Wednesday, July 2, 2008

Archaeologists Find Silos And Administration Center From Early Egyptian City

ScienceDaily (July 2, 2008) — A University of Chicago expedition at Tell Edfu in southern Egypt has unearthed a large administration building and silos that provide fresh clues about the emergence of urban life. The discovery provides new information about a little understood aspect of ancient Egypt—the development of cities in a culture that is largely famous for its monumental architecture.
The archaeological work at Tell Edfu was initiated with the permission of the Supreme Council of Antiquities, headed by Zahi Hawass, under the direction of Nadine Moeller, Assistant Professor at the Oriental Institute, University of Chicago. Work late last year revealed details of seven silos, the largest grain bins found in ancient Egypt as well as an older columned hall that was an administration center.
Long fascinated with temples and monuments such as pyramids, scholars have traditionally spent little time exploring the residential communities of ancient Egypt. Due to intense farming and heavy settlement over the years, much of the record of urban civilization has been lost. So little archaeological evidence remains that some scholars believe Egypt did not have a highly developed urban culture, giving Mesopotamia the distinction of teaching people how to live in cities.
"The traditional view of ancient Egypt has been biased by the fact that most excavation work so far has focused on temples and tombs. The mounds which comprise the remains of Egyptian cities were either ignored, buried under modern towns, or else destroyed by modern agricultural activities. Edfu is one of the very few remaining city mounds that are accessible for scientific study," said Gil Stein, Director of the Oriental Institute.
"The work at Edfu is important and innovative in that it finally allows us to examine ancient Egypt as an urban society, whose cities and towns housed bureaucrats, craft specialists, priests, and farmers. Nadine Moeller's discovery of silos and local administrative buildings shows us how these cities actually functioned as places where the agricultural wealth of the Nile valley was mobilized for the state. Grain as currency provided the sinews of power for the pharoahs," he added.
"Ancient Egyptian administration is mainly known from texts, but the full understanding of the institutions involved and their role within towns and cities has been so far difficult to grasp because of the lack of archaeological evidence with which textual data needs to be combined," Moeller said.
At Tell Edfu, archaeologists have uncovered what amounts to a downtown area. The community, halfway between the modern cities of Aswan and Luxor, was a provincial capital an important regional center. Tell Edfu is also rare, in that almost 3,000 years of Egyptian history are preserved in the stratigraphy of a single mound.
The administrative building and silos were at the heart of the ancient community. Because grain was a form of currency, the silos functioned as a bank and a food source. The silos' size indicates the community was apparently a prosperous urban center.
The grain bins are in a large silo courtyard of the 17th Dynasty (1630-1520 B.C.) and consist of at least seven round, mud-brick silos. With a diameter between 5.5 and 6.5 meters, they are the largest examples discovered within a town center.
The team unearthed an earlier building phase for the hall that predated the silos. In that phase, a mud-brick building with 16 wooden columns stood at the site. The pottery and seal impressions found in the hall date it to the early 13th Dynasty (1773-1650 B.C.). The building layout indicates that it may have been part of the governor's palace, which was typical of provincial towns.
There is no exact parallel for such a columned hall being part of the administrative buildings. Scribes did accounting, opened and sealed containers, and received letters in the column hall. The ostraca, or inscribed pottery shards, list commodities written on them.
The administrative center was used when Egypt's political unity was lost and a small kingdom developed at Thebes (modern Luxor) and controlled most of Upper Egypt.
"During this period, we can see an increase in connections between the provincial elite, such as the family of the governor, to the royal family at Thebes, who were keen on strengthening bonds through marriage, or by awarding important offices to these people," Moeller said.
"It is exactly at this period when Edfu seems to have been very prosperous, which can now be confirmed further by archaeological discoveries such as this silo-court, a symbol for the wealth of the town," she said.

Newcomer In Early Eurafrican Population?

ScienceDaily (July 2, 2008) — A complete mandible of Homo erectus was discovered at the Thomas I quarry in Casablanca by a French-Moroccan team co-led by Jean-Paul Raynal, CNRS senior researcher at the PACEA laboratory (CNRS/Université Bordeaux 1/ Ministry of Culture and Communication). This mandible is the oldest human fossil uncovered from scientific excavations in Morocco. The discovery will help better define northern Africa's possible role in first populating southern Europe.
A Homo erectus half-jaw had already been found at the Thomas I quarry in 1969, but it was a chance discovery and therefore with no archeological context. This is not the case for the fossil discovered May 15, 2008, whose characteristics are very similar to those of the half-jaw found in 1969.
The morphology of these remains is different from the three mandibles found at the Tighenif site in Algeria that were used, in 1963, to define the North African variety of Homo erectus, known as Homo mauritanicus, dated to 700,000 B.C.
The mandible from the Thomas I quarry was found in a layer below one where the team has previously found four human teeth (three premolars and one incisor) from Homo erectus, one of which was dated to 500,000 B.C. The human remains were grouped with carved stone tools characteristic of the Acheulian civilization and numerous animal remains (baboons, gazelles, equines, bears, rhinoceroses, and elephants), as well as large numbers of small mammals, which point to a slightly older time frame. Several dating methods are being used to refine the chronology.
The Thomas I quarry in Casablanca confirms its role as one of the most important prehistoric sites for understanding the early population of northwest Africa. The excavations that CNRS and the Institut National des Sciences de l'Archéologie et du Patrimoine du Maroc have led there since 1988 are part of a French-Moroccan collaboration. They have been jointly financed by the French Ministry of Foreign Affairs, the Department of Human Evolution at the Max Plank Institute in Leipzig (Germany), INSAP (Morocco) and the Aquitaine region.

