Spelunking and traditional cave diving are both a lot of fun. There is danger in scuba-diving flooded caves, but experienced explorers will tell you that the unique sights that can be found just beneath waves and stone are worth the risk. Such was the case for Ryan Dart, an Australian diver who made the paleontological discovery of a lifetime after stumbling upon a "treasure trove" of ancient and massive lemur bones.

Of course, Dart didn't simply stare in awe at what archaeologists are calling a "motherload" and move on. He called in connections, first contacting Phillip Lehman, a diver for the Dominican Republic Speleological Society, who in-turn got hold of Alfred Rosenberger, a primate paleontologist at Brooklyn College.

Understanding the importance of this discovery, Rosenberger than scraped together a team of experts, winning funding from the National Geographic Society and the National Science Foundation (NSF) to investigate where Dart was swimming - Malaza Manga, Aven, and Mitoho, in Tsimanampesotse National Park in southwest Madagascar. These areas were found to contain ancient remains that have lay untouched for thousands of years, including full skeletons of giant lemurs, elephant birds, horned crocodiles, and Malagasy hippos

"The possibilities here of making important and exciting discoveries is phenomenal, because nothing like this has ever been found before," Rosenberger excitedly explained in a recent NSF video.

"Caves are wonderful places for the collection of subfossils (bones that have not yet turned to stone)," Laurie Godfrey, a specialist on ancient lemurs who was called in specifically to help examine the mass lemur grave that Dart found, added in a statement. (Scroll to read on...)

"We want to retrieve the story," Godfrey said, explaining how the researchers are currently investigating how so many full skeletons had accumulated at these cave openings. They hope to perhaps identify details that surveying paleontologists can look for in the future to help find other "motherloads."

Rosenberger went on to add that the most exciting of the discoveries was the complete skull of a large and long-extinct lemur ancestor called Megaladapis.

"Megaladapis is a fascinating critter" he said, explaining that the animal, informally known as a 'koala-lemur,' looked like a bizarre pear-bodied cross between the two modern species. "It had a very long skull, about a foot long in size, with a kind of stocky robust body." (Scroll to read on...)

The unique animal was very different from lemurs today and is a prime example of an ancient species that mysteriously disappeared. As Madagascar has limited migration options but impressive biodiversity even today, the researchers hope that fossils like this latest skull will help reveal how some species naturally went exinct - an important detail as conservationists work to distinguish nature running its course from human influence today.

The excavation is still ongoing, and this initial investigation was only the first phase of a multi-year project. So far only a small percentage of the bones in each cave have been recorded, and Godfrey expects that the team has quite a lot of work ahead of them.

For more great nature science stories and general news, please visit our sister site, Headlines and Global News (HNGN).

- follow Brian on Twitter @BS_ButNoBS