The Museum’s fossil preparation facility, FossiLab, recently received a shipment of dinosaur fossils from northern Zimbabwe. They were collected last year by an international team of scientists, including NMNH Dinosaur Curator Matt Carrano.
The fossils, still largely encased in rock, are of two types of dinosaur. One, a small, primitive meat eater closely related to Coelophysis, was a member of the dinosaur group that eventually gave rise to huge predators like T. rex. These fossils were found in a “bone bed,” a place where the fossil remains of many individuals are mixed together. Coelophysis fossils have been found in other bone beds, most famously at Ghost Ranch in New Mexico, and the new discovery may help scientists answer questions such as whether Coelophysis and related species lived in groups, and what events led to the death and burial of so many animals at once. The other Zimbabwean dinosaur is a prosauropod, a medium-sized plant eater that had a large claw on its thumb, a long neck, and leaf-shaped teeth for chopping plant matter. They seem to have been quite common at a time when the local environment was desert, and researchers wonder why.
The scientists discovered the fossils in a river canyon. During the rainy season, water courses through the canyon eroding its rock walls and uncovering fossils. Then, when the rains stop, the riverbed dries up and becomes a convenient path for scientists prospecting for newly exposed fossils – and for lions and elephants traveling through the bush.
Paleontologists are friendly, as a rule, but prospecting can be solitary work. Team members often spread out to cover as much territory as possible, and as they walk slowly along searching for fossils, they sometimes become oblivious to everything around them. Obviously, this is not the smartest behavior when large, possibly dangerous animals are nearby, so the team hired a local wildlife guide to keep them out of trouble. He coached them on what not to do when charged by lions (run), or elephants (stand still) and kept them bunched together in the relative safety of a “herd” as they prospected in the canyon.
The scientists found the tracks of several big cats as they worked in the riverbed, but, to their relief, they came face to face with only one group of predators -- dinosaurs, all safely fossilized.
Abby Telfer, FossiLab Manager, Paleobiology Department
Image captions and credits (top to bottom): At the Museum, a plaster and burlap field jacket holds a jumble of dinosaur fossils from the bone bed, including a jaw fragment with teeth (center). Photo by A. Telfer; Removing fossils from the canyon wall in Zimbabwe. Photo by M. Carrano; Leopard tracks in the dry riverbed. Photo by M. Carrano.