They may be yellowed and worn but these ancient teeth and jaw fragment have something very revealing to say about how modern humans conquered the globe.
The specimens, unearthed in Italy and the UK, have just been confirmed as the earliest known remains of Homo sapiens in Europe.
Careful dating suggests they are more than 41,000 years old, and perhaps as much as 45,000 years old in the case of the Italian "baby teeth".
The re-assessments have further importance because palaeoanthropologists can now put modern humans in the caves at the same time as the stone and bone tool technologies discovered there.
There has been some doubt over who created the so-called Aurignacian artefacts at Kents Cavern and the slightly older Uluzzian technologies at Grotta del Cavallo. It could have been Neanderthals, but there is now an obvious association in time with Homo sapiens.
From the NY Times:
They had in fact discovered the oldest known skeletal remains of anatomically modern humans in the whole of Europe, two international research teams reported Wednesday.
The scientists who made the discovery and others who study human origins say they expect the findings to reignite debate over the relative capabilities of the immigrant modern humans and the indigenous Neanderthals, their closest hominid relatives; the extent of their interactions; and perhaps the reasons behind the Neanderthal extinction. The findings have already prompted speculation that the Homo sapiens migrations into Europe may have come in at least two separate waves, rather than just one.
I'll add the abstracts later. This certainly seems to be incompatible with substantial Neandertal interbreeding. If humans and Neandertals were genetically compatible species, then why would they maintain very separate morphological populations for ~10ka? We would expect the two populations to quickly merge into one. Moreover, a longer period of interbreeding in West Eurasia would have left an excess of "Neandertal" ancestry in modern West Eurasians, something we simply don't observe.
"What the new dates mean", Benazzi summarised, "is that these two teeth from Grotta del Cavallo represent the oldest European modern human fossils currently known. This find confirms that the arrival of our species on the continent – and thus the period of coexistence with Neanderthals – was several thousand years longer than previously thought. Based on this fossil evidence, we have confirmed that modern humans and not Neanderthals are the makers of the Uluzzian culture. This has important implications to our understanding of the development of 'fully modern' human behaviour. Whether the colonisation of the continent occurred in one or more waves of expansion and which routes were followed is still to be established."
Nature (2011) doi:10.1038/nature10484
The earliest evidence for anatomically modern humans in northwestern Europe
Tom Higham et al.
The earliest anatomically modern humans in Europe are thought to have appeared around 43,000-42,000 calendar years before present (43-42 kyr cal BP), by association with Aurignacian sites and lithic assemblages assumed to have been made by modern humans rather than by Neanderthals. However, the actual physical evidence for modern humans is extremely rare, and direct dates reach no farther back than about 41-39 kyr cal BP, leaving a gap. Here we show, using stratigraphic, chronological and archaeological data, that a fragment of human maxilla from the Kent’s Cavern site, UK, dates to the earlier period. The maxilla (KC4), which was excavated in 1927, was initially diagnosed as Upper Palaeolithic modern human1. In 1989, it was directly radiocarbon dated by accelerator mass spectrometry to 36.4-34.7 kyr cal BP2. Using a Bayesian analysis of new ultrafiltered bone collagen dates in an ordered stratigraphic sequence at the site, we show that this date is a considerable underestimate. Instead, KC4 dates to 44.2-41.5 kyr cal BP. This makes it older than any other equivalently dated modern human specimen and directly contemporary with the latest European Neanderthals, thus making its taxonomic attribution crucial. We also show that in 13 dental traits KC4 possesses modern human rather than Neanderthal characteristics; three other traits show Neanderthal affinities and a further seven are ambiguous. KC4 therefore represents the oldest known anatomically modern human fossil in northwestern Europe, fills a key gap between the earliest dated Aurignacian remains and the earliest human skeletal remains, and demonstrates the wide and rapid dispersal of early modern humans across Europe more than 40 kyr ago.
Nature (2011) doi:10.1038/nature10617
Early dispersal of modern humans in Europe and implications for Neanderthal behaviour
Stefano Benazzi et al.
The appearance of anatomically modern humans in Europe and the nature of the transition from the Middle to Upper Palaeolithic are matters of intense debate. Most researchers accept that before the arrival of anatomically modern humans, Neanderthals had adopted several transitional technocomplexes. Two of these, the Uluzzian of southern Europe and the Châtelperronian of western Europe, are key to current interpretations regarding the timing of arrival of anatomically modern humans in the region and their potential interaction with Neanderthal populations. They are also central to current debates regarding the cognitive abilities of Neanderthals and the reasons behind their extinction1, 2, 3, 4, 5, 6. However, the actual fossil evidence associated with these assemblages is scant and fragmentary7, 8, 9, 10, and recent work has questioned the attribution of the Châtelperronian to Neanderthals on the basis of taphonomic mixing and lithic analysis11, 12. Here we reanalyse the deciduous molars from the Grotta del Cavallo (southern Italy), associated with the Uluzzian and originally classified as Neanderthal13, 14. Using two independent morphometric methods based on microtomographic data, we show that the Cavallo specimens can be attributed to anatomically modern humans. The secure context of the teeth provides crucial evidence that the makers of the Uluzzian technocomplex were therefore not Neanderthals. In addition, new chronometric data for the Uluzzian layers of Grotta del Cavallo obtained from associated shell beads and included within a Bayesian age model show that the teeth must date to ~45,000-43,000 calendar years before present. The Cavallo human remains are therefore the oldest known European anatomically modern humans, confirming a rapid dispersal of modern humans across the continent before the Aurignacian and the disappearance of Neanderthals.