Lizard heads called the parietal eye, a basal ("primitive") feature also present in the tuatara. This "eye" has only a rudimentary retina and lens and cannot form images, but is sensitive to changes in light and dark and can detect movement. This helps them detect predators stalking it from above. Until 2006 it was thought that among lizards, only the Gila monster and the Mexican beaded lizard were venomous. However, several species of monitor lizards, including the Komodo dragon, produce powerful venom in their oral glands. Lace monitor venom, for instance, causes swift loss of consciousness and extensive bleeding through its
Pyrenean rock lizard Pyrenean rock lizard The Pyrenean rock lizard (Iberolacerta bonnali ) is a species of lizards in the family Lacertidae. It is endemic to the Pyrenees where it occurs at high altitudes and is only active in summer. The specific name, "bonnali", is in honor of the Count of Bonnal who collected amphibians and reptiles while living at Montgaillard, Hautes-Pyrénées. The Aran rock lizard was initially included here as a subspecies, "Iberolacerta bonnali aranica", but is now considered a distinct species, "Iberolacerta aranica". The Pyrenean rock lizard is a large lizard growing to a snout-to-vent length of with a tail about