Bolivian dinosaur trackways

[bh480@scn.org]

From: Ben Creisler bh480@scn.org

In case this new story has not been mentioned yet:
http://www.ipsnews.net/news.asp?idnews=29101

BOLIVIA:
Dinosaur Tracks Rewrite Palaeontology
José Luis Alcázar* 

LA PAZ, Jun 16 (Tierramérica) - The more than 5,000 
dinosaur footprints discovered in Cal Orko, in southern 
Bolivia, have prompted a reconstruction of the planet's 
history and a correction of the science about these 
gigantic animals that dominated the landscape until some 
65 million years ago, when they disappeared from the face 
of the Earth. 

That is the main conclusion of the international 
scientific team led by Swiss palaeontologist Christian 
Meyer, director of the Basil Natural History Museum and 
dean of that Swiss city university's palaeontology 
department, which in 1998 certified the existence of the 
dinosaur tracks three kilometres outside of Sucre, 
Bolivia. 

The palaeontology site, discovered in a quarry of a cement 
factory, is ''far and away the largest site of dinosaur 
tracks found so far,'' said Meyer. 

The discovery is an enormous contribution to humanity and 
to science, revealing data heretofore unknown about the 
final period of the Cretaceous period and the beginning of 
the Tertiary period, some 66 million years 
ago, ''documenting the high diversity of dinosaurs better 
than any other site in the world,'' said the expert, who 
has been travelling the world for more than 15 years 
searching for and uncovering dinosaur tracks. 

Before Cal Orko, the biggest known site was Khjoda-Pil-
ata, in Turkmenistan, and there are other large sites in 
Portugal, Britain, Spain and Switzerland. But the Bolivian 
site ''is several times larger than any of them,'' Meyer 
said. At each of the other sites, scientists had found up 
to 220 tracks from two species. 

The immense Bolivian site is the rock face of an 
outcropping on a slant of 73 degrees, 80 metres high and 
1.2 km long. There are tracks of 294 different dinosaurs 
made during the second half of the Cretaceous period. 

The first news of the Bolivian palaeontological site dates 
back to 1985, but it was from 1994 to 1998 that a team of 
25 palaeontologists -- from Bolivia, Europe and United 
States -- studied and certified the bed of tracks, under 
Meyer's direction. 

During the Cretaceous, Cal Orko was part of an immense 
shallow lake. In the Tertiary, when the Andes Mountains 
were formed, the movement of the tectonic plates pushed 
the former lake bed vertically. Not far from this site, 
eight others have been found in recent years and are 
currently being studied. 

Meyer, vice-president of the European Association of 
Palaeontologists, explained to Tierramérica that before 
the Bolivian discovery, it was believed that dinosaurs 
began disappearing gradually from the Jurassic to the 
Cretaceous period, and that at the end of the latter, the 
few surviving species died off suddenly en masse. 

But ''the 'dino-diversity' is very great in Orko and 
amends the debate about the gradual decline until the end 
of the Cretaceous. We have discovered that in this latest 
period, when massive extinction occurred, the existence of 
the dinosaurs was vast and much more varied than was 
believed until now. The whole collection is right there,'' 
said Meyer. 

One of the discoveries that astonished him were the 
footprints of the anchylosaurus, a quadruped herbivore 
that was not believed to have lived in South America. This 
animal was represented as a sort of giant, awkward 
armadillo weighing eight tonnes, but ''the study of its 
tracks in Orko describes for us a saurus much taller and 
thinner, with longer and lighter legs,'' he said. 

Now it will be necessary to reconstruct the models of 
skeletons on exhibit in the museums of the world and 
rewrite the descriptions, said the scientist. 

Also found in Cal Orko were traces of the herbivore 
sauropods, including the gigantic titanosaurus, measuring 
25 metres tall and with footprints 70 cm in diameter; and 
the big predators like the theropods, with 35-cm 
footprints. 

Fossils of turtles, crocodiles, fish and seaweed from the 
Later Cretaceous were found, allowing the palaeontologists 
to carry out more rigorous studies of the period. 
Previously data about life at that time was relatively 
scarce. 

It is thought that dinosaurs arrived in South America, 
from North America, towards the end of the Jurassic 
(around 145 million years ago), or, according to another 
theory, they arrived from Africa before the continents 
were separated 235 million years ago. 

To contribute to preserving the site, a Cretaceous Park is 
slated to open in March 2006. Replicas of different 
dinosaur species will welcome visitors to a museum with 
audiovisual exhibits, transporting them -- at least in 
their imaginations -- to prehistoric time. 

The park project organisers announced that they are 
working on protecting the extensive face of the 
outcropping, but Meyer warns that ''before building the 
park it is essential to shore up the wall, because there 
is an active tectonic fault in the middle of it. If it 
isn't stabilised, it will collapse and the future park 
will be left without its major attraction, and humanity 
will lose part of the planet's history.'' 

(* José Luis Alcázar is a Tierramérica contributor. 
Originally published Jun. 11 by Latin American newspapers 
that are part of the Tierramérica network. Tierramérica is 
a specialised news service produced by IPS with the 
backing of the United Nations Development Programme and 
the United Nations Environment Programme.)