Washington, Nov 11 : Research has shown that several species of lizards have rapidly evolved an elongate, limbless body form, over geologically brief periods.
Adam Skinner of the University of Adelaide, and his colleagues, undertook the research.
The subject of their research was skinks, which are a common sight in Australia and many species have limbs that are either reduced or missing entirely.
According to Skinner, "It is believed that skinks are loosing their limbs because they spend most of their lives swimming through sand or soil; limbs are not only unnecessary for this, but may actually be a hindrance".
Skinner and his colleagues performed a genetic analysis of the lizards to investigate the pattern and rate of limb reduction, finding that evolution of a snake-like body form has occurred not only repeatedly, but also very rapidly and without any evidence of reversals.
"At the highest rate, complete loss of limbs is estimated to have occurred within 3.6 million years," Skinner said.
Compared to similarly dramatic evolutionary changes in other animals, this is blisteringly fast.