Research Spotlight: Texas dinosaur reveals new biology

Paluxysaurus jonesi skeletal mountThe Early Cretaceous sauropod Paluxysaurus jonesi weighed 20 tons, was 60 feet long and had a neck 26 feet long, according to the scientists who have prepared the world’s first full skeletal mount of the dinosaur.

The massive mount, prepared for the Fort Worth Museum of Science and History in Fort Worth, was unveiled Nov. 20 when the museum opened in a new $80 million facility. It enables Texans to see their state dinosaur in three dimensions for the first time.

The reconstructed skeleton is yielding clues to the biology of the animal and its relationship to other similar dinosaurs, says Dale Winkler, lead consultant for anatomy and posture on the skeletal mount. Winkler is director of SMU’s Shuler Museum of Paleontology and a research professor in the Roy M. Huffington Department of Earth Sciences, Dedman College.

Winkler has worked with Paluxysaurus bones since crews from SMU and the Fort Worth museum began to unearth them in the early 1990s. The bones assembled for Fort Worth’s Paluxysaurus mount were recovered by students, faculty, staff and hundreds of volunteers over the past 16 years.

In preparing the mount, Winkler said he was surprised at how extremely long the neck was – at 26 feet – compared to the tail, and he found the head especially striking.

“It was really exciting to see what the head looked like,” Winkler says. “Paluxysaurus had very high cheeks compared to its relatives. Once the bones defining the opening of the nose were connected, it showed that the nostrils were turned up on top of the snout, instead of out like Brachiosaurus.”

A relative of Brachiosaurus and Camarasaurus, Paluxysaurus lived about 110 million to 115 million years ago. The dinosaur was identified and named in 2007 by Peter J. Rose. The Fort Worth skeleton was assembled from a combination of actual fossil bones from at least four different dinosaurs found on private ranch land in North Central Texas and from cast lightweight foam pieces modeled on original bones. The mount enables scientists to better understand the animal’s anatomy, size and stature on questions like “How were the legs situated, and how did the shoulders relate to the hips?”

From the skeletal mount, the scientists learned that Paluxysaurus was more than 6 feet wide and nearly 12 feet tall at the shoulder, although built fairly light, Winkler says. Its teeth are a lot slimmer than those of its closest relatives, indicating Paluxysaurus gathered and processed food differently, using its teeth not for chewing, but to grab food, he says.

Paluxysaurus had a long neck like Brachiosaurus, and a tail almost as long, but wasn’t quite so gigantic. Scientists also learned Paluxysaurus had relatively long front arms, making its back more level. The dinosaur’s shoulder turned out fairly high, and the hips were wide, Winkler says, and it had reached a more advanced stage of evolution than Late Jurassic sauropods.

Paluxysaurus’ massive pelvis and its sacrum have never before been viewed by the public, he says. Its ilium, the largest bone in the pelvis, is similar to that of titanosaurids of the Late Cretaceous, mainly found in South America. However, one titanosaurid, called Alamosaurus, entered North America and is known from Big Bend National Park in southwest Texas.

(Above, the skeletal mount of Paluxysaurus jonesi. Photo courtesy of Ralph Lauer Images.)

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