title: Evolutionary and morphological significance of the deflecting wrinkle in the lower molars of the Hominoidea.
abstract: The deflecting wrinkle is a well-known character state of the lower m2 and M1 of the human dentition, but there is little information regarding its presence in great apes. The deflecting wrinkle is more frequent on M2-3 in all extant pongid genera studied in this paper except Pan paniscus, in which M1 has the highest frequency (16.0%) and in which this wrinkle is absent on M3. In Gorilla, it is absent on M1, with only a low incidence on M2-3. Its greatest frequency in Pongo is always on M2 (20.2%), which is the greatest expression of the trait in the great apes. We interpret the presence of the deflecting wrinkle as an incidental effect and suggest that it represents a plesiomorphic character state in the Hominoidea.
mesh_terms: D000818:Animals; D000885:Anthropology, Physical; D005075:Biological Evolution; D005260:Female; D005580:Fossils; D000882:Haplorhini / Q000033:anatomy & histology* / Q000235:genetics; D006801:Humans; D008297:Male; D008963:Molar / Q000033:anatomy & histology*; D011110:Polymorphism, Genetic