OCUCAJE, Peru  Nestled between the Andes and the Pacific, the sparse desert surrounding this outpost in southern Peru looks like one of the world’s most desolate areas. Barren mountains rise from windswept valleys. Dust devils dance from one dune to the next.

But to the bone hunters who stalk the Ocucaje Desert each day, the punishing winds here have exposed a medley of life and evolution: a prehistoric graveyard where sea monsters came to rest 40 million years ago. These parched lands, once washed over by the sea, guard one of the most coveted troves of marine fossils known to paleontology.

Discoveries here include gigantic fossilized teeth from the legendary 50-foot shark called the megalodon, the bones of a huge penguin with surprisingly colorful feathers and the fossils of the Leviathan Melvillei, a whale with teeth longer than those of the Tyrannosaurus rex, making it a contender for the largest predator ever to prowl the oceans.

“This is perhaps the best area in the world for marine mammals,” said Christian de Muizon, 58, a paleontologist at the Natural History Museum in Paris who led an expedition here in November. He ranks the Ocucaje (pronounced oh-coo-CAH-heh) and adjacent sections of desert with top fossil areas like Liaoning Province in China, where ashfall famously preserved plumed dinosaurs.