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The tooth of the matter

Juliet Brophy, PhD, studies teeth to help identify early human ancestors


ast fall, more than 1,200 hominid fossils were discovered and excavated in and around a cave system called Rising Star in northeast South Africa. The quantity and preservation level of

the findings garnered international attention, and the world is waiting to find out what exactly Rising Star contains. Paleoanthropologist Juliet Brophy, PhD, a lecturer in Loyola’s Department of Anthro- pology, is one of the scientists who will help answer that question. Brophy is now on site at Rising Star, analyzing

fossil teeth and comparing them to data sets from other sites. By photographing the teeth, digitizing their images, and, in the simplest terms, trying to match the shapes to others in her collection, she may be able to identify the species of hominids— our early human ancestors—whose remains have been in those caves for millions of years. The first teeth Brophy analyzed were those of

bovids, which are in the same family as cows. Although paleoanthropology is an interpretive

science, Brophy was uncomfortable with the level of subjectivity she saw in the field. “I would say, how do you know it’s X instead

of Y?” Brophy says. “If you have a large X, it might look like a small Y. How did you know how to divide those up? Two people can identify the same fossil differently. Or a person can look at a fossil and identify it, only to look at it again 10 years later and change their mind.” Brophy landed on tooth shape analysis as a way to combat interobserver error and make

Juliet Brophy, PhD, of the anthropology department, analyzes the shape of tooth fossils to identify ancient species. She is currently at the Rising Star site in South Africa.

identification less subjective. “We rely upon these animals [bovids] really heav-

ily to determine all these hypotheses about extinc- tion events and behavior and adaptations,” Brophy says. “If there’s subjectivity in their identification, and we’re misidentifying these bovids, we’ll have false results and make wrong hypotheses based on them.” With a more objective way of identifying bovid

species by tooth shape, she was able to reconstruct the environment of one of our early human ances- tors, throwing doubt on some standing hypotheses

about what caused that species to go extinct. Since she had been so successful with the bovid

teeth, Brophy applied the method to analyze hominid teeth at a site called Malapa, also in South Africa, in 2010. “So we compared the tooth shape of the indi-

viduals we identified at Malapa to other species found in the same area in order to aid in their iden- tification,” Brophy says. “The individuals turned out to be a transitional species between early human ancestors and our genus, Homo.” Brophy’s data sets from Malapa are among those


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