Big Bend National Park

Sauroposeidon

Official State Dinosaur of Texas

by Tristan Smith

In a state where everything bigger is better, it comes as no surprise that Sauroposeidon, the state dinosaur (adopted June 19, 2009), is the tallest ever. While not the biggest overall, it gives the Argentinosaurus a run for its money in weight and length. The fossil record for this behemoth is relatively scant; however, you can see first-hand the impact this giant made in Glen Rose at Dinosaur Valley State Park.

Sauroposeidon existed near the end of the Early Cretaceous, from around 113 to 110 million years ago. It lived along the Gulf of Mexico, which then washed through Oklahoma. Its head could reach up to 69 feet in height and stretch up to 112 feet in length. Examination of the bones revealed they are thin and honeycombed with tiny air cells, much like the bones of an ostrich, making the neck lighter and easier to lift. However, at over sixty tons, Sauroposeidon ranks among the largest dinosaurs ever.

In May 1994, bloodhound trainer Bobby Cross was training his dogs and looking for arrowheads and small relics in the woods of Atoka County, Oklahoma. Stumbling across some fossils, he called the University of Oklahoma Natural History Museum. A team from the University of Oklahoma, led by paleontologist Richard L. Cifelli, uncovered three full vertebrae and two-thirds of a fourth. An extrapolation resulted in an estimated 39-foot-long neck, the longest ever discovered.

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Dinosaur Valley State Park 1629 Park Road 59 Glen Rose, TX 76043 (254) 897-4588 Mon.-Sun. 8 am-5 pm tpwd.texas.gov/stateparks/dinosaur-valley

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Initially, the fossils were believed to be too large to be animal remains and instead noted they were likely petrified tree trunks. Cifelli had the fossils stored until 1999, when he gave them to a graduate student to analyze. Upon further inspection, they realized the significance of their find and went public. It was given the name Sauroposeidon, named for the Greek sea god who is also associated with earthquakes, referring to the ground-shaking that resulted from this dinosaur’s every step.

In 2012, numerous other sauropod remains, known for decades under a variety of names, got shuffled under the genus Sauroposeidon, including Paluxysaurus jonesi, then Texas’ state dinosaur. Sauropod bones and trackways had long been known, as early as 1908, from the Paluxy River area, particularly from the Glen Rose Formation. A bonebed was discovered in nearby Hood County where subsequent work by teams from Southern Methodist University, Tarleton State University, and the Fort Worth Museum of Science and History resulted in the discovery of a sauropod species named Paluxysaurus jonesi.

The teams found a partial skull specimen, featuring an associated left maxilla, nasal, and teeth. Other bones discovered included a partial neck of seven vertebrae, thirteen from the back, and thirty from the tail, with some examples of all limb and girdle bones minus some of the head and foot. A reanalysis of these specimens in 2012 concluded that Paluxysaurus was the same animal as Sauroposeidon, rolling them together and providing the name change we have today. In 2009, it replaced another Sauropod, the Pleurocoelus (which had been adopted in 1997), which was originally thought to have made the prints at the Glen Rose site, as the official Lone Star state dinosaur.

(left) A giant sauropod | Courtesy Daniel Eskridge - Adobe Stock

(top right and bottom right) Tracks exposed due to recent drought reveal Sauroposeidon in Glen Rose. | Courtesy Paul Baker/ LDL Friends Dinosaur Valley State Park