Clothing Origins

A study of the evolution of lice has been used to date the possible origin of human clothing.

Previously, researchers have opined that clothing was developed from 40,000 to 1.2 million years ago. The 40,000 year old time was considered the strongest candidate. But there is little direct evidence for the first clothing.

These estimates took into account the fact humans lost their full-coat body hair about 1.2 million years ago; and hide scrapping – indicating development of leather – has been traced to about 780,000 years ago.

Now the lice study suggests the origin of clothing was 190,000 years ago, Andrew Kitchen of Pennsylvania State University told the AAPA meeting. This would put clothing development in the early days of modern humans and Neanderthals.

Kitchen used a Bayesian coalescent modeling approach to examine mutations in a dataset of human head and clothing lice. His group found that head and clothing lice initially diverged at 190,000 years ago, inferred as the time of the first clothing.

“This suggests that the use of rudimentary clothing likely originated with anatomically modern humans in Africa, even though several species of archaic Homo already occupied northern latitudes at that time,” he says.

Skulls Repatriated

Historically, repatriation of human remains from museums to native groups can be contentious. A recent international repatriation case shows how smoothly a transfer can go.

The remains included a dozen skulls, a skeleton and bloodied artifacts taken by an anthropologist in 1902 from Yaquis in Sonora, Mexico – after federal troops killed at least 125 men, women and children at Sierra Mazatan. In that era, the Yaquis were enslaved for field work and brutalized by the dictatorial Mexican government.

The repatriation by the American Museum of Natural History in New York to Mexico last November is detailed in an AAPA poster by Heidi Bauer-Clapp, a doctoral student at the University of Massachusetts at Amherst. Her Amherst co-author Ventura Perez initiated the project after learning the remains and bloody blankets were at the American Museum.

Beginning in 2007, Perez worked with Andrew Darling of the Gila River Indian Community in Arizona, who put the team in touch with Yaquis near the massacre site east of Hermosillo, Sonora. Yaqui tribal members traveled to New York for a ceremony, and then the bones were returned for internment in Vicam, Sonora.

Early anthropologist Ales Hrdlicka cut off the heads and defleshed them shortly after the massacre. The bones then were stored away at the museum with little scrutiny, noted Bauer-Clapp.

She said the crude collection methods limited the ability to study the living experiences and stresses endured by the victims. Recent tests confirmed the blood was human, but no DNA analysis was conducted.

Genetics Training

Researchers from the American Association for Anthropological Genetics [AAAG], a 70-person organization also meeting with the AAPA, announced it is planning a series of annual educational workshops to provide instruction to anthropologists on rapidly developing genetics and genomics techniques.

AAAG also sponsored a seminar on social/environmental aspects of anthropology research increasingly meshing with genetic techniques on human variation, population structure, phenotype analysis [including race], and disease susceptibility.

Posted on behalf of Rex Dalton

In the heart of the United States’ historically-rich southwest, three anthropological organizations met this week in Albuquerque, New Mexico, to share studies of humans, primates and associated lifestyles.

The main session (14-17 April) was the 79th annual meeting of the American Association of Physical Anthropology (AAPA), in conjunction with the 35th annual Human Biology Association and the 37th annual Paleopathology Association. It was announced at the meeting that the Paleopathology Association now will have an official publication, the International Journal of Paleopathology, to be published by Elsevier. The first edition is slated for later this year.

At the AAPA meeting, there was a strong theme of genetics in the program organized by this years’ program chair, Lorena Madrigal of the University of South Florida in Tampa. In a time when hardly a month goes by without another release of genetics studies linking ancient peoples with those of today, the theme isn’t a surprise. But the extent to which human genome probing is altering the anthropological field appears unmatched. AAPA President Dennis O’Rourke, a geneticist at the University of Utah in Salt Lake City, put this in perspective with a talk noting how three recent instances of ancient DNA analysis adds an unprecedented perspective on anthropological field work. Those cases were the first complete ancient human genome from a 4,000-year-old hair specimen of a Saqqaq in Greenland, whose lineage was traced to Siberia; analysis of DNA in feces from Paisley Caves in Oregon, reflecting Pre-Clovis peoples at 14,000 years ago; and DNA recovered from bone of a 9,300-year-old male from On Your Knees Cave on an island off southeastern Alaska. Interestingly, the On Your Knees Cave specimen has already been repatriated to the local Native American tribes – a process made quicker by the ready availability of DNA analysis.

