Bolivian farmer Primo Rivera had long wondered about the dents in a rocky hill near his home. Paleontologists solved the mystery this month: they are fossilized dinosaur footprints -- the oldest in Bolivia.

"I used to come to look at the prints when I was a kid ... but I didn't know what had made them," said Rivera, 35, who lives in the southern province of Chuquisaca.

The fossilized footsteps that intrigued Rivera for two decades are thought to be about 140 million years old, much older than other dinosaur prints found in the Andean country.

"The footprints we've found are important because they're the oldest ever found in Bolivia ... and the oldest footprints of Ankylosaurus ever found in the Southern Hemisphere," said Argentine paleontologist Sebastian Apesteguia in Buenos Aires.

Apesteguia, who led a two-week expedition sponsored by Chuquisaca's regional government, thinks the footprints belong to three different kinds of dinosaurs, including Ankylosaurus, an armored herbivore.

He said some of the prints were about 14 inches long, suggesting that the dinosaurs were "medium-sized ... about nine or 10 meters (about 30 feet) in length."

Close to the larger prints, the paleontologists found smaller ones that probably belonged to baby dinosaurs, indicating the offspring "were given some kind of care," Apesteguia said.

Rivera said he first spotted the imprints about 20 years ago, but could never figure out what they were.

A few years ago, he visited a dinosaur park near Sucre, Chuquisaca's regional capital, and noticed that the dinosaur footprints on show resembled the holes near his parent's home.

Sucre is renowned for having the largest set of fossilized dinosaur footsteps ever discovered.

When Rivera bumped into members of Apesteguia's team doing research near his village of Icla, and told them about the holes.

"It was a stroke of luck that this man had been intrigued by the footprints since he was a child," said paleontologist Pablo Gallina, who along with Apesteguia, works for Argentina's Felix de Azara Natural History Foundation.

David Mercado

Utah geologists say they have discovered prehistoric animal tracks so densely packed on a 3/4-acre rock site, they're calling it a "dinosaur dance floor." The site along the Arizona-Utah border is offering a rich new set of clues about the lives of dinosaurs 190 million years ago.

Back then, large stretches of the West were a Sahara-like desert. More than 1,000 tracks were found in what would have been a watery oasis nestled among towering, wind-whipped sand dunes.

Those footprints could provide fodder for future researchers trying to understand dinosaurs that survived in what many considered a "vast, dry, uninhabitable desert," said Marjorie Chan, professor of geology at the University of Utah and one of the authors of a new study of the site.

"Maybe it really wasn't as lifeless as we think," Chan said Monday.

The discovery adds yet another site to the region's long list of dinosaur hot spots. The difference, though, is sheer numbers. Scientists estimate there are more than 1,000 — and perhaps thousands — of tracks at the site, which is in a protected area of Vermilion Cliffs National Monument.

In some places, there are a dozen footprints in a square yard.

"It was a place that attracted a crowd, kind of like a dance floor," Chan said.

Researchers identified four different kinds of tracks in the rock but haven't determined the specific species that left them behind.

Some of the footprints — once thought to be potholes formed by erosion — measure 16 inches across and have three toes and a heel. Others are smaller and more circular.

The area also includes what researchers think are rare tail drag marks.

Winston Seiler, who studied the site for a master's thesis, said the area may have been a popular gathering spot for adults and youngsters alike. The location may have been one of many where Early Jurassic dinosaurs stopped for refreshment before moving along.

Seiler imagines dinosaurs were "happy to be at this place, having wandered up and down many a sand dune, exhausted from the heat and the blowing sand, relieved and happy to come to a place where there was water."

The study's findings were published in the October issue of the science journal Palaios.

"It's an exciting site and deserving of a lot more work," said Jim Kirkland, Utah's state paleontologist, who was not involved with the study.

He's hoping paleontologists begin a large-scale survey of the site to better understand what's there and what stories the tracks might tell.

Dinosaur tracks can provide important insight about dinosaur behavior and movements across the landscape, said Andrew Milner, paleontologist at the St. George Dinosaur Discovery Site at Johnson Farm in southwestern Utah.

The newly discovered site, about three miles from the nearest road, is part of a protected wilderness area that also includes a much-photographed geologic formation called "The Wave" — a gallery of striped, twisted sandstone.

