Department of Anthropology, Texas A&M University
Saturday All day, Park Concourse
Supernumerary teeth have been reported in a wide range of fossil primate taxa including Eocene adapoids, Plio-Pleistocene hominins, and other non-human hominids. In modern humans, a review of the literature shows that polydontia is less common than agenesis, more frequent in males than in females, and generally occurs at frequencies of less than 5%. In extant non-human hominids, percent incidence of supernumerary teeth varies, with the overall pattern usually documented as Pongo > Gorilla > Pan. Within the genus Pongo, percent incidence reported generally ranges between 6 to 20%. In a published study on hybridization in a captive baboon population comprised of two closely related species, a high incidence (44%) of supernumerary molars was reported in F1 hybrids males. Along with similar results documented in a study on hybridization between gorillas, these studies suggest that high frequencies of additional molars within a population may indicate hybridization. For the present study, a survey of specimens held at the Cleveland Museum of Natural History, the American Museum of Natural History, and the Smithsonian National Museum of Natural History, revealed the pattern of incidence of supernumerary molars in non-human hominid skulls examined to be 7.1, 4.7 and 1.2% for Pongo, Gorilla, and Pan, respectively. The high incidence of supernumerary molars as evidence for possible hybridization in Pongo is considered here, along with divergence date estimates, population genetics and biogeography. Finally, a method to test if the high incidence of supernumerary molars in Pongo is associated with hybrid individuals is proposed.