SCIENCE LAB SCENICS : TURTLES EVOLUTION

SHELL GAME : How did turtles evolve? Faster than you'd expect : Turtles move around in their armored sanctuary, have adapted to living on land and in water and are among the longest-living animals on the planet.

Their anatomy is so unusual that it's hard to pinpoint where they belong on the tree of life. Where do they come from? Who, scientists would love to know, is their common ancestor?

Many paleontologists have asserted that turtles originated with an ancient reptime, Eunotosaurus africanus, which lived 260 million years ago. 2

Other studies that focused on genetic evidence, have suggested that turtles are actually more similar to crocodiles and birds and may share a common ancestor with them.

'' Turtle origins have always been a tough nut to crack,'' said Xavier A. Jenkins, with the American Museum of Natural History in New York City.

In a new study in Current Biology, Dr. Jenkins and his colleagues say they have resolved this longstanding debate.

They suggest that turtles are not holdovers from ancient Eunotosaurus, but are instead members of a group of reptiles called archosauromorphs that also includes ancient birds, crocodiles, pterosaurs and dinosaurs.

And this time, the researchers have the anatomical evidence to match the DNA.

[ Skeletal reconstructions are available of Protorosaurus, about 250-260 million years ago ; Pappochelys, from 240 million years ago ; and Proganochelys, from 220 million years ago.]

When turtles first evolved, the world was just emerging from the Permian - Triassic extinction event.

Reptiles were fanning out across the Pangea supercontinent in a rapid succession of new forms.

!WOW! thanks Sara Novak.