Nothing against fossils, but when it comes to tracing the story of human evolution they’re taking a back seat lately to everything from DNA to lice, and even the DNAof lice. A few years ago scientists compared the DNA of body lice (which are misnamed: they live in clothing, not the human body) to that of head lice, from which they evolved, and concluded that the younger lineage split off from the older no more than 114,000 years ago, as I described in a cover story last year. Since body lice probably arose when a new habitat did, and since that habitat was clothing, that’s when our ancestors first needed a haberdasher. The Y chromosome has been an even greater source of clues to human evolution, showing among other things that the most recent common ancestor of all men alive today lived 89,000 years ago in Africa, and that the first modern humans walked out of Africa about 66,000 years ago and became the ancestors of everyone outside that natal continent.

The Y chromosome is at it again. Scientists reported this week that an analysis of Y chromosomes in a dozen African populations sheds light on one of the more controversial questions in human prehistory: did innovations such as animal herding spread because their inventors did, migrating to new places and teaching the natives new tricks, or because the idea spread on its own, as neighboring tribes noticed the new trick and adopted it, and then neighbors of those guys did the same, on and on until the idea had spread like wildlfire?

According to a paper in the online version of Proceedings of the National Academy of Sciences, pastoralism—cattle- and sheep-herding—arrived in southern Africa 2,000 years ago on a wave of human migration from eastern Africa, not by the spread of ideas to neighbors near and far.

“There's a tradition in archaeology of saying people don’t move very much; they just transfer ideas,” said genetic anthropologist Joanna Mountain of Stanford University, senior author of the paper with geneticist Peter Underhill. But in this case, at least, the people themselves moved.

Scientists knew about two prehistoric migrations of Bantu-speaking people from eastern Africa, where pastoralism first arose, to southern Africa: 30,000 years ago and again 1,500 years ago. But anthropological evidence showed that the first sheep and cattle herds existed in southern Africa 2,000 years ago. That suggested that the idea jumped from group to group (“hey, look what those guys are doing”) without the people themselves actually trekking south.

The Stanford scientists analyzed genetic variation on the Y chromosome, which is passed almost intact from father to son. The only change through the generations occurs through rare mutations. By counting and comparing mutations, geneticists can trace ancestries of living men, in this case 13 populations in Tanzania and in the Namibia-Angola-Botswana border region of southern Africa. In this case, it revealed a novel mutation in some men in both places, which implies that those men had a common ancestor. The novel mutation arose in eastern Africa about 10,000 years ago and was carried by migration to southern Africa about 2,000 years ago not by Bantu-speakers, in whom the mutation is absent, but in speakers of what’s called the Nilotic language. These unsuspected ancestors first brought herds of animals to southern Africa before the Bantu migration.

Why did they migrate south? Underhill suspects that a shift in rainfall 10,000 years ago caused some people to stay in rainy areas and grow crops, while others moved to dry regions and lived the nomadic life of herders, he and colleagues proposed in the June issue of the journal Antiquity.

CT scans have been done on mummies (showing that King Tut wasn’t murdered), dinosaurs (determining, for instance, what parasaurolophus sounded like) and other pieces of the past, and now scientists have put computed tomography (CT) technology to another nifty use: taking skull fragments of a rare extinct lemur which were found at sites thousands of miles apart and virtually assembling them to produce a nearly-complete skull.

The first fossil of the extinct lemur called Hadropithecus stenognathus, which last lived 2,000 years ago, was found in 1899 in Andrahomana Cave in Madagascar. Since then the jaw and partial skull have resided in Vienna, remaining annoyingly incomplete. But in 2003 scientists excavated new cranial fragments and limb bones of Hadropithecus. Alan Walker of Penn State, who happened to have CT scans of the Vienna skull in his lab for another project, realized that the new pieces might fit into the incomplete skull.

As Walker and colleagues describe in a paper in the early online edition of the Proceedings of the National Academy of Sciences Monday evening, they CT-scanned the new fragments and found that they fit into the Vienna skull perfectly.

