|Patagonia Vulture Valley Yields New Top Dinosaur|
LA BUITRERA, Argentina (Reuters) -Herdsman Raul Avelas was nonplused when he spied huge bones on his patch ofArgentina's badlands a decade ago, seeing them as just another protrusion forhis flock to stumble over en route to his adobe homestead.
"Since I started walkingaround the countryside here as a boy I've seen several bones, but I never gaveit much importance," Avelas said, adjusting his black beret and picking athis brown-stained teeth.
But Buenos Aires paleontologistSebastian Apesteguia knew otherwise after chatting with Avelas a year ago. Thefossils he and his seven-man team have since unearthed from a desolate,vulture-ridden cliff at La Buitrera (The Vulture Cage) in southern Argentina'sPatagonia are believed to be from the biggest dinosaur species ever discovered.
"There is nothing comparableto this so it is probably a new species," the wiry Apesteguia said. Thetip-off were the two cervical vertebrae each measuring 3.84 feet, the biggestever unearthed.
"They were so big they seemedlike a femur or tibia, but on closer examination they turned out to be neckvertebrae," said Jorge Gonzalez, a technical artist from the ArgentineNatural Sciences Museum in Buenos Aires who is in on the dig.
With 10 to 12 vertebrae making upthe neck, scientists envision a plant-eating sauropod stretching 154-160 feetfrom head to tail and towering 45 feet. That is roughly half a city block longand five stories high.
The closest rival is theArgentinosaurus discovered in the same region. It was the largest type ofdinosaur ever found but the new find is 26 feet longer and sports the same bodyshape: small head, serpentine neck, barrel-shaped middle and a long tail. Itweighed in at 80 metric tons or more.
La Buitrera is about 50 miles asthe buzzard flies from the town of Cipolletti in southern Rio Negro province. Itis sparse land full by thorny scrub where the air smells like a rich combinationof oregano and mint and temperatures regularly soar over 104 degrees.
The big-sky flatlands areinhabited by nandus (American ostriches), mountain goats and wild horses. Italso contains mule skeletons picked bare by vultures and a cache of dinosaurbones rivaling those of China's Gobi Desert and western Canada's Albertaprovince.
"Rio Negro is very large andinhospitable and there's a lot of bones here off the beaten track,"Apesteguia said.
Dagger-toothed Giganotosaurus, abigger version of Tyrannosaurus Rex and the largest flesh-eater ever identified,was uncovered nearby in 1993, along with another carnivore still being studiedthat may be even bigger. Hundreds of dinosaur eggs were also found in an extinctvolcano in 1998.
"The lush vegetation broughtthe plant-eaters and they in turn attracted the meat-eaters," saidpaleontologist Carlos Munoz, head of the Florentino Ameghino museum inCipolletti.
In the Cretaceous period 100million years ago, La Buitrera was a forested plain dotted by lakes and sluicedby a huge river that probably flowed into the Pacific, unobstructed by the Andesmountain range, which had yet to be born. Bones of dinosaurs that died along theriver were swept downstream and dumped on a bank that is now hard, brownsedimentary rock.
The fossils of what is believed tobe the largest animal ever on Earth were found by Avelas on a ridge overlookingthe canyon left by the river. The spot is perched atop the 128-foot walls of thegorge, which is too narrow in sections for access by vehicle or even horse.
Up to now the colossal dinosaurbeing unearthed there has simply been tagged the "Rio Negro Giant,"Munoz said.
Craning its long neck to eatfruits and leaves from the trees dotting the plain, the vegetarian beastprobably ran in packs in the style of elephants, Gonzalez said.
Its awesome bulk offered itprotection from marauding meat-eaters, whom it probably fended off with itsenormous tail, he said. "Carnivores probably attacked the young, who wereeasier to topple."
The "Rio Negro Giant"now consists of some 20 individual body parts including femurs, ribs and tailbones that lie strewn about the excavation site, patiently worked on eight hoursa day with picks, brushes and plaster by the team of Argentine biologists,technicians and paleontology students.
Because of their lofty perch inthe tight canyon and their combined weight exceeding 440 pounds, the specimenswill most likely have to be flown out by helicopter to the Florentino Ameghinomuseum, Munoz said. "We're going to try to get all the visible bones out ofhere by the end of January."
The dinosaur diggers will thenretire until school is out early in 2001, when the tap-tap of picks will echothrough the canyon once again. Besides shards from the largest beast that everroamed the planet, other pieces are expected to turn up.
"Here we've found crocodiles,sharks, birds, snakes, eggs, meat-eaters, plant-eaters, you name it. This placehas got them all," Munoz said.
Emphasizing the point, Apesteguiatakes a small reddish-brown crocodile head fossil out of its protectivenewspaper like someone unwrapping a fragile crystal vase.
"There are dinosaurseverywhere," he said. "The point is that here they arepreserved."