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| OU faculty member Lawernce Witmer will study Majungatholus atopus using this fiberglass cast of the dinosaur's skull. Photo: Rick Fatica |
Scientists' discovery in Madagascar off the coast of Africa of the remains of Majungatholus atopus -- a large predatory dinosaur whose family previously was found only in South America and India -- helps support a new theory about how the Earth's continents split millions of years ago.
The discovery was reported in the May 15 issue of the journal Science by researchers from the New York Institute of Technology, Ohio University, the State University of New York at Stony Brook, the University of Pennsylvania, and the Universite d'Antananarivo in Madagascar.
Scientists recovered pieces of the animal's tail and a near-complete skull during a 1996 expedition. Although the skull bones were scattered over a 2-meter area, they were remarkably well-preserved, says La wrence Witmer, an assistant professor of anatomy in Ohio University's College of Osteopathic Medicine and co-author of the study. Witmer is studying fiberglass casts of the fossils and working with the study's lead author, Scott Sampson, an assistant professor of anatomy at the New York College of Osteopathic Medicine of New York Institute of Technology. Scientists are particularly interested in the animal's strong resemblance to a horned ther opod called Carnotaurus, known only from Argentina. Both Majungatholus and Carnotaurus belong to the dinosaur family Abelisauridae, which lived during the Late Cretaceous period. Previously, members of this family have been found only in India and South America.
The occurrence of such closely related dinosaurs on widely separated landmasses supports a new hypothesis for plate tectonics -- the theory that landmasses shift their relative positions as they move slowly across the face of the Earth.
"Dinosaurs lived at a time when all of the continents were connected, so we can use them to test hypotheses about the timing of the breakup of the Earth's continents," Sampson says. "Until now, people assumed continents split in a particular pattern, which included South America and Africa breaking away as one unit.
"If that is the case, we would expect the animals in South America and Africa to be more closely related. But this animal found in M adagascar -- an island off the southeast coast of Africa -- is more closely related to animals found halfway around the world."
