Thursday, April 14, 2005
Croc Skulls Prompt Rethinking
From an AFP report:
The fossilized skulls of two large crocodile-like amphibians, recovered from the sun-scorched Niger desert, are prompting palaeontologists to rethink the evolutionary path taken by four-legged beasts in Earth's distant past...
Until now, the supposition has been that Permian tetrapods (four-legged creatures) were rather tediously similar.
But the latest fossils, along with other discoveries made in Niger in the past few years, suggests that species diversification was well underway 250 million years ago.
During this time, the Earth had seasons that were alternative hot and humid, especially in equatorial zones, and a vast southern polar ice cap began to melt.
The notion of homogeneity during the Permian is "probably over-simplified," for the humble reason that there has been little effort to dig out fossils in tough regions like the Sahara, the authors suggest.