Episode 1 Field Guide: Finding fossils in Madagascar
This is the visual accompaniment to the Past Time podcast “Episode 1: Finding fossils in Madagascar”. The easiest way to listen to the podcast is to subscribe through iTunes by clicking on the purple podcast symbol on the right or by searching “Past Time” through the iTunes store and subscribing. If you don’t have iTunes, you can listen through your web browser by clicking here or by downloading the audio file from here. For pictures of the dinosaurs, crocs, and terrifying frog, click below to continue reading…
Below are some quick links for further information on the places and animals we mention in the episode. After the links are photos, maps, and diagrams with a little more context and background on the material we discuss in the episode. Enjoy!
People: Dr. Dave Krause
Dr. Dave Krause, a Distinguished Service Professor in the Department of Anatomical Sciences at Stony Brook University, talked to us about his fieldwork in the Late Cretaceous Rocks of Madagascar. This photo was taken while Dr. Krause was addressing the community of Berivotra, a small village near the larger city of Mahajanga on the northern coast of Madagascar, during the opening of a new research facility near the fossil site he and his team have been working at since 1993.
The field project began when Dr. Krause read an obscure report of a few scrappy fossils found by a French solider in 1895. Today, Dr. Krause leads a field team in collaboration with Stony Brook University and the University of Antananarivo (a university located in the capital of Madagascar). The excavations and research fueled by the fossil specimens have drawn hundreds of scientists together to work on the Late Cretaceous dinosaurs, crocodiles, snakes, and amphibians that have been found near Mahajanga and Berivotra.
Continue on and learn about where Dr. Krause and his team found their fossils and what kinds of amazing animals they coaxed from the ground. But first…
Madagascar is the fourth-largest island in the world. It’s twice the size of Great Britain or a little smaller than the state of Texas. It’s separated from the southeastern coast of Africa by the Mozambique Channel. A deep, fast flowing current flows through the channel making it tough to get from Africa to Madagascar by water. With a difficult-to-cross barrier to the west, the few animals that made it to the Island diversified like crazy. Today, many species of plants and animals are only found in Madagascar. The question becomes, have those plants and animals been stuck on Madagascar since it separated from Africa during the time of the dinosaurs, or did they cross the channel after the dinosaurs went extinct?
Way back 200 million years ago, the continents were linked in a supercontinent called Pangea. Then Pangea broke in half. Geologists call the southern part of broken-Pangea Gondwana. Gondwana was made up of South America, Africa, Australia, Antarctica, and India. Then Gondwana broke apart. Scientists are still trying to sort out the details of all the continents going their seperate ways, but we do know Madagascar and India broke off from Africa together about 115 million years ago, then India and Madagascar broke apart from each other 88 million years ago. This is all still during the Mesozoic Era, the Age of Dinosaurs. Madagascar stayed isolated in the Indian Ocean while India drifted north to slam into Asia. This crash of continents created the Himalayan Mountains.
The island of Madagascar may be a lot smaller than it’s closest neighbor, Africa, but it has nearly every environment you would expect to find on a much larger landmass. There are spiny deserts in the southwest, lush tropical rainforests in the east, green, rolling highlands in the central region and dry tropical forests in the north.
The first reports of fossils from Madagascar came from a French soldier who was camped on the prairie near the town of Berivotra, a little bit south of the coastal city of Mahajanga where the French Army had started their march on the capital city of Antananarivo.
Dr. Krause and his team made it to Berivotra by flying to Antananarivo then driving the 300 miles (500 km) north to the small-village. The trip used to take several days of driving, but now, thanks to new roads, it only takes about 7 hours to go from the capital to the fossil sites.
But why dig in Madagascar? To figure out where the weird animals came from!
The Modern Animals of Madagascar are weird.
Lemurs are a family of primates that are only found in Madagascar. Their closest relatives are lorises, a group of nocturnal primates from Africa and Southeast Asia. Lemurs are distant cousins of monkeys and apes (which includes us). Lemurs have been in Madagascar for a long time, but when exactly they arrived and what the earliest ancestor of the 100 modern lemur species looked like is still a mystery. Dr. Krause wanted to find out if there was any evidence that the earliest relatives of the lemurs were climbing around Madagascar during the last part of the Age of Dinosaurs, called the Late Cretaceous Period (about 66 million years ago).
Dr. Krause and his team didn’t limit their hunt to the the origins of lemurs, though. There are plenty of reptiles, birds, insects, and plants that are only found on the island of Madagascar. The only way to track down the origins of all these strange species was to find rocks that preserved their fossilized ancestors.
They found rocks with fossils, but the animals they found in them were as strange as the modern residents of Madagascar…
The Extinct Animals of Madagascar are Weirder!
