Dinos' demise spurred rise of the mammals, new fossil suggests

0 Comments | AFP, June, 2007

PARIS (AFP) — A fossil discovered in the Gobi Desert has unlocked the most emphatic evidence to date that the mass extinction of the dinosaurs helped placental mammals -- of which Homo sapiens is a member -- become masters of the planet.

The fossilised skull of a shrew-like creature was uncovered in Mongolia in 1997 but only now have scientists become aware of its importance, according to a paper published on Thursday by Nature, the weekly British science journal.

A big debate in paleontology is when our mammalian forebears first appeared on the scene.

Some experts, using a "molecular clock" based on the rate of DNA mutation, say placental mammals may have popped up as early as the start of the Cretaceous era, some 145 million years ago.

Others put...