Dinosaur Name:   Pleurocoelus
Pronunciation:   (PLOOR-uh-SEEL-us)
Name Meaning:   Hollow side
When it lived:   115 million years ago, Early Cretaceous Period
Location of Dig:   Twin Mountains Formation on Jones Ranch in
Hood County

   The biggest dinosaur project ever untaken in Central Texas began in 1982 and is still underway. It started when some University of Texas students and their professor, Dr. Wann Langston, found bones on a Hood County ranch belonging to Bill and Decie Jones.

   This group worked to excavate the bones, which has proven to be no small task. Some of the bones are in a mostly clay-rich, sandy sediment, but many are encased in hard sandstone concretions. Over a decade, this group successfully retrieved about 20 bones, but the excavation was too much for them to complete.

   In November 1993 after completing the Doss Ranch excavation, the Southern Methodist University and Fort Worth Museum of Science and History collaborative team felt prepared for this sort of challenge. Jim Diffily, Museum curator, along with his SMU colleagues Louis Jacobs, Ph.D., and Dale Winkler, Ph.D., approached Dr. Langston, requesting permission to take over the dig. With him in agreement, the men then got permission from the landowners, and the team has been working that site ever since.

   The quarry itself is cut out of a cedar-covered hillside. Since 1993, heavy equipment has been used on four occasions to enlarge it, and the manpower requirements have been even greater.

   Several times a year, as many as 25 people gather at the quarry to work for seven to ten days. Each June, a number of school teachers aid in the effort, go to SMU, and visit the Fort Worth Museum of Science and History’s dinosaur exhibit as participants in the Museum’s Lone Star Dinosaurs Field Institutes.

   Digging in the bone-bearing layer is done by hand using standard tools: ice picks, trowels, and brushes.

   Sometimes, workers spend hours with a hammer and chisel separating the large sandstone, bone-bearing concretions into manageable sizes.

   A gas-powered diamond saw has proven very useful in dividing some blocks. As a series of small cuts are made, the sandstone is chipped away.

   The effort is paying off. Not only can digging be a very social occasion with many good conversations, the work has also been productive. Since taking over the dig, parts of four large, plant-eating sauropods have been excavated. Collection points are being mapped carefully, and data is collected in notebook after notebook.

   The bones, which were dark when they were first uncovered, have lightened as they have dried out. Because they had not been mineralized, they were quite soft and fragile. To stabilize them, a plastic resin dissolved in acetone has been applied to each one.

   Enough bone has now been collected to assemble and study, although only half of the bones found so far have been chipped out of the incredibly hard rock matrix. Since this type of dinosaur is so huge – 70 feet long, 12 foot high at the hips, and weighing 20 tons – its bones come out of the ground in big blocks, the largest weighing 22,000 pounds. As the bones are extracted, they will be added to the skeleton.

   After years of study, the team believes that this four-legged creature is a new species of sauropod from the Early Cretaceous Period. An SMU graduate student has written a species description paper, which was submitted for peer review and awaits publication. The Texas legislature adopted the animal, now known as Pleurocoelus, as the official state dinosaur. Considering that it is the largest dinosaur in Texas and that everything is bigger in Texas, this seems quite fitting.

   And yet the work continues. After all, excavating a Texas-sized dinosaur is a Texas-sized job.

Photo Album:
View all 36 photos of the Jones Ranch excavation at a larger scale.


 


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