The very early four-legged land vertebrates, such as Acanthostega and Ichthyostega, that dragged themselves from the muddy waters on to land had five, six, seven, even eight fingers.
The hand, which is said to be a "feat of microscale mechanical systems (MEMS), " measures just one millimeter across when closed into a fist, features four "fingers" made of six silicon wafers each, and touts four gas-powered balloons acting as the muscles at the wafers' joints.