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Did Killing off the Dinosaurs Take More than Rocks from Space?

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What wiped out the dinosaurs? A meteorite plummeting to Earth is only part of the story, a new study suggests. Climate change triggered by massive volcanic eruptions may have ultimately set the stage for the dinosaur extinction, challenging the traditional narrative that a meteorite alone delivered the final blow to the ancient giants. That’s according to a study published in Science Advances, co-authored by Don Baker, a professor in McGill University’s Department of Earth and Planetary Sciences ( https://www.science.org/doi/10.1126/sciadv.adg8284 ).

The research team delved into volcanic eruptions of the Deccan Traps—a vast and rugged plateau in Western India formed by molten lava. Erupting a staggering one million cubic kilometers of rock, it may have played a key role in cooling the global climate around 65 million years ago.
The work took researchers around the world, from hammering out rocks in the Deccan Traps to analyzing the samples in England and Sweden.
In the lab, the scientists estimated how much sulfur and fluorine was injected into the atmosphere by massive volcanic eruptions in the 200,000 years before the dinosaur extinction.
Remarkably, they found the sulfur release could have triggered a global drop in temperature around the world—a phenomenon known as a volcanic winter.
“Our research demonstrates that climatic conditions were almost certainly unstable, with repeated volcanic winters that could have lasted decades, prior to the extinction of the dinosaurs. This instability would have made life difficult for all plants and animals and set the stage for the dinosaur extinction event. Thus our work helps explain this significant extinction event that led to the rise of mammals and the evolution of our species,” said Prof. Don Baker.

AR #101

Facing the Extinction Threat

by William B. Stoecker

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Giant Jurassic Bug in Arkansas Walmart

A giant insect plucked from the façade of an Arkansas Walmart has set historic records. The Polystoechotes punctata or giant lacewing is the first of its kind recorded in eastern North America in over 50 years — and the first record of the species ever in the state. 

The giant lacewing was formerly widespread across North America, but was mysteriously extirpated from eastern North America by the 1950s. This discovery suggests there may be relic populations of this large, Jurassic-Era insect yet to be discovered, explained Michael Skvarla, director of Penn State’s Insect Identification Lab.
Skvarla found the specimen in 2012, but misidentified it and only discovered its true identity after teaching an online course based on his personal insect collection in 2020. He recently co-authored a paper about the discovery in the Proceedings of the Entomological Society of Washington.

“I remember it vividly, because I was walking into Walmart to get milk and I saw this huge insect on the side of the building,” said Skvarla, who was a doctoral student at the University of Arkansas at the time. “I thought it looked interesting, so I put it in my hand and did the rest of my shopping with it between my fingers. I got home, mounted it, and promptly forgot about it for almost a decade.”

It wasn’t until the COVID-19 pandemic that the giant lacewing would find its time to shine. In the fall of 2020, with the world in lockdown, Skvarla was teaching Entomology 432: Insect Biodiversity and Evolution at Penn State. He taught the lab course via Zoom, with students following along remotely on loaner microscopes, and used his own personal insect collection as specimen samples.

As he went to demonstrate the features of a specimen he had previously labeled an “antlion,” Skvarla noticed that the characteristics didn’t quite match those of the dragonfly-like predatory insect. Instead, he thought it looked more like a lacewing. A giant lacewing has a wingspan of roughly 50 millimeters, which is quite large for an insect, a clear indicator that the specimen was not an antlion, as Skvarla had mistakenly labeled it. The students got to work comparing features — and a discovery was made, live on Zoom.

“We were watching what Dr. Skvarla saw under his microscope and he’s talking about the features and then just kinda stops,” said Codey Mathis, a doctoral candidate in entomology at Penn State. “We all realized together that the insect was not what it was labeled and was in fact a super-rare giant lacewing. I still remember the feeling. It was so gratifying to know that the excitement doesn’t dim, the wonder isn’t lost. Here we were making a true discovery in the middle of an online lab course.”

For additional confirmation, Skvarla and his colleagues performed molecular DNA analyses on the specimen. Since confirming its true identity, Skvarla has deposited the insect safely in the collections of the Frost Entomological Museum at Penn State, where scientists and students will have access to it for further research. 

AR #125

One-Hundred-Million-Year-Old Protein

By Nicholle Wahl