(This article is about the Squamata order of reptiles. For the Roman scale armour, see Lorica squamata.) The order Squamata, or the scaled reptiles, are the largest recent order of reptiles, comprising all lizards and snakes. With over 10,000 species, it is also the second-largest order of vertebrates, after the perciform fish. Members of the order are distinguished by their skins, which bear horny scales or shields. They also possess movable quadrate bones, making it possible to move the upper jaw relative to the neurocranium. This is particularly visible in snakes, which are able to open their mouths very wide to accommodate comparatively large prey. They are the most variably sized order of reptiles, ranging from the 16 mm (0.63 in) dwarf gecko (Sphaerodactylus ariasae) to the 5.21 m (1