For anthropologists interested in the paleo record, the big disappointment was the withdrawal on 15 April of a talk by University of Michigan at Ann Arbor researchers and colleagues on a new primate fossil from Saudi Arabia dated to 28-29 million years ago. The team that also includes researchers from Saudi Geological Survey decided not to discuss the research before it is published in a peer-reviewed journal. A general description of the study is included in the AAPA abstract book. Based on that abstract, the details are as follows:

Not much is known about the timing and origin of old world monkeys and hominoids, our ancestors. Lead author Iyad Zalmout of Michigan reports the discovery of a partial cranium from the Shumaysi Formation in western Saudi Arabia. The features of the specimen are interpreted as “an advanced stem catarrhine close to the ancestry of apes and old world monkeys.” This fossil is allowing the authors to test hypotheses about the ancestral characteristics of old world monkeys and apes. Such analyses indicate that the old world monkey/ape split “could have occurred as early as the beginning of the late Oligocene, but likely not earlier.” Stay tuned for the full description likely in the coming weeks.

There also was more on early primates from Lauren Gonzales of New Mexico State University in Las Cruces and colleagues – who reported on the brain of Victoriapithecus macinnesi, from the 15 million year old Maboko formation in Kenya. The report is based on the most complete and minimally distorted skull of a eucatarrhine known prior to 6 million years ago. The skull was discovered [Nature 388, 368-371 (24 July 1997)] by Gonzales co-authors. The V. macinnesi brain analysis was in a poster. CT scans showed the large male had a smaller brain than anticipated. But the brain had a particularly large olfactory lobe, indicating keen sense of smell and sight. This has prompted the authors to hypothesis that such vision acuity may have driven the subsequent development of the frontal lobe – which is associated with advanced social intelligence in higher primates. And thus the resulting evolutionary decrease in olfactory lobe size in later anthropoids.

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The American Association for the Advancement of Science puts on one of the biggest science shindigs of the year, and Nature journalists will soon be blogging from the meeting to bring you the freshest morsels of research news and gossip.

I’m writing this after a few drinks (which, as you’ll soon see, is perfectly appropriate) and after being inspired by Simon Conway Morris’s talk on the origin of body plans. I wish I could do Conway Morris’s talk justice in this blog – he is an eloquent, and funny, speaker. Suffice it to say that he recounted some of his arguments against Gould (read about that here); fought back, good-naturedly, at several other speakers at this conference who have called him wrong about some particular matters of creature identification; threatened to drink a bottle of commemorative ‘Shale Ale’ whilst at the podium in spite of Canada’s draconian laws against drinking in public; and responded to one confession of love. Of course, he also addressed some serious points of biology, concluding that perhaps, “at long last, biology is going to become predictable”. There’s one prediction I would bet money against.

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Martin Brasier of Oxford University jokingly referred to the ‘MOFAOTYOF Principle’ in his talk – the ‘My Oldest Fossils Are Older Than Your Oldest Fossils’ phenomenon. He makes fun of it (such competitions can perhaps get a bit silly), but it is the business that Brasier and his team are in – hunting down those oldest fossils of the old.