Twenty permits are issued each day to enter the area. Linda Price, the monument's manager, expects interest in the area will jump with word of the dinosaur track site.

"I'm thinking this could be just as big as The Wave," Price said. "It's really, really cool."

MIKE STARK

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Huge Field of Dinosaur Tracks Found

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More than 1,000 dinosaur footprints along with tail-drag marks have been discovered along the Arizona-Utah border. The incredibly rare concentration of beastly tracks likely belonged to at least four different species of dinosaurs, ranging from youngsters to adults.

The tracks range in length from 1 to 20 inches (2.5 to 51 centimeters).

"The different size tracks may tell us that we are seeing mothers walking around with babies," said researcher Winston Seiler, a geologist at the University of Utah.

The tracks were laid about 190 million years ago in what is now the Vermilion Cliffs National Monument.

"There must have been more than one kind of dinosaur there," said researcher Marjorie Chan, professor and chair of geology and geophysics at the University of Utah. "It was a place that attracted a crowd, kind of like a dance floor."

While the site is covered in sand dunes now, the researchers say the tracks are within what was a network of wet, low watering holes between the dunes. In fact, the tracks provide more evidence of wet intervals during the Early Jurassic Period, when the U.S. Southwest was covered with a field of sand dunes larger than the Sahara Desert. >>>>

Archaeologists are racing against the little time left to salvage a fortune in coins and items from a 500-year-old Portuguese shipwreck found recently off Namibia's rough southern coast.

Despite its importance, the project, in a restricted diamond mining area, is itself costing a fortune in sea-walling that cannot be sustained after October 10.

"The vast amounts of gold coins would possibly make this discovery the largest one in Africa outside Egypt," said Francisco Alves, a Lisbon-based maritime archaeologist.

"This vessel is the best preserved of its time outside Portugal," he said.

"But the cultural uniqueness of this find is priceless."

Alves is part of a multi-national team combing the seabed where the wreck was discovered six months ago.

The 16th-century "Portuguese trade vessel was found by chance this April as mine workers created an artificial sand wall with bulldozers to push back the sea for diamond dredging," Namibian archaeologist Dieter Noli told reporters invited to view the site.

"One of them noticed an unusual wooden structure and round stones, which turned out to be cannon balls," he said.

The abundance of objects unearthed where the ship ran aground along Namibia's notorious Skeleton coast, where hundreds of vessels were wrecked over the centuries, has amazed even hardened experts.

Six bronze cannons, several tonnes of copper, huge elephant tusks, pewter tableware, navigational instruments, and a variety of weapons including swords, sabres and knives have all been tugged out of the beach sand.

"Over 2,300 gold coins weighing some 21 kilograms (46 pounds) and 1.5 kilograms of silver coins were found -- worth over 100 million dollars," Alves said, adding that the ship's contents suggest it was bound for India or somewhere in Asia.

"About 70 per cent of the gold coins are Spanish, the rest Portuguese," Alves said. Precise dating was possible thanks to examination of the coin rims that showed "some of them were minted in October 1525 in Portugal."

About 13 tonnes of copper ingots, eight tonnes of tin and over 50 large ivory elephant tusks together weighing some 600 kilograms have also been excavated from the seabed.

-- This discovery is the largest in Africa outside Egypt --

"The copper ingots are all marked with a trident indent, which was used by Germany's famous Fugger family of traders and bankers in Augsburg, who delivered to the Portuguese five centuries ago," said South African archaeologist Bruno Werz.

The team also includes experts from the United States and Zimbabwe, and the salvation efforts were made possible by the erection of sea walls to keep back the fierce Atlantic surf.

Namibia's culture ministry and Namdeb, the state diamond mining company, have shared the enormous expense, which "costs some 100,000 Namibian dollars (12,500 US dollars, 8,500 euros) per day," according to Peingeondjabi Shipoh, the culture ministry expert in charge of the recovery project.

But that is shortly coming to an end, even though "I believe there is still more to be found," he told reporters.

"From October 10, the walls will not be maintained anymore and the ship's remnants left to the elements again."

At one point it was thought the wreck was that of legendary Portuguese explorer Bartolomeo Diaz, the first known European to sail around the southern tip of Africa in 1488.

