Black and white lari seabirds flock along the tidemark on the silvery sand, pecking at the seaweed and the dead sea animals washed up and left by the ocean. Other more adventurous birds strut about in the dry sand near the fringe of curving palm trees at the head of the beach. They are being watched from the ridge of red granite that sweeps down from the hilly interior of the island and protrudes as a headland at one end of the beach. Suddenly, from the rounded rocks, a sleek green and orange shape darts out onto the dazzling sand and, in a burst and flurry of feathers, one of the more foolhardy birds is caught and killed. The hunter is a tiny megalosaur, similar to that found on the great island of Madagascar 1,000 kilometers (620 miles) to the south. It is only about 3 meters (10 feet) l