Science

First Jurassic vertebrate fossils discovered in Texas

Stexosaurus plesiosaurus

Scientists from the University of Texas at Austin have discovered the first known fossils of a Jurassic vertebrate in Texas, specifically of plesiosaurs, in the Malone Mountains in West Texas. These fossils fill a large gap in the Texas fossil record, which was once dominated by marine invertebrates. Artist’s interpretation of a Jurassic plesiosaur.

A team led by scientists from the University of Texas at Austin has unveiled the first-ever device Jurassic Vertebrate fossils have been discovered in Texas, filling a major gap in the state’s paleontological history.

Unearthed from the limbs and spines of plesiosaurs, these ancient bony remains provide a glimpse into the prehistory when this extinct sea creature navigated the shallow waters of present-day northeastern Mexico and far west Texas some 150 million years ago. years ago.

The bones were discovered in the Malone Mountains in West Texas during two fossil-hunting expeditions led by Steve May, a research associate at the Museum of Earth History at the Jackson School of Geosciences at the University of Texas Austin.

Prior to the discovery, the only Jurassic fossils collected and described from the Texas outcroppings were from marine fossils. invertebratessuch as ammonites and snails. May said the new fossil finds are strong evidence for the presence of Jurassic bones here.

People, there is the Jurassic period vertebrates “There is,” May said. “We’ve found some of them, but there’s more to be discovered that can tell the story of what this part of Texas was like during the Jurassic period.”

Steve May and Lisa Boucher

Steve May (left) and Lisa Boucher carry Jurassic fossils from the Malone Mountains in West Texas among the vaults of the Vertebrate Paleontology collections at the University of Texas at Austin, where the fossils are now kept. It may bear part of the vertebrae of a plesiosaurus. Boucher holds a piece of petrified wood. May and Boucher co-authored a recent paper on the first Jurassic vertebrates found and described in Texas. Source: Jackson School of Geosciences/University of Texas at Austin

A paper describing the bones and other fossils was published in Rocky Mountain Geology On June 23rd.

The Jurassic period was an iconic era of prehistory when giant dinosaurs walked the earth. The only reason we know about them, and other Jurassic life, is because of the fossils they left behind.

But to find Jurassic fossils, you need Jurassic rocks. Because of Texas’ geological history, the state rarely has any outcrops from this time in Earth’s history. The 13 square miles of Jurassic rock in the Malone Mountains make up most of that rock in the state.

In 2015, when May learned while researching a book that there were no Jurassic bones in the fossil record in Texas, he decided to go to the Malone Mountains to explore.

“You don’t want to believe there are no Jurassic bones in Texas,” May said. “In addition, there was tantalizing evidence.”

plesiosaurus fossil

Steve May, research associate at the Jackson School of Geosciences, holds a fossil of a plesiosaurus, an extinct marine reptile. The fossil is among the first Jurassic vertebrate fossils ever discovered and described in Texas. Source: Jackson School of Geosciences/University of Texas at Austin

The clue was the reference to large bone fragments in a 1938 paper on the geology of the Malone Mountains written by Claude Albriton, who later became a professor of geology at Southern Methodist University (SMU). It was enough to take May and his collaborators out to West Texas to see for themselves. Large bone fragments are what they found. Pliziosaurus fossils are being eroded and disintegrated.

It’s a start that could lead to more science, said Louis Jacobs, co-author and professor emeritus at SMU.

“Geologists will go out there looking for more bones,” Jacobs said. “They will find it, and they will look for other things that interest them in their own ways.”

Today, the Malone Mountains rise above the parched desert landscape. During the Jurassic period, sediments were deposited just below sea level, perhaps miles offshore.

The team found many other specimens that give insight into the ancient shallow marine environment, such as fossilized driftwood filled with burrows of marine worms, oyster shells, snails and ammonites. The researchers found a group of plant fossils, including a pinecone, and wood with possible growth rings.

Malone Mountains

Malone Mountains in West Texas. Texas has very few Jurassic rock outcrops. Most of them are in Malone. credit:
Joshua Lively

Jurassic plant fossils found at low latitudes near the Earth’s equator are relatively rare globally, said co-author Lisa Boucher, paleobotanist and director of the Laboratory of Invertebrate Paleontology at the Jackson School. She said the plant discoveries should make the Malone area an interesting place for paleobotanists and those interested in paleoenvironmental reconstructions.

Scientists have been researching the Malones area for more than 100 years. So why did it take so long to return Jurassic bones? May has many ideas – from the remoteness and permissiveness of the area, to the research interests of previous scientists. Whatever the reasons, Boucher said the team’s discovery of Texas first shows the value of fieldwork — as simple as traveling somewhere to see what’s out there.

“It’s often part of the scientific process,” Boucher said. “There’s a few lines buried in an old post, and you’d think someone must have looked into that already, but more often than not they haven’t. You need to dig deeper.”

Reference: “A Record of Late Jurassic Vertebrates from Texas” by Stephen R. May, and Kenneth S. Bader, and Lisa D. Boucher, and Louis L. Jacobs, and Joshua R. Lively, and Timothy S. Myers, and Michael J. Paulsen, June 1, 2023, Rocky Mountain Geology.
DOI: 10.24872/rmgjournal.58.1.19

Additional study co-authors are Kenneth Bader, laboratory director at the Jackson School Museum of Earth History; Joshua Lively, Curator of Paleontology at Utah State University and Jackson School alumnus; and Timothy Myers and Michael Paulsen, both researchers at Southern Methodist University.




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