Evo-devo models of tooth development and the origin of hominoid molar diversity.
The detailed anatomical features that characterize fossil hominin molars figure prominently in the reconstruction of their taxonomy, phylogeny, and paleobiology. Despite the prominence of molar form in human origins research, the underlying developmental mechanisms generating the diversity of tooth crown features remain poorly understood. A model of tooth morphogenesis-the patterning cascade model (PCM)-provides a developmental framework to explore how and why the varying molar morphologies arose throughout human evolution. We generated virtual maps of the inner enamel epithelium-an indelibly preserved record of enamel knot arrangement-in 17 living and fossil hominoid species to investigate whether the PCM explains the expression of all major accessory cusps. We found that most of the variation and evolutionary changes in hominoid molar morphology followed the general developmental rule shared by all mammals, outlined by the PCM. Our results have implications for the accurate interpretation of molar crown configuration in hominoid systematics.
Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA. Center for the Study of Human Origins, Department of Anthropology, New York University, New York, NY 10003, USA. Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany. Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA. Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany. Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany. School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NR, UK.
