a couple of articles about prehistoric Madagascar

Chlidonias · 15 May 2015

first this one about a sinkhole full of skeletal remains of recently-extinct species:
Lemur Graveyard Discovered in Underwater Madagascar Cave

7 May 2015

An underwater cave in Madagascar has revealed hundreds of fossils from an extinct lemur, possibly washed into the underground trap by storms thousands of years ago.

The lemur graveyard also contained fossils from a suite of extinct animals, including primates, hippos, a crocodile and the island's largest predatory cat. The sinkhole where the bones were found may have preserved the fossils for a few thousand years, said Alfred Rosenberger, an physical anthropologist at Brooklyn College, City University of New York, who led the team.

"Pretty well preserved is an understatement," Rosenberger told Live Science. "The skulls and jaws are virtually complete and very often, even undamaged. So we'll pick up 12 skulls of one species and they'll all be absolutely perfect."

It's not clear exactly how the animals arrived in the watery grave, though one possibility is that the animals were swept underwater during a seasonal hurricane or a flash flood, Rosenberger said.

Sinkholes can often provide unprecedented views into the past, because the still, cold water protects bones from the ravages of bacteria, wind and waves, Rosenberger said. He and a team of cave divers were exploring underwater caves in the Dominican Republic when his lead diver, Phillip Lehman, got a tip about a sinkhole in Tsimanampetsotsa National Park, an arid region with seasonal storms in Madagascar whose limestone cliffs have been eaten away by water and wind over time, leaving a landscape of caves and tunnels resembling Swiss cheese.

To see what was inside, a group of cave divers traveled 82 feet (25 meters) below the water's surface into a vertical sinkhole called Aven (which means "sinkhole" in French). At the transition zone where the dimly lit water transitions to utter blackness, the team found hundreds of animal bones, from dozens of species.

Because cave diving is incredibly dangerous, requiring rigorous safety protocols, and scuba divers can only be underwater for a few hours, the team was not able to completely survey the fossils. But what they found was stunning.

Many of the fossils belonged to an extinct lemur, which the researchers have tentatively identified as Pachylemur insignis. Four fossils belonged to predatory cats, including the massive, extinct cat Cryptoprocta spelea. The oldest fossils in the cave came from animals that died a few thousand years ago, while others came from a still-living rodent that was introduced to the island by humans, Rosenberger said.

It's still a mystery how the animals came to rest there. Unlike in other caves, the animals, other than perhaps the crocodile, likely didn't deliberately enter the sinkhole, Rosenberger said.

Lemurs "don't live underground, they don't shelter underground. It's very unlikely that the enormous accumulation of bones could have been because the animals stumbled in there," Rosenberger said.

Instead, it's possible that a series of events, such as flash floods or typhoons, swept the animals away over time, Rosenberger said. The presence of stalagmites, which form from the constant drip-drip-drip of mineral-rich water from the ceiling to the floor of a cave, suggests the cave was once dry, or there wouldn't have been any floor on which the water could land, Rosenberger said. By dating the thorium and uranium isotopes, or elements with different numbers of neutrons, the researchers could determine when some of the flooding events occurred, the researchers report in their paper, which was published in the April issue of the Journal of Human Evolution.

Because many of the fossils have been found on researchers may soon be able to date the fossils, which could help them determine when some of these historic creatures went extinct

That could also shed light on one of the island's most pressing problems.

"We are losing the animals of Madagascar to extinction at an enormous rate," Rosenberger said.

Humans first colonized the island roughly 3,000 years ago, which may overlap with when some of these fossils were deposited, so the cave could help determine whether humans played a significant role in the islands' extinction crisis, Rosenberger said.
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The first page of the scientific paper can be seen here: Giant subfossil lemur graveyard discovered, submerged, in Madagascar

Chlidonias · 15 May 2015

and next a much-older subject (and a slightly older article), but one which could be interesting for anyone in or near New York:
CFZ: Daily News: This King-Size Frog Hopped With Dinosaurs

15 February 2010

Now appearing in the lobby of Stony Brook University Medical Center: a frog that lived in the era of the dinosaurs and is as big as a beach ball. Scientists believe it to be the largest frog ever.

The immense frog is part of a permanent exhibition that also features reconstructions of a vegetarian pug-nosed crocodile and a small meat-eating dinosaur.

“This was undoubtedly the heaviest frog ever, we estimate about 10 pounds,” said David Krause, the Stony Brook University paleontologist who unearthed the fossils of the frog and the other creatures in Madagascar. “It probably ate any available prey — lizards and snakes and mammals. It was large enough to maybe even eat hatchling dinosaurs.”

The frog’s scientific name is Beelzebufo ampinga, which means “armored devil toad.”

About 150 schoolchildren from public schools here on Long Island attended the unveiling of the exhibition last week — none of them as small as hatchlings, but small enough to find the frog impressive.

“Looks like he ate a human,” said one, pointing at the frog’s stomach.

The reconstruction of the creature, described as the “frog from hell” by the scientists who dug it up in Madagascar, portrays Beelzebufo as a grim-looking amphibian, with a large pink tongue and sand-colored skin to match its desert environment. It took 15 years and 75 fossils to put together an accurate reconstruction.

The frog lived about 65 million years ago, in a semi-arid environment that experienced sporadic heavy rains, said Dr. Krause, who analyzed sediments to deconstruct the frog’s living conditions. Dr. Krause and his colleagues believe that the frog is related to the Pac-Man frog, a modern-day species in South America that is named for the video game character.

Like the Pac-Man, Beelzebufo was probably an ambush predator, meaning it wriggled its rear end into the ground, sticking its head out, in anticipation of the oblivious lizard or snake.

The reconstruction on display is the only one of the devil frog that the researchers know of, and was made by Joe Groenke, a fossil technician, and Luci Betti-Nash, a scientific artist. Mr. Groenke created a cast of the frog’s head — essentially an enlarged version of the Pac-Man frog — and Ms. Betti-Nash sculpted the body with clay and painted it with water-based acrylics. The colors are a guess, based on where Beelzebufo lived and the coloration of modern desert amphibians.

The exhibit, financed by the Stony Brook University Medical Center Development Council, is intended not only to raise public awareness of science but also to draw attention to Dr. Krause’s side project — the Madagascar Ankizy Fund. The fund, which is a nonprofit, finances health clinics and schools in rural Madagascar.

“We get so much from these digs,” Dr. Krause said. “We get these phenomenal fossils; we have had many graduate students get their Ph.D.’s through this work. We were looking for ways to give back, and they really wanted their children to have an education.”
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a couple of articles about prehistoric Madagascar

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a couple of articles about prehistoric Madagascar

Chlidonias Moderator Staff Member 15+ year member

Chlidonias Moderator Staff Member 15+ year member

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