Dental development and age at death of a Middle Paleolithic juvenile hominin from Obi-Rakhmat Grotto, Uzbekistan

Abstract

Studies of dental development have reported conflicting results regarding whether Neanderthal growth and development was similar to that of modern humans. The discovery of a partial permanent maxillary juvenile dentition (OR-1) from the Obi-Rakhmat Grotto, Uzbekistan, provides the opportunity to assess dental development and age at death in a Paleolithic hominin with strong Neanderthal similarities using incremental dental features. Long-period lines on tooth crowns (perikymata) and roots (periradicular bands) were quantified, and crown formation, root development, and age at death were estimated. An anomalous upper molar was determined to be a left M2 with a rare developmental condition (gemination). Perikymata numbers for OR-1 were similar to modern southern African population means, but were less than modern northern European and Neanderthal means. Root extension rates were estimated to be similar to (or slightly higher than) modern human values, although few modern comparative data are available. Assuming the long-period line periodicity of this individual fell within a Neanderthal distribution (6–9 days), the maximum age at death of OR-1 is estimated at 8.1 years, but is more likely to have been 6.7–7.4 years (7 or 8 day periodicity). Modern European human developmental standards would suggest an age at death of approximately 8–9 years. These results are consistent with other studies suggesting that Neanderthal dental development overlaps with the low end of modern human populations, and demonstrates a greater range of variation in Middle Paleolithic hominins than previously reported. It is clear that perikymata number alone does not distinguish these taxa; data on long-period line periodicity and molar eruption would yield additional insight into Neanderthal life history.