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What's new with Neanderthals?

Bayle et al. / PNAS
Scientists created these virtual 3-D reconstructions of 30,000-year-old teeth.


Did our extinct Neanderthal cousins have an artistic bent, and did they interbreed with modern humans? Newly published research seems to support affirmative answers to both questions, but those answers are far from final.

The fresh findings appear this week in two reports written by overlapping teams of researchers and published by the Proceedings of the National Academy of Sciences.

One study focuses on bones and marine shells found at 50,000-year-old Neanderthal cave settlements in southeast Spain. The other study looks at the teeth of a 30,000-year-old human skeleton from Portugal.

Did they do it?
One of the big questions about the Neanderthals is whether they had sex with our human ancestors. Evolutionary theory dictates that both species - Homo sapiens and Homo neanderthalensis - diverged from a common ancestor perhaps 700,000 years ago. However, paleoanthropologists are still debating whether the two species interbred when they came in contact in Europe about 40,000 years ago. Some go so far as to suggest that Neanderthals disappeared not because they were killed off by early humans, but because they were genetically absorbed into our own species.

The analysis of teeth from the skeleton of a 4- to 5-year-old human child, unearthed more than a decade ago at Portugal's Abrigo do Lagar Velho site, suggests that the humans of 30,000 years ago had more in common with Neanderthals than was previously thought.

 

Univ. of Bristol
  The 30,000-year-old child skeleton found in Portugal was nearly complete.


Researchers led by Priscilla Bayle of France's Museum of Natural History used X-ray micro-tomography to create 3-D images of the child's teeth. They found that the front teeth were delayed in their degree of formation, compared with the state of the teeth farther back on the jaw. The front teeth also had more dentin and pulp than the teeth of more recent humans, but less enamel.

These characteristics don't fit the pattern seen in today's human population, or even the pattern for 12,000-year-old human teeth. They come closer to fitting the pattern for Neanderthals, the researchers said.

The University of Bristol's João Zilhão, who found the skeleton and is a co-author of the study, said in a news release that the tooth analysis joins a growing body of evidence "that shows these 'early modern humans' were 'modern' without being 'fully modern.'"

The university said the report "raises controversial questions about how extensively Neanderthals and modern human groups of African descent interbred when they came into contact in Europe."

However, the study itself stops short of directly addressomg those questions. Instead, the researchers say their findings "reinforce the complex nature of Neanderthal-modern human similarities and differences, and document ongoing human evolution" even after the rise of modern humans. They suggest further studies of juvenile teeth, going back 100,000 to 200,000 years, could make a significant contribution to charting the human family tree.

Neanderthal artistry
In a second study, also published by PNAS, Zilhão takes more of a head-on approach to another big question surrounding the Neanderthals: Did human invaders outsmart them? Some scientists have suggested that modern humans prevailed over Neanderthals because they were better at symbolic thinking, based on the evidence that humans created cave paintings and ornaments back then.

But when Zilhão and his colleagues looked at the bones and shells found in two Spanish caves inhabited by Neanderthals 50,000 years ago - 10,000 years before the first signs of modern humans turn up in Europe - they saw evidence of ornaments and painting that they called "literally, rock-solid."

 

Zilhão et al. / PNAS
  The top photo shows both sides of a perforated shell (Pecten maximus) found in a Spanish cave. The lower pictures focus in on orange pigment stains.


Some of the shells they found were perforated, as if they could be worn on a string. That in itself doesn't prove anything, because such perforations could occur naturally or as the result of harvesting the molluscs for consumption. But the scientists also saw signs of mineral-based pigments being applied to the shells, in some cases right over the jagged edge of a perforation.

If the researchers' analysis is correct, the Neanderthals could have mixed up reddish goethite and hematite, yellow siderite and natrojarosite, black charcoal and sparkly pyrite to create a spectrum of paints. Some of the shells might have served as dishes holding the paint. The anthropologists even found a horse bone with flecks of orange pigment on the end.

"This naturally pointed bone may have been used as a stiletto for the preparation or application of mineral dyes or as a pin or awl to perforate soft materials (e.g., hides) that were themselves colored with such dyes," the researchers wrote.

In the past, skeptics have downplayed evidence of Neanderthal-made ornaments by saying that they may have actually been created by the human invaders, or that the Neanderthals were imitating human behavior without understanding what they were doing. The fact that this evidence was dated back to a time before humans arrived boosts the view that the Neanderthals had the smarts to come up with symbolic thinking on their own.

"The Iberian finds show that European Neanderthals were no different from coeval Africans in this regard, countering genetic/cognitive explanations for the emergence of symbolism and strengthening demographic/social ones," the researchers wrote.

All this doesn't settle the love-'em-vs.-fight-'em debate, but it does provide additional ammo for those who argue the Neanderthals were more like us than we sometimes give them credit for. That goes particularly for redheads. Check out these other reports on the Neanderthal mystery, and feel free to weigh in with your comments below.

More on the Neanderthals:


The researchers behind the tooth study include Bayle and Zilhão as well as Roberto Macchiarelli (Université de Poitiers, France), Erik Trinkaus (Washington University, St. Louis), Cidália Duarte (Câmara Municipal do Porto, Portugal) and Arnaud Mazurier (CRI-Biopôle-Poitiers, France).

The researchers behind the study of shells and bones include Zilhão as well as Diego Angelucci (Universita degli Studi di Trento), Ernestina Badal-Garcia and Valentin Villaverde (Universidad de Valencia), Francesco d'Errico (CNRS and University of the Witwatersrand), Floreal Daniel and Lare Dayet (Universite de Bordeaux), Katerina Douka, Thomas Higham and Rachel Wood (University of Oxford), Maria Jose Martinez-Sanchez, Carmen Perez-Sirvent and Josefina Zapata (Universidad de Murcia), Ricardo Montes-Bernardez (Fundacion de Estudios Murcianos Marques de Corvera), Sonia Murcia-Mascaros and Clodoaldo Roldan-Garcia (Universidad de Valencia) and Marian Vanhaeren (CNRS).

The PNAS reports use the spelling "Neandertal" rather than Neanderthal, but I've revised that spelling in the quotes above for consistency's sake.

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