Madagascar's buried treasure

Natural History, March, 1997 by Scott D. Sampson, David W. Krause, Catherine A. Forster

In recent years, evidence has demonstrated that birds are almost certainly the direct descendants of a group of theropod dinosaurs. In addition to several apparent bird characteristics--including bony bumps on the forearm for the attachment of flight feathers--this new Malagasy animal has a long, robust tail unfused bones in the upper portion of the foot, characteristics typically associated with dinosaurs. Most remarkable of all is a large, retractable, sicklelike claw on the second toe of its hind foot, a smaller but identical replica of the killing claws wielded by certain theropods such as Deinonychus and Velociraptor. Although geologically much younger than the famous Archaeopteryx, this bird can similarly be regarded as a missing link between dinosaurs and birds, providing further evidence that modern avians evolved from small theropods.

On our third trip, in 1996, we zeroed in on three new sites that showed promise for additional titanosaur material. Although none of these quarries surpassed the 1995 site in terms of titanosaur skeletons, one of them held yet another gem, one that all of us had secretly (and not so secretly) hoped for, but dared not expect. A series of theropod tail vertebrae led us to an exquisitely preserved lower jawbone of Majungasaurus, complete with thirteen gleaming, serrated teeth. Exclamations of tsara he (Malagasy for "big good") erupted as one skull bone after another was exposed to light for the first time in 75 million years. We eventually unearthed the complete skull of this enigmatic beast. Meanwhile, on the other side of the same hill, another prize was exhumed--the skull of a second, larger species of titanosaur, the first reasonably complete titanosaur skull known. In a matter of days, we had found the first two dinosaur skulls known from Madagascar, both of which are now back in the laboratory, being extracted from the entombing rock.

All told, our three expeditions have more than quadrupled the total number of species known from the Late Cretaceous of Madagascar. The tally of dinosaurs and birds so far includes eight different kinds, six of which were previously unknown and the remaining two of which were very poorly known. Perhaps most exciting is the vast, still untapped potential of the field area; numerous other sites with high concentrations of fossilized bone fragments are scattered,throughout the hills around Berivotra. We eagerly anticipate returning and combing those grassy hills for more signs of ancient treasure.

RELATED ARTICLE: Island Castaways

The fourth largest island on earth, Madagascar is separated from Africa by the Mozambique Channel, 240 miles across at its narrowest point and more than a mile deep in most places. Some 160 million years ago, Antarctica, South America, Africa, India, Australia, and Madagascar were joined together, forming the great southern supercontinent of Gondawana. Over millions of years, this supercontinent fragmented into the continental blocks we recognize today. According to recent geophysical models, Madagascar, India, Antarctica, and Australia split off from eastern Africa as a single tectonic unit sometime between 160 to 150 million years ago. Approximately 30 million years later, Madagascar and India separated as a unit from Antarctica and Australia. Finally, about 90 to 85 years ago, the Indian subcontinent broke away from Madagascar and began its glacially paced journey northward toward Asia. Madagascar has existed in virtual isolation ever since that time.