Many of the fossils found in the Berivotra area are from a section of rock called the Maevarano Formation. The fossils preserved in the light-colored sandstone of the Maevarano are in beautiful shape. The dinosaurs and crocodiles are known from nearly-complete skulls and skeletons, a rare occurrence in paleontology. The top of the food chain in Madagascar 66 million years ago was occupied by:
Majungasaurus was a meat-eating dinosaur that belonged to a family of dinosaurs called Abelisauridae. The relatives of Majungasaurus, the abelisaurids, are found in sites in the Southern Hemisphere and India, fragments of the supercontinent Gondwana. Majungasaurus wasn’t the largest meat-eating dinosaur to stomp the planet, but his finely serrated teeth, blunted snout, single horn on the top of its skull, and flipper-like arms would have made it one of the strangest. Until you saw…
Masiakasaurus is the wolf-sized meat-eating dinosaur that reeled Adam back into paleontology. Adam’s silhouette is pointing to the forward-facing teeth that give Masiakasaurus (pronounced “Muh-she-ka-saurus”) an especially odd profile. What this animal did with those snaggle-teeth is tough to figure out. Some scientists have suggested they would have been useful for snapping up fish, but that’s just one hypothesis. Like Majungasaurus, the closest relatives of Masiakasaurus (which means “fierce” or “spicy” in Malagasy) are from South America. More fossils and geological research are necessary to tackle the details of the origins and movements of this fierce dinosaur’s ancestors.
Rapetosaurus krausei is named for a legendary giant king from Madagascar. The species “krausei” is named in honor of Dr. Krause for all of his work on the fossils from the area Rapetosaurus was found. The long neck, small head, and column-like legs are evidence Rapetosaurus was a sauropod dinosaur. Rapetosaurus was huge, the size of an elephant, but some of its relatives reached whale-like proportions and would have made Rapetosaurus look puny. If you want to learn more about sauropods, we’ll be talking to sauropod researcher Dr. Mike D’Emic in a few weeks about the biology of these giants.
When Rahonavis ostromi was first described in 1998, the scars along its arm-bones indicating flight feathers and light hollow bones were interpreted as evidence that this was a very primitive bird. As more fossils have been found, the features that make Rahonavis a “definite” bird actually turn out to be common in many dromeosaur dinosaurs such as Velociraptor. Rahonavis also shares the large, recurved toe-claw with dromeosaurs. The line separating dinosaurs and birds gets more blurry as more fossils are found and where Rahonavis perches in the dino-bird family tree is still an area of active research. The species ostromi is named in honor of Dr. John Ostrom, a Yale paleontologist who championed the connection between birds and dinosaurs in the 1960’s. If you’re interested in the connection between dinosaurs and birds, be sure to catch our second episode of Past Time when we talk to Dr. Alan Turner about his work on the dino-bird family tree.
Sixty-six million years ago in the Late Cretaceous (the end of the Age of Dinosaurs) Northern Madagascar was home to a stunning diversity of crocodiles. There were some that would have looked familiar with body plans similar to the modern crocodile, alligator, and fish-eating gharial. But others, like the hippo-or-toilet-bowl-headed croc Mahajangasuchus look nothing like any crocodile lurking in the water today.
Modern crocodiles and alligators are semi-aquatic animals, but it’s kind of an evolutionary accident that they’re all tied to the water. In the past, there were many terrestrial, or land-based, crocodiles. In Madagascar, the coyote-like Araripesuchus tsangatsangana would have pursued small prey on long legs built for running, not swimming. Close relatives of the Malagasy species of Araripesuchus have been found in South America and Africa, evidence of the ancient connection between the island and these two large continents.
Also on land, scurrying around with Araripesuchus, was one of the strangest crocodilians ever found: Simosuchus. Almost every other croc-relative, living or extinct, gets (or got) by by eating other animals. But Simosuchus has a squared-off snout (“Simo” means “pug-nosed” in Greek and “suchus” means crocodile) and leaf-shaped teeth that are very similar to plant-eating iguana’s teeth. Simosuchus was a squat, terrier-sized, plant-eating crocodile! Then to top off the weirdness, Simosuchus was covered in armor like an armadillo. Simo may have needed that armor, if it shared the environment with…
Beezlebufo means “Devil toad” a reference to the terrifying size of the animal and the duel horns it sported on its head. Its bones are rippled and pitted with a rough texturing, making the bones of the giant “Frog from Hell” easy to identify. Frogs and toads tend to be carnivorous and willing to eat most things they can get their mouths around. Because most frogs and toads we’re familiar with are small, we think of them as insectivorous, or bug-eating. But some toads are large enough to go for bigger prey. South America horned frogs – also called “Pac Man frogs” – eat rodents that are practically the size of the frog doing the eating. Beezlebufo could have also gone for prey close to its own size. In its environment this would have included small dinosaurs and crocodiles. Yes, Beezlebufo may have been a dinosaur-eating frog.