Sunday, May 25, 2008

Crystal Skulls' Murky Tale

An 'Aztec' Artifact Is As Fictional As Indiana Jones
Write to Christina Passariello at

PARIS -- Ever since the Quai Branly Museum placed its crystal skull in a glass display case a week ago, visitors have been swarming around the spooky artifact.
The museum's directors brought it out of storage to coincide with the release of the movie "Indiana Jones and the Kingdom of the Crystal Skull," opening this weekend. The film's plot is loosely based on the legend that 13 crystal skulls, dating from the Aztec period more than 500 years ago, must be reunited by 2012 to prevent the end of the world
But the Quai Branly's skull, along with others in prestigious museums such as the Smithsonian Institution and the British Museum, are all phonies. The museum concedes that it knows little about the skull. Explanatory text next to the skull's display case doesn't explain much: "19th century? Europe?"
The bigger question: Why is a museum promoting an artifact it knows isn't authentic?
Partly because the public doesn't really care, notes Esther Pasztory, an art-history professor at Columbia University. "People want to see Aztec art," she notes, even if it isn't really Aztec art. Museums should clearly disclose counterfeit artifacts, she says, adding that known fakes still have their fans.
Fakes were once a source of embarrassment for museums. But more recently, they have become objects of fascination. In 1990, the British Museum put its most famous examples on display, including a sarcophagus that once was thought to be from the sixth century but was actually made in the 19th century.
Some fakes grow so notorious that they have taken on a significance of their own, becoming part of counterfeit lore. In 1896, the Louvre was duped into buying a rare gold tiara that it believed was a Greek treasure from the third century B.C. A German archaeologist soon proved it was a forgery, made by a Russian craftsman only a few years before it was sold. Humiliated by the affair, the Louvre locked it away for decades until the museum allowed the Israel Museum in Jerusalem to feature the tiara in a 1997 exhibition on the Russian craftsman.
"The crystal skulls are legitimate artifacts, just not what they purport to be," says Jane Walsh, an anthropologist at the Smithsonian's National Museum of Natural History, who has studied 10 skulls since the Smithsonian received one as an anonymous donation in 1992. "We have to think of a new way of describing them. It's hard to call them fakes; sometimes I call them inventions," she says.
Museums are full of imitations, experts say. More than 600 were shown at the British Museum's exhibition. Many museum fakes were acquired during the rush to create large national collections in the late 19th century. "All museums have extraordinary fakes," says Stéphane Martin, the president of the Quai Branly, which opened two years ago to house France's national African, American, Asian and Oceanic collections.
Mr. Martin recalls being awed by the crystal skull as a boy when it was housed at Paris's Musée de l'Homme. But it wasn't until decades later, when preparing for the Quai Branly's opening, that he learned that the skull's Aztec origin was concocted. The British Museum and the Smithsonian shared the research they had done on their respective skulls. In the 1990s, Ms. Walsh of the Smithsonian had pored over excavation documents from pre-Columbian digs. No one had ever claimed to unearth a crystal skull.
Technological advances, which are unearthing previously undetected fakes, also let experts at the British Museum to go further in their study. In 1996, they analyzed the way holes were bored into the rock crystal for eyes, and into the top of the head. These were far too precise to have been done by hand. Using high-powered microscopes and scanners, the researchers concluded the tool marks left on the British and American skulls came from rotary machines. The Aztecs didn't possess such drills.
The British Museum informed Mr. Martin that it thought the French skull also wasn't genuine: Both the British and the French skulls had passed through the hands of a disreputable French antiquarian from the late 1800s, Eugène Boban. He peddled crystal skulls said to be from Mexico, beginning in the 1860s. Experts say he was well aware of their fraudulent origins -- and helped stoke the apocalyptic legend that surrounds them today.
Skulls -- carved out of volcanic rock -- were used in Aztec culture to commemorate human sacrifice. By claiming the crystal skulls were Aztec, which at the time conferred a mystical aura, Mr. Boban cloaked them in enigma. The myth of their significance snowballed for a century.
Mr. Martin decided not to include the French skull in the Quai Branly's permanent display because of space constraints. But the crystal sculpture had already attracted groups of fans and believers. He says he received letters from disgruntled devotees accusing him of not showing the skull out of fear of its curse. That's when he realized there was strong interest in the skull -- despite its dubious origins.
Over the past year, French researchers conducted a new investigation into the skull and reached the same conclusion as the British Museum and the Smithsonian. "Its story is strange and people like to talk about it," he says.
When Mr. Martin learned the title of the new Indiana Jones movie, he saw the opportunity to wheel the crystal skull out of storage. He doesn't deny that he thought the skull would drive visitors to the museum, despite its fake provenance. "We're riding a pop-culture wave, and we're trying to exploit it to our advantage," says Mr. Martin.
"But of course it's fake," said Yvane Hardy Riotte, a tattooed visitor who had come to see the skull. "The real ones are so powerful that no museum would dare to bring them out."
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Wednesday, May 21, 2008

