Neanderthals in the news

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May 18, 2011

Neanderthals were back in the news last week. But then, Neanderthals are seldom out of the news and have not ceased to fascinate us since they were discovered and named about 150 years ago. The most recent news making events are two: a challenge to the dates that have been assigned to Neanderthal remains closest to the time of their extinction; and a claim Neanderthals occupied a site in the Siberian far North, at much higher latitudes than previously thought possible.

First, let’s talk about the dating of Homo neanderthalensis remains. Many researchers believe H. neanderthalensis arose as a separate species in Eurasia around 200,000 years ago and occupied a range stretching from Spain in the West to Central Asia in the East. They were a cold adapted people and endured severe climate fluctuations, including several periods of increased glaciation throughout their existence. Sometime between 50,000 and 40,000 years ago, anatomically modern human populations, Homo sapiens, entered the Levant from Africa and began branching East and West possibly encountering Neanderthal populations. Neanderthal remains have been found at many sites within the range described above and the remains closest in time to the present day were found in Spain near Gibraltar and dated to about 28,000 years ago.

Neanderthal extinction came about because the populations of H. sapiens moving in from Africa were more successful in the competition for resources, it is believed. There is no evidence of deadly conflict between the two species.

A radioactive isotope, carbon-14, and part of the carbon molecule, found in unfossilized human and animal bone and charcoal, has been used to date Neamderthal remains and it was this carbon-14 dating method that established the date for Neanderthal extinction - 28,000 years ago - as well as the dates assigned to the various Neanderthal sites found throughout Eurasia. Two researchers in a Science paper last week questioned these dates, arguing they had developed a more reliable means of establishing carbon-14 dates. They posit Neanderthal extinction occurring around 39,000 years ago and raise the possibility the period of contact between H. nenderthalensis and H. sapiens entering from Africa could have been as brief as a few hundred years and was no greater than 6000 years instead of the previously accepted 15/20,000 years.

The suggestion dating was based on less accurate methods with possibilities of contamination and that a more reliable method has been found met with some skepticism among scientists specializing in this area of study and we can expect continued discussion.

The article appeared in the Proceedings of theNational Academy of Sciences (PNAS) and here is the abstract of that article:

Revised age of late Neanderthal occupation and the end of the Middle Paleolithic in the northern Caucasus
"Advances in direct radiocarbon dating of Neanderthal and anatomically modern human (AMH) fossils and the development of archaeostratigraphic chronologies now allow refined regional models for Neanderthal–AMH coexistence. In addition, they allow us to explore the issue of late Neanderthal survival in regions of Western Eurasia located within early routes of AMH expansion such as the Caucasus. Here we report the direct radiocarbon (14C) dating of a late Neanderthal specimen from a Late Middle Paleolithic (LMP) layer in Mezmaiskaya Cave, northern Caucasus. Additionally, we provide a more accurate chronology for the timing of Neanderthal extinction in the region through a robust series of 16 ultrafiltered bone collagen radiocarbon dates from LMP layers and using Bayesian modeling to produce a boundary probability distribution function corresponding to the end of the LMP at Mezmaiskaya. The direct date of the fossil (39,700 ± 1,100 14C BP) is in good agreement with the probability distribution function, indicating at a high level of probability that Neanderthals did not survive at Mezmaiskaya Cave after 39 ka cal BP ("calendrical" age in kiloannum before present, based on IntCal09 calibration curve). This challenges previous claims for late Neanderthal survival in the northern Caucasus. We see striking and largely synchronous chronometric similarities between the Bayesian age modeling for the end of the LMP at Mezmaiskaya and chronometric data from Ortvale Klde for the end of the LMP in the southern Caucasus. Our results confirm the lack of reliably dated Neanderthal fossils younger than ?40 ka cal BP in any other region of Western Eurasia, including the Caucasus."

Additionally a thorough discussion can be found in the New York Times. See also Science.

In a related but separate article in Science, other scientists claim H. neanderthalensis occupation at a site called Byzovaya Cave in Siberia, at about 65 deg, north latitude and dated to about 32,ooo years ago. The interesting point here is that no Neanderthal remains have been found at this site, only stone tool artifacts said to be of the same Mousterian technology as that used by H. neanderthalensis. Other scientists are skeptical, stating it is unprecedented to attribute a site to a particular tax on when there are no anatomical remains, only artifacts.

Download the discussion in Science.

To learn more about Homo neanderthalensis in general, go to the timeline found on this website, The Human Lineage Through Time.