Certainly you can’t get older than the Ediacaran when it comes to animal fossils, and this was the subject of Brasier’s talk – the strange squished creatures preserved in the rocks of Mistaken Point, Newfoundland. At the end of his talk, Brasier threw up a slide showing some ‘trace fossils’ – the fossilized tracks that some worm-like or snail-like creature left behind. Such tracks are more common in younger fossil beds, when animals were more likely to be mobile (the most commonly talked about Ediacaran beast looks like a feather stuck in the seabed, and certainly didn’t get around too much). And they’re more common in shallow waters. If such tracks are from the Ediacaran deep waters, as implied, then that would be quite exciting to those in the field. It could even push back the date of complex mobile creatures – things that move intentionally in a single direction, perhaps in search of food, with a sensory system and complex muscles – by tens of millions of years. Maybe. “A lot of people have looked at a lot of rock very hard and not seen anything like this,” I overheard Guy Norbonne, an Ediacarian expert, say over coffee. “I understand it’s under review. Let’s see the paper, and see how it stands up.”

Brasier sees a bit of a shift in how people are looking at the Ediacaran. At first there was an awed acceptance that all these squishy creatures must have been the ancestors of modern animals (so there would be a soft coral, and a squidgy early worm, etc). Then the Ediacaran creatures were seen as a ‘failed experiment’, most of which went extinct. Now there is a more sober period of working out what they all were, and which ones died out and which lived on, Brasier says. This shift is one of the reasons he wrote his recent book Darwin’s Lost World, about the Ediacaran fossils (Darwin lamented that pre-Cambrian fossils had never been found; but they have been found since, and so are not a ‘lost world’ to us).

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I was slightly shocked to see a slide of ‘fossilized brains’ from the Cambrian thrown up on a slide. Brains? From the Cambrian? Turns out I was right to be shocked. “People find it hard to swallow” says Nicholas Strausfield, a neuroanatomist from the University of Arizona. He was trawling through Burgess Shale fossils of Waptia – a small shrimp-like creature from the Cambrian – looking for hints of the evolutionary relationship between insects and crustaceans, when he found 3 samples that seemed to have brain-shapes in them. “I have flattened a lobster brain, and it looks like that,” he says. You can’t tell too much from these fossils, except that the brain was apparently big enough to handle some complex sensory information from the antenae and simple eyes. Still, it’s fascinating. Strausfield (who, as the recipient of a McArthur grant, unofficially counts as a ‘genius’) switched from looking at insects to crustaceans on the principle that you ought to be able to eat what you study. Sadly, he notes, Waptia is so small it wouldn’t even make a good soup.

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The annoying thing about fossils is trying to work out what the heck the creature looked like before it was trapped in a mudslide, lost some limbs, got squashed flat, and was chemically altered by millennia of burial. This is not easy. And as Robert Sansom of the University of Leicester points out, it’s made extra difficult by the fact that some discriminating features used to identify these creatures decay faster than others. That introduces a bias in how organisms are classified, he warns. His group is doing lab tests of decay rates of different bits and pieces of animals to sort these biases out.

The lucky thing is that Burgess Shale fossils and others from the same time period around the world are strangely well-preserved. I had assumed that this was just a lucky accident of some Cambrian beasts being swallowed by a mudslide, and Walcott finding the result. But it seems to be more complicated than that. The preservation of organic carbon from these beasties is a highly unusual phenomenon, and is very rare (possibly absent?) in the fossil record for animals of younger eras. Why is this? No one knows for sure. But it might have been a combination of those animals being swamped with fine-grained clay that kept the oxygen out, and the oceans being low in sulphate, which stopped other bacteria from eating up the remains. An intriguing thought, with evidence to support it from Emma Hammarlund of the University of Southern Denmark.

