Prosalirus bitis is the name given to a fossil frog found in Arizona in 1981 by Farish Jenkins, which has primitive features, but has mostly lost the salamander-like traits of its ancestors. It has a skeleton designed to absorb the force of jumping with its hind legs and tail. It also has long hip bones, long hind leg bones, and long ankle bones, all similar to modern frogs, and is, as of 2009, the earliest such frog. The name comes from the Latin verb prosalire, meaning 'to leap forward'. It is thought to have lived 190 million years ago, well before the first known modern frog, Callobatrachus. As of 2009, only three Prosalirus skeletons have been discovered.