In line with the custom of Portuguese explorers of the time, Diaz left a huge stone cross to the glory of his country's king, called a "padrao", that same year at what is today's harbour town of Luderitz, which Diaz baptised Angra Pequena or "small cove", 750 kilometres (465 miles) southwest of the capital Windhoek.

Around 1500, he and his sailing vessel went missing and were never found.

But hope that the Oranjemund find might end the mystery was laid to rest when it was established that the coins on the shipwreck were put into circulation 25 years after Diaz' disappearance.

Under international maritime laws, a wreck and its treasures belong to the country where they were found, and all the coins are now locked in the vaults of the Bank of Namibia in Windhoek.

The government said it plans at some point to mount an exhibition of the findings and later erect a special museum in Oranjemund to house the incredible collection.

Brigitte Weidlich

A once-thought virgin forest in a remote area of the Amazon had been in fact a densely populated place. Researchers recently discovered traces of widespread human activity which contradicts the anthropologists’ theory that the only cradle of "urbanism" in pre-Columbian South America was in the Andes Mountains.

Archeologists found traces of a numerous settlements that were connected by road networks and had been built around plazas. There was also evidence of the main activities of the dwellers of that urban community such as farming, wetland management, and fishing.

According to the research report, the settlement dates back to the period prior to when the Europeans discovered that part of the continent. The "medieval" urban community was located in the Upper Xingu region of the Brazilian Amazon.

"These are not cities, but this is urbanism, built around towns," said Professor Mike Heckenberger, from the University of Florida.

Heckenberger said he was amazed by the "remarkable planning and self-organization." The villages were built in clusters following geometric patterns comparable to the European villages in that same era.

The urban community was surrounded by large walls composed of earthworks. Each road was pointing north-east to south-west in order to keep with the mid-year summer solstice. Researchers also found a series of dams and artificial ponds which the dwellers used for fish farming. Researchers believe the urban community of Upper Xingu was composed of tens of thousands of people.

The main reason why urbanism was a very rare thing in the Amazon during that period was the fact that local people did not have the ability to centralize production of resources and did not believe they really needed to centralize into cities.

The inhabitants of those settlements are thought have been wiped out when the European colonists arrived there.

Alexander Toldt

A turtle that toddled alongside the dinosaurs died just days before laying a clutch of eggs. Now, about 75 million years later, paleontologists are announcing their find of the fossilized mother-to-be and the eggs tucked inside her body.

Scientists from the Royal Tyrrell Museum of Palaeontology in Canada discovered the turtle in 1999 in a mud-filled channel in the badlands of southeastern Alberta. Then, in 2005, University of Calgary scientists found a nest of 26 eggs laid by another female of the same species in the same region.

Both specimens, described this week in the journal Biology Letters, belong to an extinct turtle in the Adocus genus, a large river turtle that resembles today's slider and cooter turtles.

The pregnant turtle represents the first fossil turtle to be unearthed with eggs still inside the body cavity, the scientists say.

"Although it is relatively rare to find the eggs and babies of extinct animals, it is even rarer to find them inside the body of the mother," said researcher Darla Zelenitsky, a geoscientist at the University of Calgary in Alberta, who was also involved in the first discovery of a dinosaur with eggs inside its body.

Fertile find

It was almost by accident that scientists realized that the fossil turtle had been pregnant.

"The reason we knew she was pregnant was because when the fossil was found the body was broken," Zelenitsky told LiveScience, "so there was egg shell on the ground just below the fossil, it was falling out of the body."

The team spotted at least five crushed eggs within the body of the fossilized female, and computed tomography (CT) scans revealed more eggs hidden beneath the turtle's shell. The turtle, estimated to be about 16 inches (40 cm) long, could have produced about 20 eggs.

When still intact, the eggs would have been spherical and about 1.5 inches (4 cm) in diameter. The eggs from the nearby nest were about the same size and shape. Both sets of eggs also had extremely thick and hard shells, especially compared with most modern turtles whose shells are either thinner or soft.

Thick-shelled

The thick eggshell may have evolved to protect the eggs from drying out or from voracious predators that lived during the Age of Dinosaurs.

The pregnant turtle and nest specimens, the researchers say, shed light on the evolution of reproductive traits of modern turtles.

