Newswise — A groundbreaking achievement has been accomplished by a team of scientists from The University of Texas at Austin as they have bridged a significant gap in the fossil record of the state. For the first time, they have unveiled the existence of Jurassic vertebrate fossils in Texas.
The fossilized bone fragments, weathered by time, originate from the limbs and backbone of a plesiosaur—a prehistoric marine reptile that once inhabited the shallow seas covering present-day northeastern Mexico and far western Texas approximately 150 million years ago.
Unearthing these bones was the result of 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 known fossils from the Jurassic period found in Texas consisted of marine invertebrates such as ammonites and snails. May emphasizes that these newfound fossil remains provide concrete evidence that Jurassic vertebrates existed in the area.
"Everyone, it is now confirmed that Jurassic vertebrates existed here," May declared. "While we have uncovered some of them, there is still more to be revealed, which will enlighten us about the ancient environment of this region during the Jurassic era."
The bones and other fossils have been meticulously detailed in a scientific paper published in Rocky Mountain Geology on June 23.
The Jurassic period holds an esteemed place in prehistoric history, characterized by the presence of colossal dinosaurs that roamed the Earth. Our knowledge of these magnificent creatures and other life forms from that era stems from the fossils they left behind.
However, uncovering Jurassic fossils necessitates the existence of rocks from that specific time period. Unfortunately, due to the geological evolution of Texas, there is a scarcity of outcrops from the Jurassic period. The Malone Mountains, encompassing approximately 13 square miles of Jurassic-aged rocks, comprise the majority of such formations in the state.
In 2015, while conducting research for a book, May stumbled upon the disheartening realization that there were no Jurassic bones recorded in the Texas fossil archives. Motivated to explore further, he embarked on an expedition to the Malone Mountains.
"The notion of Texas lacking Jurassic bones is difficult to accept," May expressed. "Moreover, there was an intriguing clue."
The clue emerged from a 1938 paper on the geology of the Malone Mountains by Claude Albritton, who later became a geology professor at Southern Methodist University (SMU). Albritton's work briefly mentioned the presence of large bone fragments, which served as a promising lead that impelled May and his collaborators to venture to West Texas. Their search indeed yielded large bone fragments, although the plesiosaur fossils they discovered had suffered erosion and fragmentation.
Nonetheless, this discovery marks the beginning of a potential scientific breakthrough, as stated by co-author Louis Jacobs, a professor emeritus at SMU.
Jacobs stated that geologists will venture out to search for additional bones. He expressed confidence in their ability to discover these fossils and explore other intriguing aspects in their own unique ways.
In the present day, the Malone Mountains tower over the arid desert terrain. During the Jurassic period, sediments settled just below sea level, likely within a few miles of the coastline.
The team uncovered several other specimens that provide insights into the ancient shallow marine ecosystem. They encountered petrified driftwood riddled with burrows from marine worms, as well as the shells of clams, snails, and ammonites. Additionally, the researchers stumbled upon a variety of plant fossils, including a pinecone and wood exhibiting potential growth rings.
According to co-author and paleobotanist Lisa Boucher, who serves as the director of the Jackson School's Non-Vertebrate Paleontology Lab, Jurassic plant fossils from lower latitudes near the equator are relatively scarce on a global scale. She believes that the plant discoveries in the Malones should attract the attention of other paleobotanists and individuals interested in reconstructing paleoenvironments.
For over a century, scientists have been engaged in research within the Malones. However, the question arises: why did it take such a significant amount of time to uncover Jurassic bones? May proposes several potential explanations, ranging from the remote location and permitting challenges to the specific research interests of previous scientists. Regardless of the reasons, Boucher emphasizes that the recent discovery made by the team in Texas highlights the importance of fieldwork—simply venturing to a location to observe what lies there.
Boucher affirms that this process is a common aspect of scientific inquiry. Sometimes, there are a few fleeting references buried within old publications, leading one to assume that someone has already examined them thoroughly. However, more often than not, such inquiries remain unexplored. Therefore, one must dive deep into these references and investigate them diligently.
The study’s additional co-authors are Kenneth Bader, a laboratory manager at the Jackson School Museum of Earth History; Joshua Lively, the curator of paleontology at Utah State University and a Jackson School alumnus; and Timothy Myers and Michael Polcyn, both researchers at Southern Methodist University.
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