That let them measure the lemur’s cranial capacity (115 ml.) and, using limb and trunk bones of the same guy, infer that it was as large as a large male baboon. Hadropithecus, it seems, had a relative brain size (as a fraction of body size) as large as some large monkeys, and one of the largest of any known prosimians (a group that includes lorises, lemurs and bushbabies). Hadropithecus, similar to today's sifaka, was one more piece of the stunning mosaic of biological diversity that Madagascar once supported, at least before the island was gripped by an extinction crisis.

Sad but true: attempts to use the DNA of extinct species to resurrect lost-long creatures—the quagga, the wooly mammoth and of course those Jurassic Park dinosaurs—hasn’t exactly worked (yet?), so I have a proposal. Scientists who study ancient DNA should abandon their current projects and focus on bringing back the one extinct life-form that would spice up modern life without, you know, leading to rampaging velociraptors: Vikings.

Extracting ancient DNA is tricky, what with modern DNA so ubiquitous. You risk contaminating your Neanderthal genes with, say, the genes of your grad student (and we all know how careless grad students are about leaving their genes lying around). But scientists in Denmark say they were really, really careful when they exhumed ten Viking skeletons, dating from about AD 1,000, from a burial site on the Danish island of Funen. Wearing protective suits, they removed teeth from the Vikings’ jaws at the moment the skeletons were unearthed, extracted DNA, and did all their analysis under carefully-controlled conditions to avoid contamination.

According to their report, being posted tonight on the Website of the journal PLoS One, they succeeded: the ancient DNA they extracted shows no evidence of contamination with the modern kind, Jørgen Dissing and colleagues at the University of Copenhagen say.

Sure, quaggas are cute and mammoths are majestic, but let’s be frank: think how much more fun it would be to clone Vikings. You know, even hunkier versions of, say, Viggo Mortensen (American mom, Danish dad).

It is the dream of children of any age to fly, and I don’t mean United or Delta. Yet if new research is right, then at least some of the magnificent flying reptiles of the Mesozoic called pterosaurs preferred to walk, thank you very much—at least for mealtime.

Pterosaurs called azhdarchids lived during the Upper Cretaceous (roughly 145 million to 65 million years ago), and include such crowd favorites as the gigantic Quetzalcoatlus northropi, with a wing span of 35 feet. Paleontologists studying azhdarchid fossils have concluded that they were “vulture-like scavengers, sediment probers, swimmers, waders, aerial predators, or stork-like generalists [or, most recently] . . . skim-feeders, trawling their lower jaws through water during flight and seizing aquatic prey from the water’s surface,” write scientists in a paper being posted in the journal PLoS One tonight.

Mark Witton and Darren Naish of the University of Portsmouth beg to differ. That model, they continue, “lacks critical support from anatomy and functional morphology.” For instance, these toothless pterosaurs lacked the compressed lower jaw and shock-absorbing apparatus that you need if you’re going to plow into a lake to score chow.

Instead, an analysis of these pterosaurs’ anatomy (weak jaws, ill-suited for crashing into water and snaring prey; poor neck flexibility, forcing the creatures to hold their necks like crocodiles rather than flex it like seagulls; wings better suited to soaring on rising thermals rather than flapping in precision-controlled flight down to the surface of a lake or sea) as well as their footprints (showing they were good walkers and runners, but with small padded feet better for strutting around on land than for wading around lake margins or swimming should they land on water) and the distribution of their fossils (in terrestrial more than marine sediments) adds up to one conclusion, the scientists say: azhdarchids (from the Uzbek word for “dragon”) used their long limbs to stalk, picking up small animals and other prey from the ground.

“All the details of their anatomy, and the environment their fossils are found in, show that they made their living by walking around, reaching down to grab and pick up animals and other prey,” said Naish. Their “bizarrely stiff neck has previously been a problem for other ideas about azhdarchid lifestyle, but it fits with our model, as all a terrestrial stalker needs to do its raise and lower its bill tip to the ground.”