"Based on these fossils, we have determined that the ancestor of living hidden-necked turtles, which are most of today's turtles and tortoises, laid a large number of eggs and had hard, rigid shells," said François Therrien, the Museum's Curator of Dinosaur Palaeoecology, who worked on the turtle report in the journal.

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Jeanna Bryner

Archeologists working at Peru's Huaca Pucllana ruins pulled a mummy from a tomb on Tuesday, thought to be from the ancient Wari culture that flourished before the Incas.

Besides the female mummy, the tomb contained the remains of two other adults and a child. It is the first intact Wari burial site discovered at Huaca Pucllana in the capital Lima, and researchers believe it dates from about 700 AD.

"We'd discovered other tombs before," said Isabel Flores, director of the ruins. "But they always had holes, or were damaged. Never had we found a whole tomb like this one -- intact," she said, standing on the ancient plaza, a huge partially excavated mound of rocks, bricks and dirt.

Workers wrapped the female mummy in tissue paper before lifting it onto a flat wood board. They exposed her face, revealing two big, bright blue orbs in her eye sockets. They extracted the other adult mummies, which were also whole, earlier in the week.

"Her face startled me at first," said Miguel Angel, 19, a worker at Huaca Pucllana who helped unearth the tomb.

"I wasn't expecting to find anything like that," he said. It was not clear what the fake eyes were made of.

The Wari people lived and ruled in what is now Peru for some 500 years, between 600 AD and 1100 AD. Their capital was near modern-day Ayacucho, in the Andes, but they traveled widely and are known for their extensive network of roads.

Flores said about 30 tombs have been found at Huaca Pucllana, surrounded by Lima's busy streets.

When in good condition, Wari tombs can be identified by the ceramic and textile offerings placed around the dead.

Small children were often sacrificed and it is common to find their bodies alongside adult ones. The child discovered with the adult mummies at Huaca Pucllana was likely sacrificed.

The discovery at Huaca Pucllana confirms the Wari people buried their dead in what is now Lima and offers a more complete picture of how burials were done. "This enriches Lima's story," Flores said.

Dana Ford

An ancient tar pit exposed when Venezuelan oil workers laid a pipeline has yielded a rich trove of fossils, including a type of saber-toothed cat that paleontologists had never found before in South America. Scientists say the find holds the promise of many discoveries to come.

The fossils are 1.8 million years old and include skulls and jawbones of six scimitar-toothed cats — a variety of saber-toothed cat with shorter, narrower canine teeth than other species.

Researchers led by Venezuelan paleontologist Ascanio Rincon announced the discovery this month, saying in addition to proving the cat once lived here, the find also should offer a rare window into the environment shortly after North and South America became connected following an age of separation.

"The deposit could be one of the most important in South America in the last 60 years," Rincon told The Associated Press.

Other experts agree.

"The find is one of the most spectacular and scientifically interesting discoveries of the last decade," said University of Kansas professor Larry D. Martin, an expert on saber-toothed cats who was not involved in the find. "The genus hadn't been known from South America before."

The tar pits are larger than two football fields and near the surface of the soil in the eastern state of Monagas, an oil-rich area.

The state oil company set aside the site for research in 2006 and contacted Rincon at the Venezuelan Institute for Scientific Studies. After months of digging, he and his team found the prized fossils in April 2007.

But for the past year, Venezuela's Cultural Heritage Institute has inexplicably barred researchers from the site, which Rincon says has left it exposed to sun and rain, and potentially damaged the fossils.

The Cultural Heritage Institute revoked Rincon's permit last year, and has yet to publicly explain why. Rincon said his institution is negotiating with the agency so that researchers may return.

Rincon first spoke of the discovery at a symposium on scimitar-toothed cats in Pocatello, Idaho, in May.

Rincon and other researchers say the find suggests scimitar-toothed cats — of the genus Homotherium — crossed from North America to South America shortly after the continents grew together and became linked in modern-day Panama following a 65-million-year separation, a "moment of great exchange" between the continents.

Another expert, Argentine paleontologist Francisco Prevosti, called the Venezuelan discovery of "utmost importance for South American paleontology."

Prevosti and other experts say the now-extinct scimitar-toothed cat was previously confirmed to have inhabited Africa, Europe, Asia and North America — but not South America.