First Dinosaur Tracks Discovered On Arabian Peninsula

ScienceDaily (May 21, 2008) — Scientists have discovered the first dinosaur tracks on the Arabian Peninsula. They have discovered evidence of a large ornithopod dinosaur, as well as a herd of 11 sauropods walking along a Mesozoic coastal mudflat in what is now the Republic of Yemen.
"No dinosaur trackways had been found in this area previously. It's really a blank spot on the map," said Anne Schulp of the Maastricht Museum of Natural History in The Netherlands. He conducted the study with Ohio University paleontologist Nancy Stevens and Mohammed Al-Wosabi of Sana'a University in Yemen.
The finding also is an excellent example of dinosaur herding behavior, the researchers report. The site preserved footprints of 11 small and large sauropods -- long-necked, herbivorous dinosaurs that lived in the Jurassic and Cretaceous periods -- traveling together at the same speed.
"It's rare to see such a big example of a dinosaur herd," Schulp said. "This is interesting social behavior for reptiles."
A Yemeni journalist spotted one of the trackways in 2003, about 50 kilometers north of the capital of Sana'a in the village of Madar. Stevens, Al-Wosabi and Schulp identified it as the footprint of an ornithopod, a large, common plant-eater sometimes referred to as the "cow of the Mesozoic," Schulp said. It walked on its hind legs.
Only a few dinosaur fossils have been reported so far from the Arabian Peninsula, including isolated bones from the Sultanate of Oman, which Schulp has studied, and possible fragments of a long-necked dinosaur from Yemen.
In late 2006, the research team conducted further field work at the Madar site. By taking measurements on the shape and angle of the different digits, they were able to identify the bipedal dinosaur as an ornithopod. The size, shape and spacing of the quadrupedal prints were used to identify the body size, travel speed and other distinguishing features of the animals in the sauropod herd, Stevens said.
The rocks in which the dinosaur tracks are preserved are likely Late Jurassic in age, some 150 million years old, according to Al-Wosabi. The tracks probably went unnoticed for so long, Schulp explained, because they were too big to be spotted by the untrained eye and were partially covered by rubble and debris. "It isn't a surprise that they were overlooked," he said.
Though ornithopods and sauropods overlapped in time, it's a bit unusual to find evidence of such a big ornithopod in the late Jurassic, the researchers noted.
"We really want to learn when did which dinosaurs live where, and why was that?" Schulp said. "How did the distribution change over time, why did one replace another and move from one place to another?"
The researchers agreed that discoveries from Yemen could yield more answers to those questions.
"This international collaboration provides an exciting new window into evolutionary history from a critically undersampled region," said Stevens, an assistant professor in Ohio University's College of Osteopathic Medicine. "These trackways help us to assemble a more detailed picture of what was happening on the southern landmasses. It's exciting to see new paleontological data coming out of Yemen -- and I think there is a lot more to discover."
The Yemen Geological Survey has implemented protective measures to preserve the trackways and to improve their accessibility to tourists, the researchers report.
Partial funding for the research was provided by the Yemen Geological Survey and Ohio University.
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Wednesday, May 7, 2008