Based on the fossils, Witton has produced images of the 10-foot-tall azhdarchid named Hatzegopteryxwould standing beside a man, a group of Quetzalcoatlus strolling around a prairie picking off baby dinosaurs for lunch, and one of them flying toward you.

You think you have big travel plans for the Memorial Day weekend? I guarantee they're nothing like what the first humans managed as they walked all over the globe after leaving their African homeland.

The human genome project has been a veritable treasure trove for scientists trying to tell the story of humankind’s migrations out of Africa. A couple of terrific books have chronicled this, and the use of genetics to reconstruct human history was a focus of a cover story we did last year. The fun part is when genetics throws a wrench into supposedly settled accounts, and that’s what a paper posted today in the open-access journal PLoS Genetics does.

In it, scientists from the University of Oxford and University College Cork describe a new technique they developed. It analyzes not just the Y chromosome, as many studies using genetics to trace human history do, but parts of chromosomes across the entire human genome. The details are complicated, but the bottom line is an ability to probe further back in time and identify smaller genetic contributions.

The technique confirms the out-of-Africa model, in which all human populations outside that continent today are the descendants of a single pulse of wanderers who left Africa. Hominids who originally lived in the regions of Asia and Europe colonized by the migrants contributed nothing to the modern gene pool, which is a polite way of saying that our ancestors wiped them all out (or at least prevented them from mating). Or, as I wrote in the cover story:

“The first modern humans—and therefore, unlike the earlier wave of Homo erectus into Asia a million years ago, the ancestors of everyone today outside Africa—departed Africa about 66,000 years ago. These pilgrims were strikingly few.... The best estimate: 2,000 men. Assuming an equal number of women, only 4,000 brave souls ventured forth from Africa.”

Now the technique is throwing up surprises about what happened next. Among them:

*The most northerly East Asian population that the scientists analyzed, Siberians called the Yakut, carry genes of the most northerly European population, the Orcadians (whose descendants live in the Orkney Islands), suggesting that northern Europeans walked into north Asia and hooked up with native peoples there.

*Populations in Central Eurasia have genes from the Near East (Bedouins and Palestinians) and even Kenyan Bantus.

*In Europe, the most ancient populations are the French, followed by the Tuscans and then other Italians, all of whom trace their ancestry to north Africans called Mozabites, today called Berbers, and to several Near Eastern and Central Asian populations. Europeans have more genetic ancestors than any non-European population, making Europe the world’s true melting pot.

*The youngest Europeans are the Sardinians, Russians, Orcadians and Basques—which makes sense, since they are all at the geographic extremes of the continent. People arrived there last. All four have big genetic contributions from the Near East and Central Asia, suggesting multiple waves of migrants into Europe.

*In the Americas, the Colombians are the oldest population. They can trace 47 percent of their ancestry to the Hazara of East Asia but, oddly, they also have genetic contributions from the French. That probably reflects intermarriage after Europeans arrived in the New World.

*The Pima are the oldest people of North America. They trace their ancestry to the Colombians but also, surprisingly, to Mongolians, who are not ancestors of the Colombians. That suggests multiple distinct colonizations into North America from Asia.

*The Mayans have Bantu and Tuscan donors, presumably due to intermarriage after the Europeans arrived.

For two cool little movies of all this, scroll to the bottom of the paper and click on Movie 1 and Movie 2.

Somehow, the end of the line for ancient human ancestors in Europe has long attracted more attention than the beginning, what with painstaking research as well as rampant speculation about how long Neandertals hung on in Spain and Portugal and whether they interbred with Homo sapiens. (If the latter, then modern humans have a little bit of Neandertal in them, something I find easy to believe every time I ride the subway.)

But now scientists are rewriting the beginning of that timeline, too. Teeth and a jaw bone discovered in Atapuerca, in northern Spain, they say, mean that the first direct human ancestors—of Neandertals as well as Homo sapiens (including Cro Magnon, for you Clan of the Cave Bear fans) and the rest—reached Europe 1.2 million years ago, not 800,000 years ago as had long been thought.

