Splitjaw Snake: Bolyeriidae

Also known as the Round Island casarea boa, the keel-scaled splitjaw lives only on Round Island, which is located in the Indian Ocean east of Madasgascar and just northwest of the island of Mauritius. At one time, this snake made its home on other small islands near Round Island and on the much-larger Mauritius, but now they live on just the one island. Round Island covers only 374 acres (151 hectares) and was created from lava ejected from a volcano. In the 1960s and 1970s, Round Island also had another species of splitjaw. During that period, observers on the island discovered a smooth-scaled splitjaw and watched the snake over a two-decade period. They were able to identify the snake from sighting to sighting by a distinctive scar on its body. They saw that lone snake on Round Island for the last time in 1975, and no one has ever seen a smooth-scaled splitjaw again. The discovery of the living snake was quite fortunate, because scientists would otherwise have never known of this species. While fossils of many other living and extinct snake species have been found, no one has ever found and identified a fossil from the smooth-scaled splitjaw.