Dinosaur Bones Reveal Ancient Bug Bites

ScienceDaily (May 6, 2008) — Paleontologists have long been perplexed by dinosaur fossils with missing pieces – sets of teeth without a jaw bone, bones that are pitted and grooved, even bones that are half gone. Now a Brigham Young University study identifies a culprit: ancient insects that munched on dinosaur bones.
BYU professor Brooks Britt will publish his study of these dinosaur bone-eating bugs in the May 8 issue of the scientific journal Ichnos. Britt’s idea for this study came when he first noticed the unique markings on the bones as an undergraduate at BYU.
“As students we noticed these marks and thought it might be due to algae or insects and we started calling them ‘bug bites,’ just for fun,” Britt said.
Years later, current BYU student Anne Dangerfield also wondered about the markings and teamed up with Britt to investigate the cause. They studied insect traces on the 148-million-year-old remains of a Camptosaurus, a plant-eating specimen discovered in Medicine Bow, Wyo., in 1995.
“I knew this trace was something different because I had been looking at fossil termite traces all summer, so I knew we needed to check it out,” Dangerfield said.
Their analysis revealed that beetles, from the family entomologists call Dermestidae, left the markings on the Camptosaurus. Dermestid beetles still exist today and are typically brown or black, oval-shaped and feed on flesh, hair, skin or horns of carcasses.
Information about the beetle’s typical habitat reveals the climate at the time of the Camptosaurus’ death probably had 60-80 percent relative humidity and a temperature of 77-86 F. By comparison, the average yearly temperature in Medicine Bow is now 43.5 F.
When the dinosaur died near what is now Medicine Bow, the carcass was consumed by other insects. The beetles then infested the Camptosaurus within months of its death.
In addition to shedding light on Wyoming’s ancient climate, Dangerfield and Britt’s work shows dermestid beetles existed much earlier than previously thought. The traces on this Camptosaurus predate the oldest body fossils for dermestid beetles by 48 million years.
“This information gives us an idea of the environment during the Jurassic period and the evolution of insects,” Dangerfield said.
To analyze the markings on the bones, Britt went to his family dentist for molding materials, allowing Britt to more quickly create replicas of the bone traces to work with.
He took the castings back to BYU’s Earth Science Museum where he used an electron microscope to look at the mandible markings in the bone, analyzing eating patterns and the width between the teeth marks. Britt and Dangerfield compared the marks to information about the mandibles of moths, termites, mayflies and dermestid beetles – all known to consume bone – to determine the identity of the insect.
“Other people have thought they have seen dermestid beetle marks, or they have interpreted termite marks as dermestids, but this paper provides a guide to identifying insects from the bone traces,” Britt said.
Britt and Dangerfield continued their research by looking at more than 7,000 bones from various quarries and found that insect traces on dinosaur bones are quite common, but dermestid beetle traces were found only on the Camptosaurus skeleton from Medicine Bow.
“Dr. Britt’s work is really exciting and delves into unique aspects of paleobiology that few scientists have yet explored,” said Eric Roberts, an expert in dinosaur decomposition who teaches at South Africa’s University of the Witwatersrand. “Insects are among the most diverse and abundant organisms on the planet, yet we know next to nothing about the fossil record of insects because of their extremely limited preservation potential.”
Dangerfield’s undergraduate and graduate mentored research experience has impressed many potential employers. After finishing her master’s degree in August, she will assume a position with Exxon Mobile as an exploration oil and gas geologist.
“Whenever I show my resume, employers are impressed with the amount of undergraduate research I’ve done,” Dangerfield said.
Britt received his bachelor’s and master’s degrees at BYU and his Ph.D. at the University of Calgary and is an assistant professor. Rodney Scheetz, another author on the study, is the curator at BYU’s Earth Science Museum.
Adapted from materials provided by Brigham Young University.
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Monday, April 28, 2008

