Electron spin resonance (ESR) dating of the origin of modern man

Patterning of geographic variation in Middle Pleistocene Homo frontal bone morphology

A quantitative assessment of the frontal bone morphology of a sample of Middle Pleistocene hominins was undertaken in order to address questions regarding their population structure and evolutionary history. Outline tracings of the frontal bones of forty-seven fossil crania were obtained, and size-standardized measurements were then computed using an Elliptical Fourier analysis of these tracings. Principal component scores of the Fourier harmonic amplitudes were derived and served as a quantitative representation of the morphology of the frontal bone. Morphological, geographical, and temporal distance matrices were then constructed between each pair of fossils. A partial Mantel matrix correlation test was performed between morphological and geographical distance matrices, controlling for temporal distance, in order to determine if the pattern of geographical differentiation in features of the frontal bone of mid-Pleistocene Homo followed that of an isolation-by-distance model of population structure. The results of the partial Mantel tests indicate that the overall patterning of differentiation in the features of the frontal bone cannot best be explained by a population structure shaped by isolation-by-distance. Additionally, various aspects of the frontal bone quantified here follow different patterns of geographical differentiation, suggesting that a mosaic pattern of evolution holds true for characters within one cranial region and not just for those between regions.

Latest Homo erectus of Java: potential contemporaneity with Homo sapiens in southeast Asia

Hominid fossils from Ngandong and Sambungmacan, Central Java, are considered the most morphologically advanced representatives of Homo erectus. Electron spin resonance (ESR) and mass spectrometric U-series dating of fossil bovid teeth collected from the hominid-bearing levels at these sites gave mean ages of 27 +/- 2 to 53.3 +/- 4 thousand years ago; the range in ages reflects uncertainties in uranium migration histories. These ages are 20,000 to 400,000 years younger than previous age estimates for these hominids and indicate that H. erectus may have survived on Java at least 250,000 years longer than on the Asian mainland, and perhaps 1 million years longer than in Africa. The new ages raise the possibility that H. erectus overlapped in time with anatomically modern humans (H. sapiens) in Southeast Asia.

Dating and context of three middle stone age sites with bone points in the Upper Semliki Valley, Zaire

The extent to which the earliest anatomically modern humans in Africa exhibited behavioral and cognitive traits typical of Homo sapiens sapiens is controversial. In eastern Zaire, archaeological sites with bone points have yielded dates older than 89(-15)+22 thousand years ago by several techniques. These include electron spin resonance, thermoluminescence, optically stimulated luminescence, uranium series, and amino acid racemization. Faunal and stratigraphic data are consistent with this age.