First Jurassic vertebrate fossils found in Texas

Scientists at The University of Texas at Austin, led by a team of researchers, have made a significant breakthrough in Texas’s fossil record by uncovering the first-ever Jurassic vertebrate fossils in the state.

These fossil fragments consist of weathered bones from the limbs and backbone of a plesiosaur, an extinct marine reptile that inhabited the shallow sea covering present-day northeastern Mexico and parts of western Texas approximately 150 million years ago.

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

Prior to this discovery, the only documented fossils from the Jurassic period found in Texas were those of marine invertebrates like ammonites and snails. May emphasized that these new findings provide compelling evidence of the existence of Jurassic vertebrates in the region.

“Good news, everyone! We have Jurassic vertebrates right here,” declared May. “While we have found some of them already, there is still much more to be discovered, which can provide us with invaluable insights into the Jurassic era in this part of Texas.”

A paper detailing the bones and other fossils was recently published in Rocky Mountain Geology on June 23rd.

Steve May, a research associate at the Jackson School of Geosciences, holds a fossil from a plesiosaur, an extinct marine reptile. Credit: Jackson School of Geosciences/The University of Texas at Austin.

The Jurassic period stands out as a renowned era in prehistoric times, characterized by the presence of colossal dinosaurs that roamed the planet. Our knowledge of these remarkable creatures and other life forms from the Jurassic period is solely attributable to the fossils they left behind.

However, locating fossils from the Jurassic era necessitates the discovery of rocks from the same geological period. Unfortunately, due to Texas’s geological history, the state possesses very few exposed rock formations dating back to this specific period. The Malone Mountains, spanning an area of approximately 13 square miles, contain the majority of these rare Jurassic rocks found within the state.

In 2015, during his research for a book, May stumbled upon the disheartening realization that the Texas fossil record lacked any evidence of Jurassic bones. Determined to investigate further, May embarked on an exploration expedition to the Malone Mountains.

“It’s difficult to accept the notion that there are no Jurassic bones in Texas,” expressed May. “Additionally, there was a captivating clue that urged me to pursue this further.”

The Malone Mountains of West Texas. Texas has very few outcrops of Jurassic rocks. Most of them are in the Malones. Credit: Joshua Lively

The breakthrough came in the form of a clue mentioned in a 1938 paper by Claude Albritton, a geology professor at Southern Methodist University (SMU), regarding the presence of significant bone fragments in the geological study of the Malone Mountains. This clue served as a catalyst for May and his collaborators to venture to West Texas and personally investigate the matter. Their efforts were rewarded when they discovered substantial bone fragments, which turned out to be the fossils of plesiosaurs. Although these fossils have suffered erosion and fragmentation over time, they mark a promising starting point that holds the potential for further scientific discoveries, as emphasized by co-author Louis Jacobs, a professor emeritus at SMU.

Jacobs stated, “Geologists will venture to the area in search of additional bones. They will uncover them and explore other intriguing aspects in their own unique ways.”

Today, the Malone Mountains tower over the arid desert landscape. During the Jurassic period, sedimentary layers were deposited just below sea level, likely within a short distance from the shoreline.

Source: University of Texas at Austin

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