The first humans left their natal continent of Africa about two million years ago, walking out of the northeast corner through what is now Egypt. They turned right, anthropologists have long believed, probably because it was too cold and tough-going toward the north and west. Only later did some of the hominids leaving Africa make it to Europe—but that “later” has been vague.

With the stone tools, animal remains and human teeth and jawbone found in Spain by a team led by Eudald Carbonell of the Institut Català de Paleoecologia Humana i Evolució Social in Tarragona, Spain, “later” now means 1.2 million years old. As the team reports today in the journal Nature, these first Europeans were enthusiastic carnivores; the animal bones found along with the human ones, and dated to the same 1.2 million years, show signs of a butcher’s fine hand.

Who were these pioneers? The oldest known hominid fossils in Eurasia were found in Dmanisi, Georgia, and have been dated at 1.8 million years. Paleoanthropologists believe that Homo ergaster was the species that left Africa, and that’s who—along with, perhaps, another species—settled in Dmanisi. But Carbonell and his team conclude that the Atapuerca fossils look sufficiently different to be a distinct species, and so give them the name Homo antecessor.

She—for the fossil jawbone and teeth seem to come from a female—is now the best candidate for the last common ancestor of Neandertal and modern humans, Homo sapiens.

Antecessorapparently knew how to hunt, make stone tools with sharp edges for butchering their prey, and hammer. They probably doubled back from Asia and headed west into Europe. It is possible, though, that they represent a second wave of out-of-Africa wanderers, turning left at Egypt—rugged terrain and cold climate be damned. The new date for the first Europeans means there's a lot more fossils—400,000 years worth—to be found that anthropologists dreamed of, all of them offering the possibility of revealing how the children of a little band of primitive primates that left Africa 2 million years ago came to rule the world.

Although the Europeans got silver, gold, converts and tobacco out of their conquest of the New World in the 1500s, the Native Americans got nothing but genocide, as what UCLA biologist Jared Diamond called “guns, germs and steel” killed an estimated 90 to 95 percent of the Native Americans—a horrifying 20 million souls. Nothing was more one-sided than the direction that germs traveled. European conquistadors thoughtfully introduced smallpox, influenza and measles, against which the populations of the Americas had no immunity. Result: disease killed more of them than guns or steel.

Only one disease, scholars have long suspected, might have made the trip east to Europe: syphilis. Circumstantial evidence supported an America-to-Europe trajectory: the first recorded epidemic of syphilis occurred in Europe in 1495, upon Columbus’s return. Although some medical historians have argued that the syphilis pathogen (the bacterium Treponema pallidum) existed in Renaissance Europe long before Columbus returned from his voyage to the New World, the most sophisticated study to date, being published today in the journal PLoS Neglected Tropical Diseases, concludes otherwise: a genetic analysis of the treponeme bacteria supports the “Columbian theory” of syphilis’s origins in the Americas. Call it Montezuma’s revenge, squared.

To trace the origins of syphilis, scientists have mostly studied old bones, which preserve evidence of late-stage syphilis. But because it is tough to pinpoint the exact age of the bones, these studies have been inconclusive. Kristin Harper of Emory University and colleagues therefore studied 21 genetic regions in the genomes of 26 geographically disparate strains of treponemes. Based on how much the different strains had diverged from the basic genetic blueprint, the scientists were able to create a family tree for treponemes. It showed that the strains that cause venereal syphilis originated most recently. Their closest relatives were strains collected in South America that cause the disease yaws. Together, they say, the analyses supports the idea that syphilis originated in the Americas.

But wait. The syphilis that was present in the Americas when Columbus landed (there was a treponemal infection in the Dominican Republic when he arrived) might not have been venereal—that is, spread sexually. “Therefore, it is not clear whether venereal syphilis existed in the New World prior to Columbus’s arrival,” write the scientists. “While it is possible that Columbus and his crew imported venereal syphilis from the New World to Europe, it is also possible that the explorers imported a non-venereal progenitor that rapidly evolved into the pathogen we know today only after it was introduced into the Old World.” If so, then the Americas provided the ancestral germ, but that germ assumed its deadly venereal form only after it became ensconced in Europe.

