New research conducted at Yale University and published in the Journal BMC Evolutionary Biology suggests that the first snakes evolved on land and not in the sea as was previously thought. According to researchers snakes evolved separately on the Northern supercontinent Laurasia and its Southern neighbor Gondwona land, approximately 128 million years ago, about a third of the way through the Cretaceous period.
This research suggests that the overall characteristics of these early snakes are broadly similar to those which live today. However, the early snakes still possessed miniscule limbs with appendages, that is toes. The research team asserts that these traits were inherited from a nocturnal predator organism which lived in dense vegetation. According to the scientists involved the first snakes evolved in Laurasia approximately 128 million years ago with those in Gondwona land following some 20 million years later.
We know that approximately 3,500 snake species exist today and they are present almost all temperate and tropical habitats. Hitherto very little was known about snake evolution as such this research is certain to precipitate further study. Of profound interest will be to establish the exact behavior of the common ancestral snake mentioned above. The scientists have managed to present a detailed model of the appearance and characteristics of the common ancestor.
The evolutionary origins of snakes have been the subject of debate for many years. This research is the first of its kind in that it tests the hypotheses presented in such debates. The research presents a detailed time line of snake evolution in both Gondwona land and Laurasia. This period of evolution dovetails with a proliferation of both bird and mammalian species. The early snakes are believed to have preyed on vertebrate and invertebrate species that were generally larger than themselves.
These early snakes had not evolved the ability to constrict and so larger prey animals were temporarily saved from this grisly form of dispatch. In contrast to other reptiles the first snakes are thought to have been primarily nocturnal. The first Diurnal (daytime) snakes are generally accepted to have appeared approximately 50 million years ago.
These new findings add weight to the evolutionary success of snakes which are recognized as being highly efficient disperser organisms.