When Did Dinosaurs Go Extinct? Cretaceous-Tertiary Boundary Dating Refined

ScienceDaily (Apr. 28, 2008) — Scientists at the University of California, Berkeley, and the Berkeley Geochronology Center have pinpointed the date of the dinosaurs' extinction more precisely than ever thanks to refinements to a common technique for dating rocks and fossils.
The argon-argon dating method has been widely used to determine the age of rocks, whether they're thousands or billions of years old. Nevertheless, the technique had systematic errors that produced dates with uncertainties of about 2.5 percent, according to Paul Renne, director of the Berkeley Geochronology Center and an adjunct professor of earth and planetary science at UC Berkeley.
Renne and his colleagues in Berkeley and in the Netherlands now have lowered this uncertainty to 0.25 percent and brought it into agreement with other isotopic methods of dating rocks, such as uranium/lead dating. As a result, argon-argon dating today can provide more precise absolute dates for many geologic events, ranging from volcanic eruptions and earthquakes to the extinction of the dinosaurs and many other creatures at the end of the Cretaceous period and the beginning of the Tertiary period. That boundary had previously been dated at 65.5 million years ago, give or take 300,000 years.
According to a paper by Renne's team in the April 25 issue of Science, the best date for the Cretaceous-Tertiary, or K/T, boundary is now 65.95 million years, give or take 40,000 years.
"The importance of the argon-argon technique is that it is the only technique that has the dynamic range to cover nearly all of Earth's history," Renne said. "What this refinement means is that you can use different chronometers now and get the same answer, whereas, that wasn't true before."
Renne noted that the greater precision matters little for recent events, such as the emergence of human ancestors in Africa 6 million years ago, because the uncertainty is only a few tens of thousands of years.
"Where it really adds up is in dating events in the early solar system," Renne said. "A 1 percent difference at 4.5 billion years is almost 50 million years."
One major implication of the revision involves the formation of meteorites, planetessimals and planets in the early solar system, he said. Argon-argon dating was giving a lower date than other methods for the formation of meteorites, suggesting that they cooled slowly during the solar system's infancy.
"The new result implies that many of these meteorites cooled very, very quickly, which is consistent with what is known or suggested from other studies using other isotopic systems," he said. "The evolution of the early solar system - the accretion of planetessimals, the differentiation of bodies by gravity while still hot - happened very fast. Argon-argon dating is now no longer at odds with that evidence, but is very consistent with it."
Renne has warned geologists for a decade of uncertainty in the argon-argon method and has been correcting his own data since 2000, but it took a collaboration that he initiated in 1998 with Jan R. Wijbrans of the Free University in the Netherlands to obtain convincing evidence. Wijbrans and his Dutch colleagues were studying a unique series of sediments from the Messinian Melilla-Nador Basin on the coast of Morocco that contain records of cycles in Earth's climate that reflect changes in Earth's orbit that can be precisely calculated.
Wijbrans' colleague Frits Hilgen at the University of Utrecht, a coauthor of the study, has been one of the world's leaders in translating the record of orbital cycles into a time scale for geologists, according to Renne. Renne's group had proposed using the astronomical tuning approach to calibrate the argon-argon method as early as 1994, but lacked ideal sedimentary sequences to realize the full power of this approach. The collaboration brought together all the appropriate expertise to bring this approach to fruition, he said.
"The problem with astronomical dating of much older sediments, even when they contain clear records of astronomical cycles, is that you're talking about a pattern that is not anchored anywhere," Renne said. "You see a bunch of repetitions of features in sediments, but you don't know where to start counting."
Argon-argon dating of volcanic ash, or tephra, in these sediments provided that anchor, he said, synchronizing the methods and making each one more precise. The argon-argon analyses were conducted both in Berkeley and Amsterdam to eliminate interlaboratory bias.
Argon-argon dating, developed at UC Berkeley in the 1960s, is based on the fact that the naturally-occurring isotope potassium-40 decays to argon-40 with a 1.25-billion-year half-life. Single-grain rock samples are irradiated with neutrons to convert potassium-40 to argon-39, which is normally not present in nature. The ratio of argon-39 to argon-39 then provides a measurement of the age of the sample.
"This should be the last big revision of argon-argon dating," Renne said. "We've finally narrowed it down to where we are talking about fractions-of-a-percent revisions in the future, at most."
Klaudia Kuiper, the lead author of the Science paper, was a Ph.D. student in Amsterdam working with study coauthors Wijbrans, Hilgen and Wout Krijgsman when the study was initiated. She also conducted lab work with Renne and Alan Deino, a geochronologist with Renne at the Berkeley Geochronology Center who was also one of the study's coauthors.
The work was funded by the U.S. and Dutch National Science Foundations and the Ann and Gordon Getty Foundation.
Adapted from materials provided by University of California - Berkeley.
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Friday, April 25, 2008

Molecular Analysis Confirms Tyrannosaurus Rex's Evolutionary Link To Birds

ScienceDaily (Apr. 25, 2008) — Putting more meat on the theory that dinosaurs' closest living relatives are modern-day birds, molecular analysis of a shred of 68-million-year-old Tyrannosaurus rex protein -- along with that of 21 modern species -- confirms that dinosaurs share common ancestry with chickens, ostriches, and to a lesser extent, alligators.
The work, published in the journal Science, represents the first use of molecular data to place a non-avian dinosaur in a phylogenetic tree that traces the evolution of species. The scientists also report that similar analysis of 160,000- to 600,000-year-old collagen protein sequences derived from mastodon bone establishes a close phylogenetic relationship between that extinct species and modern elephants.
"These results match predictions made from skeletal anatomy, providing the first molecular evidence for the evolutionary relationships of a non-avian dinosaur," says co-author Chris Organ, a postdoctoral researcher in organismic and evolutionary biology at Harvard University. "Even though we only had six peptides -- just 89 amino acids -- from T. rex, we were able to establish these relationships with a relatively high degree of support. With more data, we'd likely see the T. rex branch on the phylogenetic tree between alligators and chickens and ostriches, though we can't resolve this position with currently available data."
The current paper builds on work reported in Science last year. In that paper, a team headed by John M. Asara and Lewis C. Cantley, both of Beth Israel Deaconess Medi-cal Center (BIDMC) and Harvard Medical School (HMS), first captured and sequenced tiny pieces of collagen protein from T. rex. For the current work, Organ and Asara and their colleagues used sophisticated algorithms to compare collagen protein from several dozen species. The goal: placing T. rex on the animal kingdom's family tree using molecu-lar evidence.
"Most of the collagen sequence was obtained from protein and genome databases but we also needed to sequence some critical organisms, including modern alligator and modern ostrich, by mass spectrometry," says Asara, director of the mass spectrometry core facility at BIDMC and instructor in pathology at HMS. "We determined that T. rex, in fact, grouped with birds -- ostrich and chicken -- better than any other organism that we studied. We also show that it groups better with birds than modern reptiles, such as alliga-tors and green anole lizards."
While scientists have long suspected that birds, and not more basal reptiles, are di-nosaurs' closest living relatives, for years that hypothesis rested largely on morphological similarities in bird and dinosaur skeletons.
The scraps of dinosaur protein were wrested from a fossil femur discovered in 2003 by John Horner of the Museum of the Rockies in a barren fossil-rich stretch of land that spans Wyoming and Montana. Mary H. Schweitzer of North Carolina State Univer-sity (NCSU) and the North Carolina Museum of Natural Sciences discovered soft-tissue preservation in the T. rex bone in 2005; Asara became involved in analysis of the colla-gen protein because of his expertise in mass spectrometry techniques capable of se-quencing minute amounts of protein from human tumors. While it appears impossible to salvage DNA from the bone, Asara was able to extract precious slivers of protein.
The current work by Organ and Asara suggests that the extracted protein from the fossilized dinosaur tissue is authentic, rather than contamination from a living spe-cies.
"These results support the endogenous origin of the preserved collagen mole-cules," the researchers write.
Organ, Asara, Schweitzer, and Cantley's co-authors on the Science paper are Wenxia Zheng of NCSU and Lisa M. Freimark of BIDMC. Their research was funded by the National Institutes of Health, the National Science Foundation, the Paul F. Glenn Foundation, and the David and Lucile Packard Foundation.
Adapted from materials provided by Harvard University.

