosaur family tree

new dino evolutionary tree
NEW WAY TO RELATE The dinosaur evolutionary tree just got a makeover. One outcome of the proposed rearrangement is that meat-eating evolved twice in dinosaurs (in groups represented by Tyrannosaurus rex, bottom middle, and Staurikosaurus, right), as did traits associated with plant-eating (groups represented by Brontosaurus, left, and Triceratops, top middle).

The standard dinosaur family tree may soon be just a relic.

After examining more than 400 anatomical traits, scientists have proposed a radical reshuffling of the major dinosaur groups. The rewrite, reported in the March 23 Nature, upsets century-old ideas about dinosaur evolution. It lends support to the accepted idea that the earliest dinosaurs were smallish, two-legged creatures. But contrary to current thinking, the new tree suggests that these early dinosaurs had grasping hands and were omnivores, snapping up meat and plant matter alike.

“This is a novel proposal and a really interesting hypothesis,” says Randall Irmis, a paleontologist at the Natural History Museum of Utah and the University of Utah in Salt Lake City. Irmis, who was not involved with the work, says it’s “a possibility” that the new family tree reflects actual dinosaur relationships. But, he says, “It goes against our ideas of the general relationships of dinosaurs. It’s certainly going to generate a lot of discussion.”

The accepted tree of dinosaur relationships has three dominant branches, each containing critters familiar even to the non–dinosaur obsessed. One branch leads to the “bird-hipped” ornithischians, which include the plant-eating duckbills, stegosaurs and Triceratops and its bony-frilled kin. Another branch contains the “reptile-hipped” saurischians, which are further divided into two groups: the plant-eating sauropods (typically four-legged, like Brontosaurus) and the meat-eating theropods (typically two-legged, like Tyrannosaurus rex and modern birds).

This split between the bird-hipped and reptile-hipped dinos was first proposed in 1887 by British paleontologist Harry Seeley, who had noticed the two strikingly different kinds of pelvic anatomy. That hypothesis of dinosaur relationships was formalized and strengthened in the 1980s and has been accepted since then.

The new tree yields four groups atop two main branches. The bird-hipped ornithischians, which used to live on their own lone branch, now share a main branch with the reptile-hipped theropods like T. rex. This placement…