Squamata (order)

Order of reptiles distinguished by the horny scales or shields on the skin, either egg-laying or with live births, having movable quadrate bones making it possible to move the upper jaw relative to the braincase, and a male hemipenis, which is unique among vertebrates. Dating from the Upper Jurassic to present, represented by approximately 7,900 living species of lizards, snakes, and amphisbaenid "worm-lizards."