Critics of the new study say the analysis compared too few DNA sites to reach the conclusions it did, arguing that “no evolutionary order” for the syphilis family of bacteria can be inferred, and urging “caution” in accepting Harper’s claim. Still, this study, combined with earlier work, presents the strongest evidence that the Native Americans got at least a modicum of revenge on their killers.

Nigersaurus: 500 teeth and a vegetarian diet. Photo by Mike Hettwer, courtesy of Project Exploration. ©2007 National Geographic.

Discovered in 1999 in the Sahara desert by National Geographic Explorer-in-Residence Paul Sereno of  the University of Chicago, Nigersaurus taqueti was a vegetarian originally known only by a few distinctive hand bones. But further excavation has fleshed (boned?) him out.

Those Geico (and now ABC) cavemen might not be as fictional as you’d think (well, okay, the tennis playing and working on a thesis, maybe). I’m talking about talking.

Language is supposed to be the trait that distinguishes modern humans both from other animals and from our grunting ancestors. But a new study, published online today in Current Biology, suggests that while we might be special, we might not be unique. Contrary to the claim that the only gene known to play a role in speech and language arose in its current form some 20,000 years ago—long after modern Homo sapiens and Neanderthals diverged evolutionarily—it looks like Neanderthals had this FOXP2 gene. That raises the possibility that Neanderthals possessed some of the biological machinery necessary for language.

“From the point of view of this gene, there is no reason to think that Neanderthals would not have had the ability for language,” said Johannes Krause of the Max Planck Institute for Evolutionary Anthropology. But since FOXP2 is not the only gene that underlies the capacity for language, Neanderthals would presumably have needed them, too, in order to have the gift of gab.

For the new study, Krause and his colleagues extracted DNA from Neanderthal fossils found in a cave in northern Spain, one of the species’ last redoubts before going extinct. They then identified and sequenced the Neanderthal FOXP2 gene. It was identical to the version found in modern humans.

Other studies of Neanderthal genes have turned out to be flawed due to contamination (what was thought to be an ancient gene actually came from DNA lying around the lab, as in sloughed-off skin cells). The scientists say they have taken pains to make sure this didn’t happen, including by sequencing parts of the Neanderthal Y chromosome, which was found to be different from the version in today’s men.

The finding, say the researchers, “establishes that these changes [in FOXP2 that distinguish it from the chimp version and, thus, presumably help confer the capacity for speech and language] were present in the common ancestor of modern humans and Neanderthals.” Our lineage might have been a much chattier past than anyone suspected.

This guy was not playing by the rules.

Most theories of dinosaur evolution say that carnivorous dinosaurs, the ancestors of today’s birds, got smaller as they became more bird-like. But the remains of a new species and genus of dinosaur, discovered in Inner Mongolia and announced at a press conference in Beijing this morning, throw a wrench into that idea.

Gigantoraptor, as he has been named, is surprisingly bird-like in his skeleton, and probably had feathers. He lived in the Late Cretaceous about 70 million years ago, and an analysis of his skeleton puts him in the same family as the beaked, bird-like Oviraptor, say Xing Xu of the Chinese Academy of Sciences, who led the discovery, and colleagues. By all rights, a birdlike dinosaur should have been evolving toward the size of birds living today—if not crows, then at least emus.

Gigantoraptor stood about 3.5 meters (10 feet) high at its shoulder, twice the height of a person today. He stretched 8 meters (24 feet) in length and weighed in at 1,400 kilograms (3,000 pounds). Or, in an artist’s conception,

Artist's reconstruction of Gigantoraptor with much smaller feathered ornithomimids. Credit: Zhao Chuang and Xing Lida/IVPP

 (Our boy is the dino on the far left.)