A comparative study of tooth root morphology in the great apes, modern man and early hominids
This thesis sets out to document and analyse some aspects of the metric and morphological variation of tooth roots within the Hominoidea. Samples of the extant species Gorilla gorilla, Pan troglodytes, Pongo pygmaeus and Homo sapiens formed the basis of this study, but fossil hominid specimens from the East African Plio/Pleistocene sites of Koobi Fora, Laetoli, Olduvai and Peninj were also included. The maximum of 182 root, crown and jaw measurements were taken for each specimen included in the comparative samples and included information for all permenent teeth except the maxillary canine. Premolar root number and form were also recorded for each specimen. The corresponding measurements and observations for the mandibular dentition were made, where possible, on the fossil hominid specimens. The metrical description of tooth roots in the pongids and modern man was accomplished by computing basic descriptive statistics for each measurement and for indices derived from the measurements. These statistical summaries formed the basis of an assessment of root size in the comparative samples. The pattern of sexual dimorphism in root dimensions is presented for each comparative sample, and assessment is also made of the contribution of sexual dimorphism to the variation recorded for root dimensions in the pooled-sex samples. Correlation analysis was used for a preliminary assessment of any interrelationship between root height and other dimensions. In the pongid and modern human samples, root number and form were recorded for both maxillary and mandibular premolars but in the fossil hominid sample this was possible only for the latter teeth. The assessment of the root and crown dimensions in the fossil hominid sample was conducted by grouping the fossil hominid specimens according to their mandibular premolar root morphology and then examining the dimensions in these fossil hominid groups.