If the middle Pleistocene 40Ar/39Ar ages better reflect the age of the Solo River 20 meter terrace deposits and hominins, the site of Ngandong remains a relatively late source of H. erectus; however, these H. erectus would not be the contemporaries of Neandertals and modern humans, and their chronology would widen the gap between the last surviving H. erectus and the population from Flores – whose source population has been argued to be Indonesian H. erectus [47], [48]; although this point is contested, [49]. Instead, the Ngandong hominins would be contemporaries of the H. heidelbergensis from Atapuerca, Spain and elsewhere in Europe, and, possibly the archaic H. sapiens specimen from Bodo (Ethiopia), which might favor arguments that they are more closely affiliated with these taxa and differ from H. erectus [50], [51]. Such ages for Ngandong would suggest that a series of geographically relatively isolated lineages of hominins lived during the middle Pleistocene.

In light of these results we are faced with a conundrum of opposing, yet internally consistent, estimates from different dating systems. This raises two possible scenarios: the pumices may all be reworked from older deposits, such as the Pohjajar Formation, and do not reflect the age of the Solo River deposits or hominins; alternatively, the ESR, U-series, and γ spectrometric 230Th/234U age determinations on teeth and bones, although internally consistent, may not be dating the age of deposition but of some other events of more recent hydrological activity associated with U-mobilization

Our results raise several issues for the interpretation of the Ngandong site, the intercalibration of 40Ar/39Ar age estimates and other chronometers, and the evolution of H. erectus. On the basis of geomorphology, absence of clear indicators of time-transgression at the site (e.g., mixed deposits), and the reasonable consistency of the ESR and U-series results, which argue against reworking, we suggest that, whatever their age, the fauna and hominins are of similar geological age. In the absence of any reliable 40Ar/39Ar age estimates, some of us have previously favored this to be a late Pleistocene age [3], [4]. We continue to see no basis for dismissing the earlier open system ESR and U-series dates because they meet the scientific criteria for acceptability applied to these systems. That is, they are nonrandom and internally consistent with the stratigraphy of the sites.

It is the case that this age may not be that of deposition of the site, and we raise the possibility that these ages date some later geomorphologic or hydrologic event (other than the initial deposition of the sediments and hominins). Nonetheless, these age estimates certainly supply a minimum age for the site.

An ancestor of humans may have became extinct earlier than previously thought, throwing doubt on the theory of evolution

Spearthrower wrote:No retraction from the Associated Press, not even so much as an email response addressing the fact as to why they've published a complete falsification of a scientific study.