FABIOLA SANCHEZ

A tiny woman and two children were laid to rest on a bed of flowers 5,000 years ago in what is now the barren Sahara Desert. The slender arms of the youngsters were still extended to the woman in perpetual embrace when researchers discovered their skeletons in a remarkable cemetery that is providing clues to two civilizations who lived there, a thousand years apart, when the region was moist and green.

Paul Sereno of the University of Chicago and colleagues were searching for the remains of dinosaurs in the African country of Niger when they came across the startling find, detailed at a news conference Thursday at the National Geographic Society.

"Part of discovery is finding things that you least expect," he said. "When you come across something like that in the middle of the desert it sends a tingle down your spine."

Some 200 graves of humans were found during fieldwork at the site in 2005 and 2006, as well as remains of animals, large fish and crocodiles.

"Everywhere you turned, there were bones belonging to animals that don't live in the desert," said Sereno. "I realized we were in the green Sahara."

The graveyard, uncovered by hot desert winds, is near what would have been a lake at the time people lived there. It's in a region called Gobero, hidden away in Niger's forbidding Tenere Desert, known to Tuareg nomads as a "desert within a desert."

The human remains dated from two distinct populations that lived there during wet times, with a dry period in between.

The researchers used radiocarbon dating to determine when these ancient people lived there. Even the most recent were some 1,000 years before the building of the pyramids in Egypt.

The first group, known as the Kiffian, hunted wild animals and speared huge perch with harpoons. They colonized the region when the Sahara was at its wettest, between 10,000 and 8,000 years ago.

The researchers said the Kiffians were tall, sometimes reaching well over 6 feet.

The second group lived in the region between 7,000 and 4,500 years ago. The Tenerians were smaller and had a mixed economy of hunting, fishing and cattle herding.

Their burials often included jewelry or ritual poses. For example, one girl had an upper-arm bracelet carved from a hippo tusk. An adult Tenerian male was buried with his skull resting on part of a clay vessel; another adult male was interred seated on the shell of a mud turtle.

And pollen remains show the woman and two children were buried on a bed of flowers. The researchers preserved the group just as they had been for thousands of years.

"At first glance, it's hard to imagine two more biologically distinct groups of people burying their dead in the same place," said team member Chris Stojanowski, a bioarchaeologist from Arizona State University.

Stojanowski said ridges on the thigh bone of one Kiffian man show he had huge leg muscles, "which suggests he was eating a lot of protein and had an active, strenuous lifestyle. The Kiffian appear to have been fairly healthy — it would be difficult to grow a body that tall and muscular without sufficient nutrition."

On the other hand, ridges on a Tenerian male were barely visible. "This man's life was less rigorous, perhaps taking smaller fish and game with more advanced hunting technologies," Stojanowski said.

Helene Jousse, a zooarchaeologist from the Museum of Natural History in Vienna, Austria, reported that animal bones found in the area were from types common today in the Serengeti in Kenya, such as elephants, giraffes, hartebeests and warthogs.

The finds are detailed in reports in Thursday's edition of the journal PLoS One and in the September issue of National Geographic Magazine.

While the Sahara is desert today, a small difference in Earth's orbit once brought seasonal monsoons farther north, wetting the landscape with lakes with lush margins and drawing animals and people.

The research was funded by National Geographic, the Island Fund of the New York Community Trust, the National Science Foundation and the Wenner-Gren Foundation for Anthropological Research.

RANDOLPH E. SCHMID

Archaeologists have unearthed a 1,900-year-old well-preserved chariot at an ancient Thracian tomb in southeastern Bulgaria, the head of the excavation said Thursday.

Daniela Agre said her team found the four-wheel chariot during excavations near the village of Borisovo, around 180 miles east of the capital, Sofia.

"This is the first time that we have found a completely preserved chariot in Bulgaria," said Agre, a senior archaeologist at the Bulgarian Academy of Sciences.

She said previous excavations had only unearthed single parts of chariots — often because ancients sites had been looted.

At the funerary mound, the team also discovered table pottery, glass vessels and other gifts for the funeral of a wealthy Thracian aristocrat.

In a separate pit, they unearthed skeletons of two riding horses apparently sacrificed during the funeral of the nobleman, along with well preserved bronze and leather objects, some believed to horse harnesses.

