Spade-Headed Wormlizards: Trogonophidae

At first glance, the spade-headed wormlizards look like big earthworms. Just as earthworms have rings around their bodies, these wormlizards have thin rings from the back of the head to the tip of the tail. Such rings are called annuli (ANN-youlie). In the spade-headed wormlizards, the rings are made of tiny square-shaped scales that are the same size and shape from the belly to the back. Also like earthworms, the wormlizards have no legs. Wormlizards, however, do still have tiny leftover hip and shoulder bones inside their bodies.

The heads of spade-headed wormlizards are shaped like shovels, or spades, which gives them their name. Sometimes, people also call them by another common name, short-headed wormlizards, because their heads are quite small and end quickly after the neck. The edges of the face are quite sharp, providing an excellent digging tool for these burrowing animals. The body is flattened into an upside down "U" shape, so that the wormlizard has a rounded back and an inward-curved belly side. It has a very short, sometimes ridged, or keeled, tail. The tail begins at the vent, a slit-like opening on the underside of the animal.

Some spade-headed wormlizards are patterned with checks and spots. They are rather small animals, with adults ranging from 3.1 to 9.4 inches (8 to 24 centimeters) in length.