Sahara Desert Yields Ancient Amphibious Fossils
MONTREAL, Quebec, Canada, April 15, 2005 (ENS) - The fossilized skulls of two new species of large, meat eating amphibians have been discovered by researchers in the Sahara desert of Niger in West Africa. The fossils are believed to be 250 million years old - the first and oldest amphibious carnivores found in the arid, low-lying region.
Until they saw these fossils, scientists had believed animals like these had gone extinct 40 million years earlier, around 290 million years ago.
Seven organizations from five countries cooperated in this research, which is reported today in the journal "Nature." The lead scientists from Niger are Dr. Oumarou Ide and Dr. Abdoulaye Maga of the Institut de Recherches en Sciences Humaines in Niamey.
"This the first evidence of carnivores in this area," says McGill University paleontologist, and co-author, Hans Larsson. "This find is particularly interesting because the animals we found are not present anywhere else in the world at that time. These animals seemed to be restricted to this one region of Africa that had one of the driest climates on the planet."
"Animal communities found in other parts of the world are similar to each other, but completely different from those in Niger," said Larsson. "We think the shared temperate climates of these other communities may have forced them to evolve independently and in relative isolation from the Niger fauna."
Because they were amphibious, the scientists believe there was some water in the region when they were alive. The two species of amphibians are similar to crocodiles in shape.
Nigerpeton ricglesi had rounded noses, with small eyes and both small and large fang-like teeth. The animal measured about three meters, seven to eight feet, said researchers.
Saharastega moradiensis, which measured about two meters, five to six feet, had curved 'horns' on the back of its head and an array of small teeth.
Niger expeditions assisted by Larsson have led to the discovery of eight unknown species of dinosaurs and five new types of crocodiles. Among his co-discoveries was a dog-sized dinosaur, baptized "deltadromeus," and a 40 ton afroventor.
"Niger is a very unexplored country," he says. "Almost everything we find there is completely new to science."
But Niger is not easy to navigate. Research teams must travel by Hummer caravans using a Global Positioning System. Arabic-to-English translators are hired to help locate dinosaur bone-beds, which many locals misinterpret as being camel graveyards. Civil wars have made expeditions treacherous. Researchers also worry about snakes and scorpions.
This group of researchers has been studying the fossil beds of Niger for years. On a Niger expedition in 2000, paleontologist Christian Sidor of the New York College of Osteopathic Medicine unearthed five foot long jawbones from an ancient 40 foot crocodile, the Sarcosuchus imperator.
Sidor and the other scientists are seeking new information about therapsids, the dominant land animals between 230 million and 260 million years ago, before the dinosaurs. At the time they lived in the Late Permian era, Earth's land area was not separated into the continents familiar to us. Just one giant continent existed called Pangea. The research team believes their finds were isolated in the center of Pangea by climatic conditions.
The discovery of ancient species has much to teach people who are alive today, Larsson says. "Our findings show that climate change more than 250 million years ago had a dramatic effect on species survival and evolution. Something to keep in mind when evaluating similar changes in today's world."
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