The Culture Ministry confirmed the find and announced $3,900 in financial assistance for Agre's excavation.

Agre said an additional amount of $7,800 will be allocated by the Bulgarian Academy of Sciences for an initial restoration and conservation of the chariot and the other Thracian finds.

The Thracians were an ancient people that inhabited the lands of present day Bulgaria and parts of modern Greece, Turkey, Macedonia and Romania between 4,000 B.C. and the 6th century, when they were assimilated by the invading Slavs.

Some 10,000 Thracian mounds — some of them covering monumental stone tombs — are scattered across Bulgaria.

VESELIN TOSHKOV

Egyptian scientists are carrying out DNA tests on two mummified fetuses found in the tomb of King Tutankhamun to determine whether they are the young pharaoh's offspring, the antiquities authority said Wednesday.

The two tiny female fetuses, between five to seven months in gestational age, were found in King Tut's tomb in Luxor when it was discovered in 1922.

DNA samples from the fetuses "will be compared to each other, along with those of the mummy of King Tutankhamun," the head of the Supreme Council of Antiquities, Zahi Hawass, said in a statement.

The testing is part of a wider program to check the DNA of hundreds of mummies to determine their identities and family relations. Hawass said the program could help determine Tutankhamun's family lineage, which has long been a source of mystery among Egyptologists.

The identity of Tut's parents is not firmly known. Many experts believe he is the son of Akhenaten, the 18th Dynasty pharaoh who tried to introduce monotheism to ancient Egypt, and one of Akhenaten's queens, Kiya. But others have suggested he was the son of a lesser known pharaoh who followed Akhenaten.

Scholars believe that at age 12, Tutankhamun married Ankhesenamun — a daughter of Akhenaten by his better known wife Nefertiti — but the couple had no surviving children. There has been no archaeological evidence that Tut, who died around the age of 19 under mysterious circumstances over 3,000 years ago, left any offspring.

Tutankhamun was one of the last kings of Egypt's 18th Dynasty and ruled during a crucial, turmoil-filled period when Akhenaten's monotheism was ended and powers were returned to the priests of ancient Egypt's multiple deities.

The council said that if the tiny mummies are unrelated to Tut, they may have been placed in his tomb to allow him to "live as a newborn in the afterlife."

Ashraf Selim, a radiologist and member of the Egyptian team, said the tests could take several months. So far, the team has carried out CT scans on the two fetuses and taken samples for DNA tests.

"We want to find out the truth and facts relevant to the history of these kings," Selim told The Associated Press.

Since they were found in King Tut's tomb, the mummified fetuses were kept in storage at the Cairo School of Medicine and were never publicly displayed or studied, Selim said.

Hawass has announced ambitious plans for DNA tests on Egyptian mummies, including tests on all royal mummies and the nearly two dozen unidentified ones stored in the Egyptian Museum in Cairo. He has said the tests may show that some royal mummies on display are not who archaeologists thought them to be.

One of his top goals is to find the mummy of Nefertiti, the queen legendary for her beauty.

Last year, Egypt announced that archaeologists had identified the mummy of Hatshepsut, Egypt's most powerful queen and the only female pharaoh. But scientists later said they were still analyzing DNA from the bald, 3,500-year-old mummy to try to back up the claim.

Hawass has long rejected DNA testing on Egyptian mummies by foreign experts, and only recently allowed such projects on condition they be done exclusively by Egyptians. A $5 million DNA lab was created at the Egyptian Museum, with funding from the Discovery Channel.

But some experts have warned that Hawass is making claims like that of Hatshepsut too quickly, without submitting samples to a second lab to corroborate DNA tests or publishing the results in peer-reviewed journals, both common practice.

The council announced in its statement Wednesday that the government had agreed with Cairo University's Faculty of Medicine to open a second DNA testing lab, though it did not give details on funding for the lab or when it could begin work.

Abdel-Halim Nour el-Deen, a former head of the council and a leading Egyptologist said DNA testing on mummies thousands of years old is very difficult.

"It is doubtful that it could produce a scientific result to determine such important issues such as the lineage of pharaohs," Nour el-Deen told the AP.

Nour el-Deen also criticized the antiquities authority for not making public the results of the tests already carried out.

SALAH NASRAWI