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Sunday, April 20, 2008

Early Elephant 'Was Amphibious'


ScienceDaily (Apr. 20, 2008) — The scientists were investigating the lifestyle of two early elephants (proboscideans) Moeritherium and Barytherium that lived in the Eocene period, over 37 million years ago. By analysing isotopes in tooth enamel from Moeritherium they were able to deduce that it was very likely a semi-aquatic mammal, spending its days in water eating freshwater plants.‘
We know from molecular data that modern elephants share a common ancestry with the sirenians - aquatic sea cows and dugongs,’ said Alexander Liu of Oxford’s Department of Earth Sciences, lead author of a report of the research published online in PNAS. ‘It suggests that elephants may have an ancestor which was amphibious in its mode of life and we wanted to know if Moeritherium or Barytherium was this semi-aquatic ancient relative. Unfortunately only fragments of the skeletons of these early elephants survive, so instead of looking at their bones we looked at the chemical composition of their teeth to determine what they ate and how they lived.’
Alex Liu, with colleagues Erik Seiffert from Stony Brook University (USA) and Elwyn Simons from the Duke Lemur Center (USA), analysed the oxygen and carbon isotope ratios contained within tooth enamel from both extinct proboscideans.
While carbon isotopes can give clues as to an animal’s diet, oxygen isotopes found in teeth come from local water sources - and variations in the ratios of these isotopes can indicate the type of environment the animal lived in. They compared the ratios of these isotopes to definitely terrestrial animals from the same period and these results – when combined with results from studies of embryology, molecular data, and sedimentology – lead them to believe that Moeritherium was semi-aquatic.
Alex Liu commented: ‘We now have substantial evidence to suggest that modern elephants do have ancient relatives which lived primarily in water. The next steps are to conduct similar analyses on other elephant ancestors to determine when the switch from water to land occurred, and to determine exactly when the now fully-aquatic sirenians split from their semi-aquatic proboscidean relatives.’
Adapted from materials provided by University Of Oxford.

