In 2003, our field teams working in the Triassic age sediments within the Grand Staircase–Escalante National Monument in Utah discovered the almost complete, articulated skeleton of a Poposaurus. Poposaurus is a little known carnivore that, while it resembles a small theropod dinosaur, is actually more closely related to crocodilians. For the past year we have been carefully removing the rock (the matrix) that has entombed this important skeleton for over 240 million years.
Assistant Preparator Vicki Fitzgerald and Curator Jacques Gauthier open one of the 6 field jackets of the Poposaurus collected in 2003. Large specimens were encased in plaster and burlap to protect them during their long trip from Utah back to New Haven. In the Lab the jackets are carefully opened to reveal the specimen inside.
Vicki carefully cleans and glues together all the tiny fragments of bone that had weathered out from our Poposaurus fossils (fossils can only be found when they weather out of rock). Paleontologists walk every hill and gully looking for tiny bits of bone that indicate that there could be a whole skeleton just underneath the surface.
The jackets contain most of the bones from the rear part of the skeleton. The open jackets, which have been partially prepared, are laid our in the picture to show how the specimen lay in the rock. The outline drawing shows how the bones were preserved.