Common Ancestor of Mammals Is Plucked From Obscurity [View all]
Humankindís common ancestor with other mammals may have been an animal the size of a rat that weighed no more than half a pound, had a long furry tail and lived on insects.
In a comprehensive six-year study of the mammalian family tree, scientists have identified and reconstructed what they say is the most likely common ancestor of the species on the most abundant and diverse branch of that tree. The work appears to support the view that in the global extinctions some 66 million years ago, all non-avian dinosaurs had to die for mammals to flourish.
A team of researchers described the discovery as an important insight into the pattern and timing of early mammal life and a demonstration of the capabilities of a new system for handling copious amounts of fossil and genetic data in the service of evolutionary biology. The formidable new technology is expected to be widely applied in years ahead to similar investigations of plants, insects, fish and fowl.
As researchers reported Thursday in the journal Science, a lowly occupant of the fossil record, Protungulatum donnae, had several anatomical characteristics for live births that anticipated all placental mammals leading to some 5,400 living species, from shrews to elephants, bats to whales, cats to dogs and, not least, humans capable of reconstructing such playbacks of evolutionís course.