Morphology of Deciduous Canines in African Apes

Abstract

The aim of this study was to determine the morphology and sexual dimorphism of deciduous canines in African great apes. The morphology of the deciduous canines of the chimpanzee and the gorilla was similar in both the male and the female. The occlusal view of the chimpanzee showed an ellipsoid shape in the maxilla and a more distorted quadrilateral shape in the mandible. The lingual view showed a pyramidal triangle in the maxilla and a distorted square in the mandible. Compared to chimpanzees, gorillas had a larger maxillary labiolingual diameter, a more elliptical shape, a higher crown height and more mesial grooves. The basal tubercles, spinous processes and distal accessory ridges observed in human primary canines were not observed in chimpanzees and gorillas. No significant sex differences were found for maxillary and mandibular primary canines in chimpanzees. However, in the maxilla, there were significant sex differences in gorillas for all variables except mesiodistal diameter. Compared to humans, chimpanzees were significantly larger for all variables except maxillary labiolingual diameter. On the other hand, the crown index was significantly larger in humans and the occlusal view was more rounded. The deciduous canines of chimpanzees and gorillas were similar in morphology to the permanent canines of females of both species. However, they differed significantly from the permanent canines of males.