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Some of the weirder Ediacaran species might not be species after all, Alexander Liu of Oxford University has told the conference. There’s a brand of squidgy Ediacaran fossils known collectively as ‘pizza discs’. They are all round, and have bumpy bits – of up to 1-cm height in the fossil record – randomly scattered in the middle. These bumps are not consistent from one pizza disc to the next – each disc is individual. This makes it hard to identify the characteristics that define the creature that left the fossil print. So hard, in fact, that Liu wonders if it’s not a specific creature after all. Some tell-tale hints in some pizza discs hint that maybe they are the slightly-decayed remnants of other, already-known species, he told the conference. Liu, who works in Martin Brasier’s group, has even rotted some modern jellyfish and seaweed bits in the lab and made modern fossils of them, to confirm that this does indeed create irregular, lumpy shapes (no huge surprise there). His conclusion – that blobby bits that don’t look like much might, in fact, be blobby bits that aren’t anything much special – is so intuitively obvious that I can’t help but think he’s right. Depending on who you talk to, though, downgrading the Pizza disc from a creature to a bit of garbage might be slightly controversial.

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Yet more history from Desmond Collins, who talked today about the work that has gone on in the Burgess Shale since the 1970s or so. Collins himself was in charge of many further explorations of the shale, and even has a quarry named after him (as does the original discoverer Charles Doolittle Walcott, and a handful of others, but only a handful). Collins is clearly on a first name basis with both all the people who have explored the shale, and also all the creatures who have turned up in the rocks. He showed a fabulous slideshow of weird and wonderful creatures preserved in the shale, most of which you can see in the Royal Ontario Museum’s online photo collection. Surprisingly (to me), many of the creatures revealed have still not been properly described – including the one called the ‘Collins monster’.

Collins’ stories are full of freak snow storms during trips up to the shale, accidental finds of great fossils, and lovely little details that make the stories come alive: from the rat (which he also knows the name of… Robert I think it was) who licked their dishes clean for them when they were short on water, to the goats who licked the salt left on the rocks by the camp’s mandated bathroom site (the goats would unfortunately kick bits of shale onto the camp in the process, until the researchers got permission from the park authorities to move the camp and pee wherever they liked). In 1995, while shoveling out vast amounts of fallen shale from the original quarry site, they found a block of ice encasing newspapers left behind on Walcott’s expeditions.

Photos show how the Burgess Shale sites have changed and expanded over time – the original Walcott quarry is now some 3 times bigger than it originally was, thanks to researchers attacking the rocks with crow-bars, jack hammers and circular saws (they weren’t allowed to use dynamite, as Walcott did, much to Collins’ dismay). About half of Walcott’s original quarry ledge has been preserved for historical reasons. The rest has been hacked away to reveal yet more finds. Looking at the panoramic shots of the mountains, one can’t help but think there must be many, many more possible quarry sites – it’s fantastic to imagine what weird wonders remain to be found.

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Quote of the day goes to Kevin Peterson of Dartmouth College, who began his talk with a dedication to Wonderful Life, the book that popularized Cambrian creatures. “If it weren’t for Wonderful Life we all wouldn’t be here. Or at least I wouldn’t be,” he said. “I brought this book to a bar in Montanna and read it in one sitting, over 12 beers. I developed my first man crush – I was in love with Simon Conway Morris.” (He means this as a joke, of course… no actual romance here). Conway Morris was one of the researchers who reinterpreted the Burgess Shale fossils in the 1960s, unveiling their truly bizarre characteristics, and is giving a talk here tomorrow… perhaps someone should warn him of Peterson’s unrequited feelings.

Meanwhile Peterson has gone on to work on annelids – which he confesses are really just ‘boring segmented worms’. There has been a problem in the worm world that genetic evidence gave a different sort of family tree than did morphology… in fact genetics seemed to put molluscs and other distinctly non-wormy creatures nested in within marine worms, which was surely not right. Indeed it would have meant there were a bunch of worms missing from the Cambrian fossil record. Peterson’s group has been using micro-RNA evidence to sort it out, showing that the earlier genetic evidence was simply wrong in this part of the family tree (though he still doesn’t know why). Worm dilemma sorted. Micro-RNA analysis, it seems, has a great potential for sorting out such family tree mysteries, though of course you need modern, living species to analyze – it doesn’t exactly help to identify Ediacarian creatures.

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