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Disruptions in Dental Growth in the Bonobo, Pan paniscus: Implications 
for Conservation

Advisors: Zeynep Benderlioglu and Debbie-Guatelli-Steinberg
Presenters: Erika Williams, Regan Hitt, Johnathan Hubbard, and Samantha Witchey

Erika Williams, Regan Hitt, Johnathan Hubbard, and Samantha Witchey in front of research poster at Denman

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.