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World’s first full skeletal mount of Paluxysaurus jonesi dinosaur reveals new biology

The 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 Paluxysaurus jonesi, 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. The Paluxysaurus mount 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 the Shuler Museum of Paleontology at SMU and a research professor in the Roy M. Huffington Department of Earth Sciences. Winkler has worked with Paluxysaurus bones since crews from SMU and the Fort Worth museum began to unearth them in the early 1990s.

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.”

Skeletal mount reveals animal’s anatomy, size and stature
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, unlike Diplodocus, 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.

The bones assembled for Fort Worth’s Paluxysaurus mount were recovered by students, faculty, staff and hundreds of volunteers over the past 16 years.

DFW’s ancient Cretaceous past included dinosaurs along a shallow sea
Most bones were found in masses of hardened sandstone dug from a Hood County quarry on the private ranch of Bill and Decie Jones.

It took more than a decade to remove the specimens because they were embedded in a hard sandstone matrix, said Louis L. Jacobs, a world-renowned paleontologist, dinosaur fossil hunter and a professor in the Earth Sciences department at SMU. Jacobs helped unearth and prepare the bones.

The end result is a skeleton that is “absolutely awe-inspiring,” Jacobs says. “Paluxysaurus and the plants and animals it lived among show us the truly unique position Texas held in the Cretaceous world. The exhibits at the Fort Worth museum tell that story to the people who now live where the giants used to walk.”

Sauropods weren’t common during the Early Cretaceous. The Fort Worth specimen is morphologically distinct from all other sauropods described and named in North America at that time, according to the research of Rose, who is now a doctoral student at the University of Minnesota. Rose identified the type specimen and named the animal while a graduate student in geology at SMU.

The Paluxysaurus dinosaurs lived near the shore of the rising Cretaceous seas that eventually covered Texas, amid large-trunked conifer trees that are now extinct. The semi-arid environment nurtured relatives of sago palms but few flowering plants, which were just beginning to spread out across the Earth, Winkler says.

The scientists say the Jones Ranch bone bed is one of the richest accumulations of sauropod bones in North America.

A group apparently died together there in a common death, perhaps a forest fire, according to earlier research of Winkler and Rose.

The quarry has produced hundreds of bones, all within an area of 400 square meters. Fossil hunters found 60 to 70 percent of the bones needed to reconstruct a single Paluxysaurus skeleton, says Aaron Pan, curator of the Fort Worth museum. Most of the bones, however, are too fragile or deformed to be mounted 15 feet in the air, Pan says.

“We were happy to have as much of it as we do,” Pan says, noting that the museum welcomes fossil researchers. “Most of our material is available. So if a researcher did want to see any of it, we’d be happy to have them come.”

Huge, multi-year project recreated skeleton with bones and casts
Paleontologists from both the museum and SMU helped exhibit fabricator and model-maker Robert Reid Studios, located near Fort Worth, mount the bones. About 15 percent to 20 percent of the skeleton is actual fossil bone, while the remaining bones are casts, says Pan.

Preparing the fossils for mounting and modeling was a huge, multi-year project. The cast bones were computer modeled using laser scanning, says Michael J. Polcyn, director of the Earth Sciences department’s image analysis lab at SMU.

“I was able to scan available bones in 3D and manipulate them in the computer to remove distortion, create mirrored pieces — for example right or left — and model missing portions,” Polcyn says. “I was then able to use the computer models to produce life-sized physical models of the bones using computer-controlled machining techniques.”

Many of the very large bones remain all or partially embedded in blocks of quarry rock, due primarily to the logistical challenge of removing them. For example, the 11-ton block containing the pelvis and sacrum required hoisting with an industrial crane. For some large blocks, tons of rock were painstakingly cut with diamond-blade saws from around the various bones to make them manageable in the SMU labs, Winkler says.

Rock was partially removed from the pelvis and sacrum so that Polcyn could scan them. The scientists then constructed a model using dense foam that was cut to form the basic shape. Crews from Robert Reid Studios coated them with epoxy resin to give them hardness, then added a layer of bone texture and painted them to match.

In the case of the long neck, much was preserved, but many of the bones were distorted by sediment load, which essentially crushed the bone, Polcyn says. He studied the neck vertebrae and made a model. Only two of the skull bones were recovered: the left maxilla and a nasal bone, which defined the top front of the face. Polcyn worked closely with a sculptor to reconstruct the skull by studying related groups of dinosaurs.

Preparation of the skeletal mount was funded by the Fort Worth Museum of Science and History. — Margaret Allen

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Mistaken ID for official Texas state dinosaur; name to change

It’s a case of mistaken dino-identity. The official State Dinosaur of Texas is up for a new name, based on Southern Methodist University research that proved the titleholder has been misidentified.

State Rep. Charles Geren of Fort Worth filed a resolution January 7 to change the name of the state dinosaur from Pleurocoelus to Paluxysaurus jonesi to correctly name the massive sauropod whose tracks and bones litter the central Texas Jones Ranch.

Peter J. Rose is the scientist behind the name change: His master’s level study of dinosaur bones at SMU eventually led him to dispute the long-accepted notion that the large, sauropod bones found in and around the Paluxy River near Glen Rose, Texas, were the same as Pleurocoelus bones first found in Maryland in the late 1800s.

Rose determined it was a different dinosaur altogether — a previously unrecognized genus and species he named Paluxysaurus jonesi, after W.W. Jones, the owner of the land on which the fossils were found. Once Rose’s discovery was published in 2007, Pleurocelus’ grand Texas title no longer fit.

Geren filed his resolution on behalf of constituents at the Fort Worth Museum of Science and History, which is a partner with SMU in ongoing research at the Glen Rose site, about 60 miles southwest of Fort Worth. Aaron Pan, Ph.D., the museum’s curator of science, believes it’s crucial to get the record corrected.

“I think it’s going to be good for Texas paleontology and dinosaur research in general,” Pan said. “Peter Rose’s research has found that it is a new genus and a new species. This dinosaur is unique to Texas, and it is the most abundant dinosaur fossil found in the Glen Rose area.”


SMU geological sciences professor Louis L. Jacobs, who was Rose’s mentor, said that nobody before Rose had made an adequate study of the sauropod bones found at the Glen Rose site. Jacobs has described Texas as a kind of “free trade zone for the age of reptiles” since dinosaurs from three different geologic time periods have been found in three different geographic areas of the state. Paluxysaurus jonesi is believed to have lived 112 million years ago during the Cretaceous Period.

“It just goes to show that Texas is a great place to make great discoveries — even when you might think everything has been found,” Jacobs said.

Rose, 29, received his master’s degree in geological sciences from SMU in 2004. Currently pursuing a Ph.D. in paleontology at the University of Minnesota, he concedes he is excited about the proposal to change the state dinosaur’s name to correspond with his research.

“But when you come down to it, whether it’s a new species is not the big question. More important are some of the bigger picture ideas about how these organisms evolved and what they were doing when they were alive,” Rose said. “I hope the future work I do has some broader implications. Currently I’m doing more climate research with implications, I hope, for global climate change.”

Related links:
News-Journal: “Dino-right! Fix is in for misnamed Texas dinosaur”
DMN: “Legislature may make dinosaur official”
FW Biz Press: “Updated dino exhibit set for science museum” “U of M grad student discovers Texas state dino isn’t really”
Louis L. Jacobs
Fort Worth Museum of Science and History
Abstract: A New Titanosauriform Sauropod
DinoData: Paluxysaurus jonesi