Squamata (scaled reptiles) is the largest recent order of Lepidosauria, including lizards and snakes. 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 braincase. This is particularly visible in snakes, which are able to detach their jaws entirely to accommodate very large prey items. The male members of the group Squamata are the only vertebrates with a hemipenis. This is also the only reptile group where we can find both viviparous and ovoviviparous species, as well as the usual oviparous reptiles.
Most of the major squamate clades made their appearances in the Late Jurassic or Cretaceous, indicating major cladogenetic events must have ocurred even earlier. Their representation in earlier Mesozoic microvertebrate samples can therefore be expected, but whereas it may be relatively easy to diagnose a squamate as such, more specific identifications are rendered difficult by the generalized morphology of the early representatives.
Classically, the order is divided into two suborders:
Author: Koen Stein
Last updated: 21/11/2005
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