Comparative dental development and microstructure ofProconsulteeth from Rusinga Island, Kenya

• Published in: Journal of human evolution 1998-08, Vol.35 (2), p.163-209
• Main Authors: Beynon, A.D, Dean, M.C, Leakey, M.G, Reid, D.J, Walker, A
• Format: Article
• Language: English
• Subjects: dentine; enamel; enamel thickness; Miocene hominoids; Proconsul; Striae of Retzius
• ISSN: 0047-2484; 1095-8606
• DOI: 10.1006/jhev.1998.0230

Eighteen histological sections were prepared from eleven teeth attributed toProconsul heseloniand two molar teeth attributed toProconsul nyanzae. Measurements of spacings and counts of daily incremental markings in both enamel and dentine were possible in the majority of these tooth sections. Measurements of the spacings and angles to the enamel dentine junction (EDJ) of regular striae of Retzius and of equivalent markings in dentine were also made. In addition to these measurements, counts of perikymata were made on replicas of all otherProconsulteeth housed in the National Museum of Kenya, Nairobi, that preserved good perikymata on any aspect of their tooth surface. The sequence of crown formation inProconsuland the crown formation times of the enamel and dentine were estimated from these data. In addition, the rates of root extension were estimated using the formula derived for this purpose by Shellis (Archs. oral Biol.29, 697–705, 1984) and estimates of the total period of root formation subsequently made for premolar and molar teeth based on measurements of root length. A composite chart of dental development forP. heseloniis presented which suggests M3 root completion was between six and seven years of age. In generalProconsulmolar teeth have high stria angles to the EDJ, a high ratio of enamel formed with respect to dentine formed at the same time, median values of rates of enamel formation close to the EDJ in excess of 4μm per day and the occasional presence of “S-shaped” striae in the lateral enamel. There is no evidence to suggest thatProconsulfrom Rusinga Island, Kenya, had relatively thin enamel on molar or premolar teeth. When all of these data are considered in a comparative context,Proconsulemerges overall as hominoid-like in its enamel and dentine microstructure and as most similar toPongobut with some features shared withPanandHomo. Similar data for other Miocene primates will have considerable bearing on how these data are interpreted. These new data on dental microanatomy and on dental development inProconsulmake a further contribution to our understanding of the total morphological picture of this early Miocene primate.