A mammal fossil takes wing
Categories : Evolution, Front-loading
Editor : Krauze
published: jeudi 21 décembre 2006 1:44:37
Traditional thinking held that during the age of dinosaurs, mammals were scrawny little things, confined to the crevices of a world ruled by the large reptiles. But a new fossil shows that mammals were a far more diverse group.
Writing in last week's edition of Nature, Jin Meng and his colleagues describe the fossil of a gliding mammal found in China. The fossil is similar to modern-day flying squirrels, with a skin membrane stretched out between fore- and hind-limbs, presumably enabling it to glide from tree to tree.
That mammals were so specialized while dinosaurs still walked the earth spells trouble for the theory, popularized in Stephen Jay Gould's Wonderful Life, that mammals only flurried after the extinction of the dinosaurs, and that, had it not been for a meteor slamming in the planet, our mammalian forefathers would still be eeking out a living in the shadow of the dinosaurs. This discovery, and others like it, suggests that evolution may not be as random as we thought.