October 1, 2007

A Case of Mistaken Dino-Identity

For decades paleontologists have been calling the massive dinosaur whose tracks and bones litter the central Texas Jones Ranch Pleurocoelus. But SMU alumnus Peter Rose has determined it was a different dinosaur altogether – a previously unrecognized genus and species he has named Paluxysaurus jonesi, after W.W. Jones, the owner of the land on which the fossils were found.

Rose’s discovery was recently published in Palaeontologia Electronica, an online journal of the Society of Vertebrate Paleontology. His master’s degree study of an SMU collection of large, sauropod bones from the banks of the Paluxy River near Glen Rose disputes the traditional notion that the central Texas bones are of the same as Pleurocoelus bones first found in Maryland in the late 1800s.

“Historically, a lot of sauropod remains from Texas of similar age were associated with that animal – but were never really demonstrated to be,” Rose said.

Sauropods were the largest of the known land animals in the Jurassic and Cretaceous periods, periods that extended from about 190 million years to about 66 million years ago. Including the classroom-familiar Apatosaurus and Brachiosaurus, sauropods were plant-eaters with small heads, long necks and tails and five-toed limbs. The fossilized footprints they left behind are big enough for a toddler to use as a wading pool.

The site about 60 miles southwest of Fort Worth where Paluxysaurus jonesi has been excavated was discovered in the 1950s. SMU professor of geological sciences Louis Jacobs, who was Rose’s mentor, said that nobody before Rose had made an adequate study of the bones found there. SMU worked with the Fort Worth Museum of Science and History to excavate the fossils. Then it took more than a decade in the laboratory to free the bones from the hard rock that encased them.

“I went back and observed the material from Jones Ranch that has been at SMU for a number of years and compared it to other sauropod material in North America, and globally as well,” Rose said. “Based on those comparisons of the anatomy, from the skeletal material, I determined it was distinct from anything previously described and named.”

Rose, 28, received his master’s degree in geological sciences from SMU in 2004. He is currently pursuing a Ph.D in paleontology at the University of Minnesota.

Rose can be reached at 612-849-0430 or by e-mail at



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