Two ways to get legless

Credit: Robert Reisz

The evolutionary origins of the Amphisbaenia, a group of legless lizards adapted for burrowing, are controversial. Molecular evidence has placed them within lacertid lizards, whereas morphological evidence tends to unite them with snakes, with inheritance of the limbless, elongate body from a common ancestor. The discovery of a fossil limbed lizard from the famous Eocene Messel shales in Germany should settle the question. The new form seems to combine features of lacertids with those of amphisbaenians, supporting the first hypothesis and suggesting that limblessness in amphisbaenians evolved independently from that in snakes.