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Sunday, March 23, 2008

Upright Walking Began 6 Million Years Ago, Thigh Bone Comparison Suggests

ScienceDaily (Mar. 21, 2008) — A shape comparison of the most complete fossil femur (thigh bone) of one of the earliest known pre-humans, or hominins, with the femora of living apes, modern humans and other fossils, indicates the earliest form of bipedalism occurred at least six million years ago and persisted for at least four million years. William Jungers, Ph.D., of Stony Brook University, and Brian Richmond, Ph.D., of George Washington University, say their finding indicates that the fossil belongs to very early human ancestors, and that upright walking is one of the first human characteristics to appear in our lineage, right after the split between human and chimpanzee lineages. Their findings are published in the March 21 issue of the journal Science.
The research is the first thorough quantitative analysis of the Orrorin tugenensis fossil – a fragmentary piece of femur – which was discovered in Kenya in 2000 by a French research team. Dr. Jungers, Chair of Anatomical Sciences at SBU School of Medicine, and Dr. Richmond, Associate Professor of Anthropology at GWU and a member of GWU’s Center for the Advanced Study of Hominid Paleobiology, completed a multivariate analysis of the proximal femora shape of a young adult O. tugenensis that enabled them to pinpoint the pattern of bipedal gait for this controversial hominin. Their analysis included a large and diverse sample of apes, other early hominins, including Australopithecus, and modern humans of all body sizes.
“This research solidifies the evidence that the human lineage split off as far back as six million years ago, that we share ancestry with Orrorin, and that our ancestors were walking upright at the time,” says Dr. Richmond. “These answers were not clear before this analysis.”
“Our study confirms that as early as six million years ago, basal hominins in Africa were already similar to later australopithecines in their anatomy and inferred locomotor biomechanics,” adds Dr. Jungers. “At the same time, by way of the analysis, we see no special phylogenetic connection between Orrorin and our own genus, Homo.”
In “Orrorin tugenensis Femoral Morphology and the Evolution of Hominin Bipedalism,” the authors articulate that the analysis and morphological comparisons among femora from the fossils showed that O. tugenensis is distinct from those of modern humans and the great apes in having a long, anteroposteriorly narrow neck and wide proximal shaft. Early Homo femora have larger heads and broader necks compared to early hominins. In addition to these features, modern human femora have short necks and mediolaterally narrow shafts.
The challenge ahead, explains Dr. Jungers, is “to identify what precipitated the change from this ancient and successful adaptation of upright walking, and climbing, to our own obligate form of bipedalism.”
Adapted from materials provided by Stony Brook University Medical Center.

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Ancient Lemur's Little Finger Poses Mystery

ScienceDaily (Mar. 22, 2008) — Analysis of the first hand bones belonging to an ancient lemur has revealed a mysterious joint structure that has scientists puzzled.
Pierre Lemelin, an assistant professor of anatomy at the University of Alberta in Edmonton, Canada, and a team of fellow American researchers have analyzed the first hand bones ever found of Hadropithecus stenognathus, a lemur that lived 2,000 years ago.
The bones were discovered in 2003 in a cave in southeastern Madagascar, an island nation off the coast of Africa in the Indian Ocean. Hadropithecus is related to the modern-day sifaka, a type of lemur with acrobatic leaping skills. A lemur is a monkey-like animal with a long tail and large eyes.
An examination of the five tiny hand bones by Lemelin and the rest of the research team revealed a never-before-seen hand joint configuration on the side of the little finger. The same joint configuration is straight in all other primates, including Archaeolemur, a close extinct relative of Hadropithecus.
"Our analysis showed a mosaic of lemurid-like, monkey-like and very unique morphological traits," Lemelin said. "Because the joint was present on both hands, it's likely not an anomaly, but because there are no other Hadropithecus hand bones for comparison, we don't know for certain," Lemelin said. "It is a mystery, and further investigation is needed to explain the difference in this species."
Lemelin and his colleagues from George Washington University, the Medical College of Georgia, and the universities of Stony Brook and Massachusetts at Amherst, also discovered that, unlike its close living relatives, Hadropithecus lacked anatomical traits linked with wrist mobility and strong finger flexion that characterize primate species that climb or cling to trees.
The hand bones also showed that Hadropithecus had very short thumbs and was a quadrupedal species, walking on all fours, much like many primates, such as baboons, do today. The discovery underscores the amazing diversity of lemurs that existed more than 2,000 years ago, when lemurs of all types ranged from pocket-sized to the size of gorillas, Lemelin noted.
The findings were published this month in the Journal of Human Evolution.
The study was funded by the Natural Sciences and Engineering Research Council of Canada and The Leakey Foundation.
Adapted from materials provided by University of Alberta, via EurekAlert!, a service of AAAS.

Fausto Intilla

New Zealand's 'Living Dinosaur' -- The Tuatara -- Is Surprisingly The Fastest Evolving Animal

