Tuesday, April 19, 2011

Right-handedness prevailed 500,000 years ago

Right-handedness is a distinctively human characteristic, with right-handers outnumbering lefties nine-to-one. But how far back does right-handedness reach in the human story?
Right-handedness prevailed 500,000 years ago

Researchers have tried to determine the answer by looking at ancient tools, prehistoric art and human bones, but the results have not been definitive.

Now, David Frayer, professor of anthropology at the University of Kansas, has used markings on fossilized front teeth to show that right-handedness goes back more than 500,000 years. He is the lead author (with colleagues in Croatia, Italy and Spain) of a paper published this month in the British journal Laterality.
His research shows that distinctive markings on fossilized teeth correlate to the right or left-handedness of individual prehistoric humans.
“The patterns seen on the fossil teeth are directly and consistently produced by right or left hand manipulation in experimental work,” Frayer said.
The oldest teeth come from a more than 500,000-year-old chamber known as Sima de los Huesos near Burgos, Spain, containing the remains of humans believed to be ancestors of European Neandertals. Other teeth studied by Frayer come from later Neandertal populations in Europe.
“These marks were produced when a stone tool was accidentally dragged across the labial face in an activity performed at the front of the mouth,” said Frayer. “The heavy scoring on some of the teeth indicates the marks were produced over the lifetime of the individual and are not the result of a single cutting episode.”
Overall, Frayer and his co-authors found right-handedness in 93.1 percent of individuals sampled from the Sima de los Huesos and European Neandertal sites.
“It is difficult to interpret these fossil data in any way other than that laterality was established early in European fossil record and continued through the Neandertals,” said Frayer. “This establishes that handedness is found in more than just recent Homo sapiens.”
Frayer said that his findings on right-handedness have implications for understanding the language capacity of ancient populations, because language is primarily located on the left side of the brain, which controls the right side of the body, there is a right handedness-language connection. 
“The general correlation between handedness and brain laterality shows that human brains were lateralized in a ‘modern’ way by at least half a million years ago and the pattern has not changed since then,” he said. “There is no reason to suspect this pattern does not extend deeper into the past and that language has ancient, not recent, roots.”
source and photo credit :  http://www.news.ku.edu/2011/april/18/righthanded.shtml

South America's oldest textiles identifed by carbon dating

Textiles and rope fragments found in a Peruvian cave have been dated to around 12,000 years ago, making them the oldest textiles ever found in South America, according to a report in the April issue of Current Anthropology.


The items were found 30 years ago in Guitarrero Cave high in the Andes Mountains. Other artifacts found along with the textiles had been dated to 12,000 ago and even older. However, the textiles themselves had never been dated, and whether they too were that old had been controversial, according to Edward Jolie, an archaeologist at Mercyhurst College (PA) who led this latest research.


The cave had been disturbed frequently by human and geological activity, so it was possible that the textiles could have belonged to much more recent inhabitants. What's more, the prior radiocarbon dates for the site had been taken from bone, obsidian, and charcoal—items that are known to sometimes produce inaccurate radiocarbon ages. According to Jolie, charcoal especially can produce dates that tend to overestimate a site's age.


"By dating the textiles themselves, we were able to confirm their antiquity and refine the timing of the early occupation of the Andes highlands," Jolie said. His team used the latest radiocarbon dating technique—accelerated mass spectrometry—to place the textiles at between 12,100 and 11,080 years old.


The textile items include fragments of woven fabrics possibly used for bags, baskets, wall or floor coverings, or bedding. They were likely left by settlers from lower altitude areas during "periodic forays" into the mountains, the researchers say. "Guitarrero Cave's location at a lower elevation in a more temperate environment as compared with the high Andean [plain] made it an ideal site for humans to camp and provision themselves for excursions to even higher altitudes," Jolie and his colleagues write.


These early mountain forays set the stage for the permanent settlements that came later—after 11,000 years ago—when the climate had warmed, glaciers receded, and settlers had a chance to adapt to living at higher altitudes.


Jolie's research also suggests that women were among these earliest high altitude explorers. Bundles of processed plant material found in the cave indicate that textile weaving occurred on site. "Given what we know about textile and basket production in other cultures, there's a good possibility that it would have been women doing this work," Jolie said.


"There's an assumption that these early forays into the mountains must have been made exclusively by men," he added. "It appears that might not be the case, though more work needs to be done to prove it."


Source : http://www.journals.uchicago.edu/

Mapping of Maya's "Holtun" site in Central Lakes region of Guatemala locates triadic pyramid, astronomical observatory, ritual ball court, residential mounds, plazas




Archaeologists have made the first three-dimensional topographical map of ancient monumental buildings long buried under centuries of jungle at the Maya site "Head of Stone" in Guatemala.


The map puts into 3-D perspective the location and size of Head of Stone's many buildings and architectural patterns, which are typical of Maya sites: 70-foot-tall "triadic pyramid," an astronomical observatory, a ritual ball court, numerous plazas and also residential mounds that would have been the homes of elites and commoners, according to archaeologist Brigitte Kovacevich, Southern Methodist University, Dallas.


The map situates the primary buildings relative to one another and also places them within the context of the site's hills and valleys in the Central Lakes agricultural region of north-central Guatemala.


The buildings date from 800 B.C. to 900 A.D., says Kovacevich, an expert in Meso-American cultures and co-leader of an international scientific team that has been granted permission by the Guatemalan government to work the site, which has never before been excavated.


