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Title: Quantifying linear enamel hypoplasia in Virunga Mountain gorillas and other great apes
Abstract Objective

Linear enamel hypoplasia (LEH) is a condition marked by localized reductions in enamel thickness, resulting from growth disruptions during dental development. We use quantitative criteria to characterize the depth of LEH defects and “normal” perikymata in great apes. We test the hypothesis that mountain gorillas have shallow defects compared to other taxa, which may have led to their underestimation in previous studies.

Materials and Methods

Previous attempts to characterize LEH morphology quantitatively have been limited in sample size and scope. We generated digital elevation models using optical profilometry (Sensofar PLu Neox) and extracted 2D coordinates using ImageJ to quantify depths in canines from three great ape genera (N = 75 perikymata; 255 defects).

Results

All defect depths fall outside the distribution of perikymata depths. Mountain gorilla defects are significantly shallower than those of other great ape taxa examined, including western lowland gorillas. Females have significantly deeper defects than males in all taxa. The deepest defect belongs to a wild‐captured zoo gorilla. Virunga mountain gorilla specimens collected by Dian Fossey exhibit deeper defects than those collected recently.

Discussion

Shallow defect morphology in mountain gorillas may have led to an underestimation of LEH prevalence in past studies. Defect depth is used as a proxy for insult severity, but depth might be influenced by inter‐ and intra‐specific variation in enamel growth. Future studies should test whether severe insults are associated with deeper defects, as might be the case with Haloko, a wild‐captured gorilla. Ongoing histologic studies incorporating associated behavioral records will test possible factors that underlie differences in defect morphology.

 
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Award ID(s):
0852866 0964944 1520221
NSF-PAR ID:
10053619
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
American Journal of Physical Anthropology
Volume:
166
Issue:
2
ISSN:
0002-9483
Page Range / eLocation ID:
p. 337-352
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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