Scientists describe the most famous Jurassic vertebrate fossil found in Texas

A team led by scientists at The University of Texas at Austin has filled a major gap in the state’s archeological history—by describing the best-known Jurassic vertebrate fossils in Texas.

The damaged bone fragments come from the legs and spine of a plesiosaur, an extinct marine reptile that would have swam in the deep seas off northeastern Mexico and western Texas 150 million years ago.

The bones were found in the Malone Mountains of West Texas during two archaeological missions led by Steve May, a researcher at UT Austin’s Jackson School of Geosciences Museum of Earth History.

Before the discovery, the only fossils from the Jurassic that had been collected and described from the land in Texas were from marine animals, such as ammonites and snails. May said the new fossils are definitive proof that Jurassic fossils are here.

“Folks, there are Jurassic vertebrates out there,” May said. “We found some of them, but there’s a lot more we can find that will tell us the story of what this part of Texas was like during the Jurassic.”

A paper describing the bones and other fossils was printed inside Rocky Mountain Geology on June 23.

The Jurassic was the famous period of history when giant dinosaurs roamed the earth. The only reason we humans 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’ long history, the state has no traces from this time in Earth’s history. The 13 square miles of Jurassic rocks in the Malone Mountains make up the largest rock formation in the state.

In 2015, while researching a book, May learned that there were no Jurassic bones in the Texas archives, and decided to go to the Malone Mountains to search.

“You don’t want to believe there aren’t Jurassic fossils in Texas,” May said. “In addition, there was a surprising amount of information.”

The clue was the mention of large bone fragments in a 1938 paper on the geology of the Malone Mountains by Claude Albritton, who later became a professor of geology at Southern Methodist University (SMU). It was enough for May and his crew to travel to West Texas to see for themselves. They found large bones. Plesiosaur fossils are eroded and broken. But it’s a start that could lead to more science, said co-author Louis Jacobs, professor emeritus at SMU.

“Geologists have gone there to look for more bones,” Jacobs said. “They’re going to find them, and they’re going to look for things that appeal to them in their own unique ways.”

Today, the Malone Mountains rise above the dry desert. During the Jurassic period, the sediments were deposited under seawater perhaps kilometers from the coast.