Utah Paleontologist helps discover a part of pterosaur evolutionary chain

News

SALT LAKE CITY, Utah – A Utah scientist has helped use bones of an existing species of ancient reptile to show they are a relative of the flying pterosaurs that once roamed Utah and the rest of the world’s skies millions of years ago.

Pterosaurs came in all sizes, some were as little as your palm, and others stood taller than a giraffe with a 30-foot wingspan.

Natural History Museum of Utah Curator Randall Irmis helped discover a part of the pterosaurs’ evolutionary chain. The scientists believe they have found an unexplained part of the evolution of the flying reptiles.

The new hypothesis show lagerpetids shared part of the family tree with pterosaurs. They were odd skinny reptiles. After 15 years of studying the fossils, Dr. Irmis and his colleagues around the world realized they were looking at what may have evolved into pterosaurs.

Pterosaurs came on the scene about 220 million years ago, and even though people think they are a dinosaur, they are not. They are different from dinosaurs; their bones are more delicate and harder to preserve; we don’t find many of them in Utah because the water was very energetic and destroyed a lot of the delicate bones. When water is slow-moving it deposits the bones in the sediment and they can be recovered as fossils.

Dr. Irmis said, “They get confused with dinosaurs because they were on the earth at the same time in the same places. They are a different branch of the family tree but share a common ancestor”

The Pterosaurs disappeared 66 million years ago in the mass extinction event that killed off the dinosaurs.

To get a sense of geological time, Ancient Lake Bonneville here in Utah was 30,000 years ago caused by a glacier that damned the outflow of the basin that is now Utah. The pterosaur link the paleontology team discovered was 237 million years ago.

Dr. Irmis explained, “There is a group of reptiles called archosaurs, and they evolved into two distinct branches – one branch leading to crocodiles, and the other leading to dinosaurs and birds.”

No one knew how that happened, Dr. Irmis said, “This new study helps clarify where pterosaurs fit on one of those branches.”

A fossil they discovered as grad students in New Mexico started them on the search to figure out what was happening.

He said, “I was part of a team doing fieldwork in a place called ‘Ghost Ranch’ in New Mexico in 2006. We started when we were all graduate students, and we found a new species of a small reptile called Dromomeron romeri” The species is considered a lagerpetid.

The team first discovered the femur. Then as the dig progressed, they discovered more of the skeleton of the creature. At first, they did not realize the team had discovered a new species, but Dr. Irmis went to Argentina to study similar bones. In that study, they were able to confirm the new creature.

The new hypothesis is the species shares a common ancestor with pterosaurs, which learned to have powered flight. “I think we have a really good hypothesis that is supported by a lot of data.” Dr. Irmis explained, “but it’s always subject to future testing by other paleontologists.”

“We think we have a good explanation of where pterosaurs fit on the reptile family tree. They are on the branch that eventually included dinosaurs, but they are not dinosaurs.”

Dr. Irmis said, “Think about it as an apple tree, and at the base of two branches they meet, and so when we talk about a common ancestor that means, the last species before the two branches started to grow apart from each other.”

The new discovery is more closely related to birds and dinosaurs than they are crocodiles.

There have been reports the discovery was a fuzzy lizard, but Dr. Irmis said that it is a downy covering more related to feathers or the down that is in a pillow. “It just took the right kind of fossil deposits that preserved soft tissue, particularly in Northern China there is a deposit that has preserved soft tissue, and other paleontologists started finding meat-eating dinosaurs with the downy coverings and feathers that suggests most dinosaurs had some covering.”

Dr. Irmis didn’t want it to get confused, “Pterosaurs are completely different than birds, pterosaurs are a flying reptile that has a wing made of their forearm, and a leathery winged membrane attached on their fourth finger, their ring finger.” He continues, ‘that group evolved totally independently of birds –we are talking about two different instances of flight evolving.”

The new hypothesis about the lagerpetid helps explain an evolutionary moment

In a statement from Virginia Tech about the study, “This study is a result of an international effort applying both traditional and cutting-edge techniques,” said Martín D. Ezcurra, lead author of the study from the Museo Argentino de Ciencias Naturales in Buenos Aires, Argentina. “This is an example of how modern science and collaboration can shed light on long-standing questions that haunted paleontologists during more than a century.”

ABC4 News asked Dr. Irmis what made him want to study Dinosaurs? He mentioned he was always fascinated with them and he looks at it that “I was the kid who never grew up!”

Dr. Randall Irmis is absolutely passionate about his studies in paleontology and geology. He asked ABC4 News to remind everyone that the Natural History Museum of Utah has a fantastic dinosaur exhibit and if you want to know more, go see the museum. But remember, because of the pandemic you need to go online to the website to book your tickets in advance and get the time you can see the exhibits. Currently, they are running a learning experience about Antarctic Dinosaurs.

Dr. Irmis explained with a smile, there wasn’t always snow and ice in Antartica.

Click here to download the ABC4 Utah News app for the first alerts on your phone. Sign up for the ABC4 Utah breaking news and daily newsletters.

Copyright 2021 Nexstar Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

ABC4 PODCASTS

More Podcasts