Anne Dangerfield and Dr. Brooks Britt, Geology

My original project focused on the comparison of postcranial bones of two species of Allosaurus with the goal of differentiating the species based on limb robustness. A detailed study of 78 bones showed that there were at least 13 individuals of Allosaurus in the Dry Mesa quarry that belong to Allosaurus jimmadseni. Measurements of the A. jimmadseni specimens were compared with those of A. fragilis from two other institutions. There were no significant differences except for the robustness of the femur bone, which is less robust in A. jimmadseni than A. fragilis. My conclusion is that although the skulls of these two species differ substantially, the postcranial skeletons are virtually indistinguishable on ratios alone. I will continue to work on this paper with the goal of presenting our results at a national meeting of the Society of Vertebrate Paleontology.

As part of the Allosaurus project my mentor assigned me the task of collecting statistics on the frequency of occurrence of pits on all of the theropod bones that I studied. This was soon expanded to include other taxa in a number of collections in Utah, Montana, and Minnesota. The grant money was used to cover part of my travel expenses. Although pits on dinosaur bone from the Jurassic age Morrison Formation have been noted by paleontologists for a number of years, few papers on them have been and all attributed the marks to the work of dermestid beetles. A literature search revealed that termites consume bone and leave traces similar to those seen on Morrison Fm. bone. This data inspired a new course of action, the investigation of a hypothesis that termites, and not beetles, are responsible for these traces.

Research began by looking into published works on termite and other insect traces found on bone – both fossil and modern. Surprisingly, we found that only three modern insects are known to consume bone, namely tineid moths, dermestid beetles, and termites. Since markings left by tineid moths were very different from those seen on the Morrison bones, distinguishing between dermestid beetle traces and termite traces became the main focus.

Most of my contribution came during data collection. In order to know the extent of dinosaur bones eaten by termites, many different Morrison quarries needed to be examined for pits. Among the different features looked for were the abundance of pitting, the location, the size variation, the style, and the element they were located on, i.e. femur, tibia, scapula, etc. The eight quarries present in BYU’s collection underwent the most scrutinized investigation. Methods included a mechanics drop light shone at an oblique angle to the surface on the bone. This brought out all of the surface topography and allowed even the smallest pits to be seen. All of the information collected was stored in the museum data base and the best looking specimens were set aside to be photographed for publication.
The examination of the BYU collection showed pits range in size from <1-20mm, were very shallow, that bones were generally pitted on one side only, patterns of pitting were various sized clusters or lineations, and limb and pelvic elements were most heavily pitted. Quarry maps showed the side of bones most heavily pitted was face down on the ground when excavated. This data fit with the termite hypothesis and argued against the view that dermestid beetles were responsible for the destruction of Jurassic dinosaur carcasses. The literature review showed a large range in size for termite traces and a fixed size for dermestids, which fit with the

Once BYU quarries were studied it was time to look at collections from other Morrison quarries to see if the same features were observed there. I traveled to a number of different Museums and universities gathering addition data to see if it would support or refute our hypothesis. Among placed visited were the University of Utah, the College of Eastern Utah, the Museum of the Rockies in Bozeman, Montana, and the Science Museum of Minnesota and Minnesota State University in Minneapolis. Methods and procedures of collecting data were the same as those used at BYU. Pictures of the best samples were also taken and included in the figures for publication. Features seen at these places were very similar to those from the BYU quarries. Size range and patterns were consistent but in many cases bones were pitted even more heavily than those from BYU’s quarries. In this way, some of the data collected was even more supportive of the termite hypothesis. On one particular sample from Museum of the Rockies, pieces of what is suspected to be part of a termite nest was found on top of the bone covering underlying pits.

There could still be research done on this topic, particularly looking in to the suspected termite nest to see if that is indeed what it is and if there are any other traces of it present in the quarry. Another aspect that could be looked into is the climatic and environmental conditions that termites thrive in, which would give more insight into what the conditions were like during the Jurassic Period.

The experience I have gained from doing this research has been invaluable. In addition to being an author on the paper submitted to The Journal of Paleontology, I was also able to present my findings at two national meetings of the Geological Society of America, in 2004 and 2005. While traveling I met a number of different specialists in the paleontology field and made many good contacts. I also got to see what other opportunities are open for exploration. The biggest gain from doing this research however, was just that; doing the research. It has given me an advantage over many other undergraduates who decide to continue their education to the Master’s or Ph.D. level. Effective research leads to effective scientists, and I know this experience will increase the caliber of my future career. I truly appreciate the generosity of donors and the ORCA grant that made this research possible.