Classification
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 (since "lizards" excludes the subclade of snakes). In newer classifications, the name Sauria is used for reptiles and birds in general, and the Squamata are divided differently:
- Suborder Iguania – (the agamids, chameleons, iguanids and other New World lizards)
- Suborder Scleroglossa
- Infraorder Anguimorpha – (the monitors, Gila monster, alligator lizards, galliwasps, slow worms and others)
- Infraorder Amphisbaenia – worm lizards
- Infraorder Gekkota – (the geckos)
- Infraorder Scincomorpha – (skinks, whiptail lizards and common European lizards)
- Infraorder Serpentes – (the snakes)
The relationships between these suborders is not yet certain, though recent research suggests several families may form a hypothetical venom clade which encompasses a majority (nearly 60%) of squamate species. Named Toxicofera, it combines the following groups from traditional classification:
- Suborder Serpentes (snakes)
- Suborder Iguania (agamids, chameleons, iguanids, etc.)
- Infraorder Anguimorpha, consisting of:
- Family Varanidae (monitor lizards, including the komodo dragon)
- Family Anguidae (alligator lizards, glass lizards, etc.)
- Family Helodermatidae (Gila monster and Mexican beaded lizard)
Read more about this topic: Squamata