Advisors: Zeynep Benderlioglu and Debbie-Guatelli-Steinberg
Presenters: Erika Williams, Regan Hitt, Johnathan Hubbard, and Samantha Witchey
Stressors in the environment during critical periods of development leave enduring signs on anatomical characters. Linear Enamel Hypoplasias (LEHs), appearing as lines, grooves, or furrows in the enamel surface is one such sign in teeth. LEHs, in turn, have been used as a proxy for physiological stress due to variations in temperature, precipitation, and food availability. Our study examined the disrupted growth patterns and length of tooth formation in the bonobo, Pan paniscus. We took images of canine replicas of both male and female bonobos with a high resolution camera. We examined the distances of each LEH from an anatomical landmark, the cementoenamel junction (CEJ), to determine the length of tooth formation periods and disrupted growth patterns. We used the open source ImageJ software to calculate these distances and transfer data to perform statistical analyses. Our results show that the total LEH count was positively correlated with elapsed time in tooth formation. The frequency of LEH was higher in males compared to that of the females. Male tooth formation also took longer than females. Females had nearly uniform rates of tooth formation from cusp to CEJ. Males, in turn, had more sporadic rates, presumably indicating more vulnerability to physiological stress as evidenced by more LEH counts. These data are consistent with previous studies on other non-human primates. LEH expression can be a powerful tool in bioarcheology, as well as in human biology studies to assess physiological stress. Careful examination of dental structures with large samples can give us clues on timing and duration of stressors along with historical records on environmental changes and habitat conditions. This has important implications for conservation efforts, especially for great apes.