Growth processes in teeth distinguish modern humans from Homo erectus and earlier hominins.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Dean, C; Leakey, M G; Reid, D; Schrenk, F; Schwartz, G T; Stringer, C; Walker, A
Year of Publication: 2001
Journal: Nature
Volume: 414
Issue: 6864
Pagination: 628-31
Date Published: 2001 Dec 6
Publication Language: eng
ISSN: 0028-0836
Keywords: Adult, Animals, Biological Evolution, Dental Enamel, Dentition, Fossils, Hominidae, Humans, Species Specificity, Tooth

A modern human-like sequence of dental development, as a proxy for the pace of life history, is regarded as one of the diagnostic hallmarks of our own genus Homo. Brain size, age at first reproduction, lifespan and other life-history traits correlate tightly with dental development. Here we report differences in enamel growth that show the earliest fossils attributed to Homo do not resemble modern humans in their development. We used daily incremental markings in enamel to calculate rates of enamel formation in 13 fossil hominins and identified differences in this key determinant of tooth formation time. Neither australopiths nor fossils currently attributed to early Homo shared the slow trajectory of enamel growth typical of modern humans; rather, both resembled modern and fossil African apes. We then reconstructed tooth formation times in australopiths, in the approximately 1.5-Myr-old Homo erectus skeleton from Nariokotome, Kenya, and in another Homo erectus specimen, Sangiran S7-37 from Java. These times were shorter than those in modern humans. It therefore seems likely that truly modern dental development emerged relatively late in human evolution.

DOI: 10.1038/414628a
Alternate Journal: Nature
Related MOCA Topics: