The world's smallest species of snake, with adults averaging just under 4 inches in length, has been identified on the Caribbean island of Barbados. The species -- which is as thin as a spaghetti noodle and small enough to rest comfortably on a U.S. quarter -- was discovered by Blair Hedges, an evolutionary biologist at Penn State. Hedges and his colleagues also are the discoverers of the world's smallest frog and lizard species, which too were found on Caribbean islands. The most recent discovery will be published on Aug. 4 in the journal Zootaxa.

It has long been known that snakes are descendants of lizards, but whether snakes lost their legs while living in the sea or on land has been a matter of great debate among evolutionary biologists. Only one group of marine lizards, the mosasaurs, lived during the Cretaceous period when snakes first appear in the fossil record. These extinct relatives of the Komodo dragon have a skeleton that is much like a snake's (albeit 30 feet long), provoking some researchers to speculate that the snake family descended from mosasaurs.