Snake
(IN PHOTO)A boa constrictor is seen at the National Institute of Biodiversity (INBio) in Santo Domingo de Heredia October 27, 2010. According to a press release of the United Nations (UN) Biodiversity Summit held in Nagoya, Japan, Costa Rica won the Future Policy Award 2010 in celebration of its biodiversity law as a milestone of excellence in meeting the goals of the UN Convention on biological diversity. REUTERS

A new research study has made a significant revelation on the evolution of snakes by claiming that the ancestor of the present-day snakes was a nocturnal, stealth-hunting predator with tiny hind limbs, along with ankles and toes. Although it is a known fact that snakes show incredible diversity with more than 3,400 living species found in a wide range of habitats, such as land, water and in trees, little is known about how, when and where they evolved and how their original ancestor looked and behaved.

The first comprehensive reconstruction of these ancestral snakes was made possible through analysis of fossils, genes and anatomy from 73 snakes done by researchers at Yale University. They established that the ancient snakes first originated on land in the Early Cretaceous period about 128 million years ago and hunted only at night. Their study is published in the journal BMC Evolutionary Biology.

Allison Hsiang, the study's lead researcher and a postdoctoral researcher of geology and geophysics at Yale University, says, “While snake origins have been debated for a long time, this is the first time these hypotheses have been tested thoroughly using cutting-edge methods. By analysing the genes, fossils and anatomy of 73 different snake and lizard species, both living and extinct, we've managed to generate the first comprehensive reconstruction of what the ancestral snake was like."

The study team is of the opinion that with their reconstruction model of the ancient snake, which is based on plethora of new, more complete fossils which were recently uncovered, will help settle at least two major "longstanding debates" about the origins of snakes. The co-author of the study, Daniel Field, says, "Our analyses suggest that the most recent common ancestor of all living snakes would have already lost its forelimbs, but would still have had tiny hind limbs, with complete ankles and toes. It would have first evolved on land, instead of in the sea."

He further adds that “The ancestors of snakes slithering around today were able to take advantage of the relatively empty landscape left behind by the dinosaurs. Like mammals, the early snakes found themselves living in a world where the dominant animals were suddenly no longer around, leaving tons of ecological niches open for the taking.”

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