So, Berivotra was weird (and dangerous) 66 million years ago. What does it look like today?
The village of Berivotra sits on a rolling plain where small outcrops of sandstone poke out through the grass. Each day the field team hikes to a fossil quarry where they slowly excavate fossils or they go prospecting, searching for new fossil sites by walking with heads down in search of gleaming teeth or bone fragments.
The fossils aren’t just sitting on the surface waiting to be scooped up by paleontologists like Dr. Krause. Once a promising outcrop has been identified with fragmented pieces of bone and teeth, the careful excavation of the outcrop begins. By excavating into the hills, the team has found beautifully preserved fossils of the dinosaurs and crocodiles just below the surface. Once the outcrop has been identified, there are a few steps to follow…
Step 1) Most of the rock around the fossil is cleared way using dental picks and brushes but a halo of rock is left around the fossil. The surrounding rock stabilizes the fossil. The fossils+rock are left as pedestals (step 2) that are wrapped in toilet paper, then burlap and plaster. Now there is rock, plaster, fabric, and paper to hold the fossil together for (Step 4) when the boulder must be carried away. Because the excavation site is in a hilly area with steep ravines, the blocks must be hauled out by hand to the road where they can be transported back to the University of Antananarivo or exported to Stony Brook University where the fossils will be removed from the plaster and rock under controlled conditions. This careful lab excavation is called “preparation.” Once the fossils are cleaned and stabilized, they can finally be studied by paleontologists.
So what does it all mean?
The mission was to find the ancestors of the strange animals that live in Madagascar today. So far, the excavations lead by Dr. Krause indicate the lemurs, chameleons, and tenrecs didn’t make it to the island before the extinction of the dinosaurs 65.5 million years ago. Instead of lemurs, Dr. Krause found equally strange animals like Simosuchus and Masiakasaurus. In one important way, Late Cretaceous Madagascar was similar to Modern Madagascar: it was home to animals that have only been found on the island. Even compared to the dinosaurs and crocodiles known from Africa and South America Madagascar was a strange place, cut off from the evolutionary pressures that were shaping animals on other, larger landmasses.
Now, the hunt continues for fossils of the first lemurs to arrive in Madagascar, and a new hunt is on to figure out when the strange crocodiles and dinosaurs arrived and where their ancestors came from. Dr. Krause and his team will continue to explore the unexpected diversity and anatomy of the ancient animals of Madagascar.
Dinosaurs were there before, but who’s there now?
The village of Berivotra is occupied by several Malagasy farmers who herd goats, sheep, and cows. They also cultivate corn and care for chickens. Everybody speaks Malagasy and many speak French.
The children in the area used to gather to watch the paleontologists dig. When Dr. Krause asked why they didn’t have a school to attend, they said the teacher hadn’t been paid and left. Berivotra, like many rural areas in Madagascar is very poor and couldn’t afford to keep a school maintained. Madagascar itself is one of the poorest countries in the world and couldn’t support the education of children in such a remote area. So, Dr. Krause started the Ankizy Fund, a non-profit organization that builds schools and supports the teachers who work at them. The Ankizy Fund (“ankizy” means “children” in Malagasy) also brings medical and dental missions into rural communities around Madagascar, including the village of Berivotra.
Further sources of information on the animals of Madagascar for a general audience:
Wildlife of Gondwana by Patricia Vickers-Rich and Thomas H. Rich (1999)
The Natural History of Madagascar by Steven M. Goodman and Jonathan P. Bernstead (2007)
Mammals of Madagascar: A Complete Guide by Nick Garbutt (2007)
Citations from the scientific literature that get into the technical details of fossil exploration in Madagascar:
Samonds Karen E., Laurie R. Godfrey, Jason R. Ali, Steven M. Goodman, Miguel Vences, Michael R. Sutherland, Mitchell T. Irwin, and David W. Krause (2013) Imperfect Isolation: Factors and Filters Shaping Madagascar’s Extant Vertebrate Fauna. PLoS ONE 8(4): e62086. doi:10.1371/journal.pone.0062086
Krause David W., Scott D. Sampson SD, Matthew T. Carrano and Patrick M. O’Connor (2007) Overview of the history of discovery, taxonomy, phylogeny, and biogeography of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology 27(2): 1-20.
Forster, Catherine A., Scott D. Sampson, Luis M. Chiappe, and David W. Krause (1998) The Theropod ancestry of birds: New evidence from the Late Cretaceous of Madagascar. Science 279(5358): 1915-1919.