International Dinosaur Discoveries
How did the Majungatholus remains explain dinosaur migration from South America to Madagascar?
The Majungatholus was very similar to another dinosaur found in Argentina, although this animal had two horns. Other bone fragments found in India were also very similar, indicating these dinosaurs were all from the same group. However, no evidence has been found to date of any of these dinosaurs in Africa.
Approximately 120 million years ago, South America, Africa, Antarctica, Madagascar, Australia, and India were all joined together in one supercontinent called Gondwana, or Gondwanaland. Scientists originally believed a piece of the landmass containing South America and Africa first split away from Gondwanaland, then pulled apart to form the South Atlantic Ocean. As the breakup of Gondwanaland continued, Madagascar ended up as an island to the east of Africa. The discovery of Majungatholus, and its similarity to dinosaurs in India and South America, made this scenario unlikely. How could this group of dinosaurs get from South America to Madagascar without first going through Africa?
To answer this question, scientists modified the sequence by which Gondwanaland broke up. Now they believe the landmass of Africa broke off from Gondwanaland first, becoming isolated from the rest of the supercontinent. South America, and the Indian subcontinent, which included Madagascar, remained connected to Antarctica as recently as 80 million years ago by means of land bridges. The group of dinosaurs to which Majungatholus belonged, as well as many other dinosaurs, could have migrated freely from South America to India and Madagascar by way of Antarctica. This would account for the remains found in those continents, and also for the lack of them in Africa.