ScienceDaily (Mar. 23, 2008) — In a study of New Zealand's "living dinosaur" the tuatara, evolutionary biologist, and ancient DNA expert, Professor David Lambert and his team from the Allan Wilson Centre for Molecular Ecology and Evolution recovered DNA sequences from the bones of ancient tuatara, which are up to 8000 years old. They found that, although tuatara have remained largely physically unchanged over very long periods of evolution, they are evolving - at a DNA level - faster than any other animal yet examined.
"What we found is that the tuatara has the highest molecular evolutionary rate that anyone has measured," Professor Lambert says.
The rate of evolution for Adélie penguins, which Professor Lambert and his team have studied in the Antarctic for many years, is slightly slower than that of the tuatara. The tuatara rate is significantly faster than for animals including the cave bear, lion, ox and horse.
"Of course we would have expected that the tuatara, which does everything slowly -- they grow slowly, reproduce slowly and have a very slow metabolism -- would have evolved slowly. In fact, at the DNA level, they evolve extremely quickly, which supports a hypothesis proposed by the evolutionary biologist Allan Wilson, who suggested that the rate of molecular evolution was uncoupled from the rate of morphological evolution."
Allan Wilson was a pioneer of molecular evolution. His ideas were controversial when introduced 40 years ago, but this new research supports them.
Professor Lambert says the finding will be helpful in terms of future study and conservation of the tuatara, and the team now hopes to extend the work to look at the evolution of other animal species.
"We want to go on and measure the rate of molecular evolution for humans, as well as doing more work with moa and Antarctic fish to see if rates of DNA change are uncoupled in these species. There are human mummies in the Andes and some very good samples in Siberia where we have some collaborators, so we are hopeful we will be able to measure the rate of human evolution in these animals too."
The tuatara, Sphendon punctatus, is found only in New Zealand and is the only surviving member of a distinct reptilian order Sphehodontia that lived alongside early dinosaurs and separated from other reptiles 200 million years ago in the Upper Triassic period.
Journal reference: Lambert et al.:"Rapid molecular evolution in a living fossil." Researchers include Jennifer M. Hay, Sankar Subramanian, Craig D. Millar, Elmira Mohandesan and David M. Lambert, Trends in Genetics. March 2008. (
Adapted from materials provided by Cell Press, via EurekAlert!, a service of AAAS.
Fausto Intilla

Good Luck Indeed: 53 Million-year-old Rabbit's Foot Bones Found

ScienceDaily (Mar. 24, 2008) — One day last spring, fossil hunter and anatomy professor Kenneth Rose, Ph.D. was displaying the bones of a jackrabbit's foot as part of a seminar at the Johns Hopkins University School of Medicine when something about the shape of the bones looked oddly familiar.
That unanticipated eureka moment has led researchers at the school to the discovery of the oldest known record of rabbits. The fossil evidence in hand, found in west-central India, predates the oldest previously known rabbits by several million years and extends the record of the whole category of the animal on the Indian subcontinent by 35 million years.
Published online in the February Proceedings of the Royal Society, the investigators say previous fossil and molecular data suggested that rabbits and hares diverged about 35 million years ago from pikas, a mousy looking member of the family Ochotonidae in the order of lagomorphs, which also includes all of the family Leporidae encompassing rabbits and hares.
But the team led by Johns Hopkins's Rose found that their rabbit bones were very similar in characteristics to previously unreported Chinese rabbit fossils that date to the Middle Eocene epoch, about 48 million years ago. The Indian fossils, dating from about 53 million years ago, appear to show advanced rabbit-like features, according to Rose.
"What we have suggests that diversification among the Lagamorpha group-all modern day hares, rabbits and pikas-may already have started by the Early Eocene," says Rose, professor in the Center for Functional Anatomy and Evolution at the Johns Hopkins University School of Medicine.
Rose says the new discovery was delayed a few years because the researchers had not been looking specifically to determine the age of rabbits. "We found these bones on a dig in India a few years ago and didn't know what animal they came from, so we held onto them and figured we'd look at them later," he says. "It didn't occur to us they would be rabbits because there were no known rabbits that early in time and the only known rabbits from that part of the world are from central Asia."
But one day, while using the jackrabbit foot bones as a teaching tool for a class, the shape of the bones in the class struck him as something he'd seen before among his collection of unidentified bones.
Sure enough, the tiny bones about a quarter of an inch long from India looked remarkably similar to ankle and foot bones from modern day jackrabbits, which are 4 to 5 times bigger.
Rose and his team set out and measured every dimension of their Indian bones and compared them to eight living species of rabbits and hares. They also compared them to two species of the related pika-that mouse-like, mountain-dwelling critter that lives in the Rocky Mountains of North America, among other places.
Using a technique called character analysis, the team first recorded measurements of 20 anatomical features of the bones, which showed that the bones are definitely Lagomorph and closer to rabbits than pikas. The scientists then ran a series of statistical tests on the individual measurements to see how they compared with the Chinese fossils as well as living rabbits and pikas. They found that although the Indian fossils resemble pikas in some primitive features, they look more like rabbits in specialized bone features.
Asked how many years of good luck one gets with a 53 million-year-old rabbit foot bone, Rose quipped that he "already got lucky with the feet, but what we really would like are some teeth that tell how different these animals really were."
The research was funded by the National Geographic Society, Department of Science and Technology, Government of India, the Council for Scientific and Industrial Research of India, the Research Foundation Flanders and the Belgian Federal Science Policy Office.
Authors on the paper are Valerie Burke DeLeon and Rose of Hopkins; Pieter Missiaen of University of Ghent, Belgium; R.S. Rana and Lachham Singh of H.N.B. Garhwal University in Uttaranchal, India; Ashok Sahni of Panjab University, India; and Thierry Smith of the Royal Belgian Institute of Natural Sciences in Brussels, Belgium.
Adapted from materials provided by Johns Hopkins Medical Institutions, via EurekAlert!, a service of AAAS.

Fausto Intilla