Dr. Don Brinkman, Field Experience Program Coordinator, Royal Tyrrell Museum of Palaeontology
The 2002 Field Experience season in Dinosaur Park was an unqualified success. We collected excellent specimens that will fuel research projects for years to come. Our work involved collecting two major specimens, prospecting, and a joint project with the Museum of Australia, based in Sydney.
One of the excavations was a complete ceratopsian (horned) skeleton. In 2001, we started the excavation of a horned dinosaur, but we couldn't determine how much of it was there or its exact identity. We finally finished the excavation after six weeks into the 2002 season, recovering most of the skull as well as a nearly complete skeleton. Michael Ryan, a Ph.D. student specializing in horned dinosaurs, identified the specimen as a centrosaurine, but one that is different from any of the centrosaurines previously recovered from the park. The tentative identification is Achelousaurus, previously only known from Montana. The frill, which often separates from the front part of the skull, is the one major piece that is still not accounted for, but there is a chance it is buried in the hill.
We contained the specimen in three blocks or field jackets, the largest weighing an estimated two tons. Winches and over 300 metres of cable were used to pull the blocks from the quarry.
Associated remains of a long-necked plesiosaur found by a 2001 Field Experience participant gave us the chance to learn more about this rare and enigmatic reptile. A number of disassociated vertebrae and flipper elements were picked up on the surface. We don't know whether it's a freshwater species or the remains of a marine plesiosaur that spending some time in the rivers during the early stages of growth. Given the potential significance of this material, a quarry was undertaken and additional elements were recovered, although not sufficient to identify the taxon. The remains of a second specimen, also a long-necked plesiosaur, were found in the area, including cervical (neck) vertebrae, ribs, and gastralia. Among the material were very small centra, the smallest being approximately one cm in width. Although we don't have the answer yet, we think that these remains are from a different kind of plesiosaur from the one found in the overlying marine Bearpaw Formation.
In 2001, a series of articulated caudal vertebrae were found in the restricted area of the park, just east of the public loop road. The specimen appeared promising and in danger of rapid deterioration from erosion, but it proved to be only a partial skeleton including a partially disarticulated tail and hind limb - posing a puzzling taphonomic question - where did the front part of the body go?
Prospecting for new specimens is always a big part of our work in the park. We continued prospecting for new specimens, but this year's approach focused on a particular stratigraphic interval rather than a geographic area. The interval was the Lethbridge Coal Zone, a ten-metre thick sequence at the top of the Dinosaur Park Formation that is transitional between the lower fluvial beds and the marine Bearpaw Formation above. In 2001, we recognized that turtle elements often occur at the base of a marine interval in this transitional zone, along with marine taxa such as the fish Enchodus, ratfish, and sharks. One of the most significant turtle elements recovered is an upper jaw, which shows that this is different, and more advanced, than any of the other marine turtles found in Alberta.
Prospectors located a skull of the hadrosaurine Prosaurolophus. The tip of the snout and the cheekbones on the upper side are missing, allowing the braincase to be seen in lateral view. We also located two new hadrosaur skeletons. One consists of a series of seven articulated ribs and part of the vertebral column is visible and there is evidence of a skull. The second specimen shows a skull with the neck going into the hill. The skull and neck are filled in by ironstone, giving the appearance of three-dimensional preservation of the body. This specimen will be worked on this summer.
The last two weeks of the Field Experience Program in Dinosaur Provincial Park were dedicated to a joint project with the National Museum of Australia in Sydney. We will continue this collaborative work this summer. One of the goals of this will be a study of the paleoecology of the park. Another will be excavating sections of a ceratopsian bone bed for an exhibit that shows the bones in their original position.
