Papers by Antonis Bartsiokas
Journal of Human Evolution, Apr 1, 2008
The Anatomical record, 2002
The microstructure of a hominid cranial vault has not previously been studied to determine its ti... more The microstructure of a hominid cranial vault has not previously been studied to determine its tissue histology, and differences in comparison with that of modern humans. We selected the parietals of Omo-Kibish 1, regarded as one of the oldest (about 130,000 years old) anatomically modern humans, and Omo 1 (Howell), which is a very recent human (about 2,000 years old)-both from the same area of Ethiopia. A combination of macrophotography, polarizing microscopy in the incident and transmission illumination mode, and confocal laser scanning microscopy (CLSM) was employed to examine thin sections, as well as polished and unpolished block faces of unembedded bone fragments, to minimize specimen destruction as much as possible. The methods enabled remarkably detailed information on bone microstructure and remodeling to be gleaned from tiny fragments of bone. The best method for examining fossilized human bones was shown to be that of incident light microscopy, which was the least destruc...
Proceedings of the Royal Society B: Biological Sciences, 1993
Doubts about the attribution of the Trinil femur to Homo erectus on anatomical grounds have a lon... more Doubts about the attribution of the Trinil femur to Homo erectus on anatomical grounds have a long history. Here, for the first time, published stratigraphic information and chemical evidence based on the Ca/P ratios confirm that the anatomical doubts are justified. The Trinil femur apparently belongs to a more recent stratum above the 'fossil layer' (Hauptknochenschicht, HK) in which the Trinil calotte was found. It is concluded that the Trinil Femur I belongs to Homo sapiens, whereas the Trinil Femora II-V and the calotte belong to H. erectus. The chemical evidence derives from the use of electron probe energy dispersive X-ray microanalysis (EDXA), a technique that can be virtually non-destructive and therefore may be used on scarce fossil evidence.
Journal of Human Evolution, 1993
Journal of Human Evolution, 2008
Journal of Human Evolution, 2012
While it is generally accepted that modern humans evolved in Africa, the specific physical eviden... more While it is generally accepted that modern humans evolved in Africa, the specific physical evidence for that origin remains disputed. The modern-looking Omo 1 skeleton, discovered in the Kibish region of Ethiopia in 1967, was controversially dated at ~130 ka (thousands of years ago) by U-series dating on associated Mollusca, and it was not until 2005 that Ar-Ar dating on associated feldspar crystals in pumice clasts provided evidence for an even older age of ~195 ka. However, questions continue to be raised about the age and stratigraphic position of this crucial fossil specimen. Here we present direct U-series determinations on the Omo 1 cranium. In spite of significant methodological complications, which are discussed in detail, the results indicate that the human remains do not belong to a later intrusive burial and are the earliest representative of anatomically modern humans. Given the more archaic morphology shown by the apparently contemporaneous Omo 2 calvaria, we suggest that direct U-series dating is applied to this fossil as well, to confirm its age in relation to Omo 1.
Laser ablation U-series dating results on human and faunal bone fragments from Wajak, Indonesia, ... more Laser ablation U-series dating results on human and faunal bone fragments from Wajak, Indonesia, indicate a minimum age of between 37.4 and 28.5 ka (thousands of years ago) for the whole assemblage. These are significantly older than previously published radiocarbon estimates on bone carbonate, which suggested a Holocene age for a human bone fragment and a late Pleistocene age for a faunal bone. The analysis of the organic components in the faunal material show severe degradation and a positive d 13 C ratio indicate a high degree of secondary carbonatisation. This may explain why the thermal release method used for the original age assessments yielded such young ages. While the older U-series ages are not in contradiction with the morphology of the Wajak human fossils or Javanese biostratigraphy, they will require a reassessment of the evolutionary relationships of modern human remains in Southeast Asia and Oceania. It can be expected that systematic direct dating of human fossils from this area will lead to further revisions of our understanding of modern human evolution.
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Papers by Antonis Bartsiokas