When the snake lost its limbs

2004/02/05 Elhuyar Zientzia

• Genetika
• Zoologia

Was it the first snake to live in the sea or on earth? Biologists have been trying to answer this question for some time. To find the definitive answer, extensive genetic research has been carried out, which, contrary to what many thought, caused the loss on land of the members of the ancestor of the snake.

For the research, 64 species of lizard and snakes have been taken, of which two genes have been analyzed. These lizard species represent the 19 surviving lizard families. That was essential, because the ancestor of the snake was the lizard. What they have determined is that this ancestor was from the family of terrestrial lizards or sea lizards.

When the snake separated from the branch of the lizards, the mosasaurus was the only lizard of the sea. As the mosasaurus has disappeared, they have taken as reference to their closest relative: Dragon of Komodo. And it seems that the dragon and the serpent of Komodo are not close relatives. Therefore, the conclusion is clear, if it was not sea, the ancestor of the snake that needed land.

The research has allowed the development of a family tree that shows the relationship between snake and lizard species.

In the picture: top left Tropidophis feicki and right Uromacer oxyrhyncus; bottom left Typhlops biminiensis and right Elaphe guttata.

(Photographer: S. Blair / Penn State).