Movement to understand early periods, how kingship developed


Known for its far-reaching state-level government, Maya civilization during the "Classic" period from 200 A.D. to 900 A.D. consisted of huge monumental cities with tens of thousands of people ruled by powerful kings, palaces, pyramidal temples and complex political and economic alliances, Kovacevich says.


The ancient culture at its peak during the Classic period has been well-documented by archaeologists studying the civilization's large urban centers, such as Tikal, which was one of the most powerful and long-lasting of the Maya kingdoms.


In contrast, "Head of Stone," called "Holtun" in Maya, is a modest site from the "Pre-Classic" period, 600 B.C. to 250 A.D., she says. The small city had no more than 2,000 people at its peak. Situated about 35 kilometers south of Tikal, "Head of Stone" in its heyday preceded the celebrated vast city-states and kingship culture for which the Maya are known.


By excavating a small city, Kovacevich says, the archaeologists hope to understand early Maya trade routes and alliances, the importance of ritual for developing political power, how political power emerged, and how kingship lines evolved and solidified.


"There is a movement toward a greater understanding of these early periods, with smaller sites and common people," says Kovacevich, an assistant professor in SMU's Anthropology Department. "Little is known about how kingship developed, how individuals grabbed political power within the society, how the state-level society evolved and why it then was followed by a mini-collapse between 100 A.D. and 250 A.D."


Kovacevich presented "'Head of Stone': Archaeological Investigation at the Maya Site of Holtun, Guatemala" during the 76th annual meeting of the Society for American Archaeology in Sacramento, Calif., March 30 to April 3.


Besides Kovacevich, archaeologists on the team and co-authors of the paper are Michael G. Callaghan, University of Texas at Arlington; Patricia R. Castillo, Universidad San Carlos, Guatemala; and Rodrigo Guzman, Universidad del Valle, Guatemala. The 3-D topographic map expands surveys from 1995 and 2002 by Guatemalan archaeologist Vilma Fialko and Guatemala's Institute of Anthropology and History, which were documented by Fialko and archaeologist Erick M. Ponciano.


Situated in a patch of rainforest on defensible escarpment


Head of Stone today sits in a patch of rainforest surrounded by cow pastures and cornfields on a limestone escarpment, which would have made it highly defensible, Kovacevich says.


Holtun's structures — more than 100 of them — now are overgrown with a thin layer of centuries-old jungle foliage and soil. The site is about one kilometer long and half a kilometer wide, or almost three-quarters of a mile long and one-third of a mile wide. The large mounds protruding here and there from the jungle floor signal to archaeologists the familiar building arrangements customary at a Maya site, Kovacevich says.


As with most Maya sites, looters have tunneled into many of the important structures. Kovacevich and her colleagues will dig more tunnels to further explore the buildings with the help of Guatemalan experts skilled at working Maya sites.


Key structures: "E Group," residential group


The 3-D mapping has confirmed an "E Group," a key Maya architectural structure. Holtun's "E Group" dates from 600 B.C. to 600 A.D. and consists of stair-step pyramids and elongated buildings that likely served as astronomical observatories central to Maya rituals. A stepped pyramid to the west of a long narrow building directly oriented north-south served as the observational structure and was related to veneration of sacred ancestors, Kovacevich says.


"From the observational structure you can see the sun rising at the different solstices throughout the year, which is very important agriculturally, to know the timing of the seasons and when to plant and when to harvest," she says. "So the people creating this are harnessing that knowledge to show their followers and constituents that they possibly are even controlling the change of seasons."


Adjacent to the "E Group" are four structures that face one another around a central patio. The pattern usually indicates a residential group, where cooking and food processing were carried out on the patio, Kovacevich says.


"The closeness of the residential structure to the "E Group" suggests these were very early elites, and possibly kings," she says. "Kingship was just being established during this period."


The Maya often left offerings to their ancestors, such as jade or ceramics, at the base of structures.


Triadic pyramid represents Maya mythology?


Besides the "E Group," a triadic pyramid dating from 300 B.C. to 300 A.D. sits at the north end of the site. As is typical at Maya sites, three pyramids about 10 feet tall sit atop a high platform that rises about 60 feet from the jungle floor, Kovacevich says. One of the pyramids faces south, flanked on either side by the other two, which face inward around a central patio. The platform sits atop — and obscures — an earlier sub-structure platform, buried underground and decorated with monumental masks that are visible from the looters' tunnels.


"Some archaeologists argue that this configuration represents elements of Maya mythology: the three hearthstones of creation that were set down by the gods to create the first home and hearth, thereby civilizing humanity," Kovacevich says. "Re-creation of that by the people at Holtun would show piousness and connection to ancestors."


During the Classic period, kings were typically buried in Maya pyramids. During the Pre-Classic period, however, that isn't the case and they were typically buried in their residence. It's possible an early king of Holtun was buried in one of the residential structures, Kovacevich says.


"Ancestors are buried beneath the floor and kept very close and venerated," she says. "The more ancestors a residence has, the more times the family redoes their floor, making a new floor, and so their mound gets higher and higher. A person with more ties, more ancestors, has more status."


Another familiar structure is a ball court, signified by two long mounds that are exactly parallel, said Kovacevich.


"Those are the two sides of the ball court, and the ball would have been bounced in the center off of the sides," she said. "Almost all Maya sites had a ball court."


The team's Holtun excavation is scheduled to start this summer. Funding is from the Institute for the Study of Earth and Man, the Downey Family Fund for Faculty Excellence and SMU. — Margaret Allen


Source : smu.edu
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