Squamata

From EvoWiki

Scaled reptiles

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Sauropsida
Order:	Squamata Oppel, 1811

Suborders

see text

Squamata (scaled reptiles) is the largest recent order of reptiles, 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 open their mouths very widely to accommodate comparatively large prey. The male members of the group Squamata are the only vertebrates with a hemipenis. This is also the only reptile group in which can be found both viviparous and ovoviviparous species, as well as the usual oviparous reptiles.

Classically, the order is divided into three suborders:

Lacertilia, the lizards;
Serpentes, the snakes;
Amphisbaenia, the worm lizards.

Of these, the lizards form a paraphyletic group. In newer classifications the name Sauria is used for reptiles and birds in general, and the Squamata are divided differently:

Suborder Iguania (the iguanas and chameleons)
Suborder Scleroglossa
- Infraorder Gekkota (the geckos)
- Infraorder Anguimorpha (the monitors, goannas, Komodo dragon, Gila monster, and slow-worms)
- Infraorder Scincomorpha (skinks, whiptail lizards and common European lizards)
- Infraorder Serpentes (the snakes)
- Infraorder Amphisbaenia

The exact relationships within these two suborders are not entirely certain yet, though recent research strongly suggests that several families form a venom clade which encompasses a majority (nearly 60%) of Squamate species.

The Squamata do not include the tuataras, New Zealand reptiles resembling lizards.

This page is a stub. You can help EvoWiki by expanding it into a full article. See this page for some ideas for how the page could look.