This is a list of the extant lizard families. Lizards are an

informal Formal, formality, informal or informality imply the complying with, or not complying with, some set of requirements (forms, in Ancient Greek). They may refer to: Dress code and events * Formal wear, attire for formal events * Semi-formal attir ...

group of

squamates Squamata (, Latin ''squamatus'', 'scaly, having scales') is the largest order of reptiles, comprising lizards, snakes, and amphisbaenians (worm lizards), which are collectively known as squamates or scaled reptiles. With over 10,900 species, it ...

Taxonomy

There are five

infraorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

s which separate the lizards, these are: Diploglossa,

Gekkota Geckos are small, mostly carnivorous lizards that have a wide distribution, found on every continent except Antarctica. Belonging to the infraorder Gekkota, geckos are found in warm climates throughout the world. They range from . Geckos ar ...

Iguania Iguania is an infraorder of squamate reptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed ...

Platynota Platynota is a polyphyletic group of anguimorph lizards and thus belongs to the order Squamata of the class Reptilia. Since it was named in 1839, it has included several groups, including monitor lizards, snakes, mosasaurs, and helodermatids. ...

and

Scincomorpha Scincomorpha is an infraorder and clade of lizards including skinks (Scincidae) and their close relatives. These include the living families Cordylidae (girdled lizards), Gerrhosauridae (plated lizards), and Xantusiidae (night lizards), as well ...

. This separation is based mainly on morphological similarities between family groups. The Diploglossans and Platynotans are two closely related infraorders which are very diverse families. Very few generalisations can be placed upon these families morphologically. Many species are limbless, while others have fully formed limbs. It is believed that these lizards are the closest lizard relation to the snakes. The Gekkotans are the second most diverse group of lizards. They can be morphologically distinguished by the absence of temporal arches, which allows greater moveability of the head. Most species also have cloacal sacs and fixed eyelids. The Iguanians are another diverse group of lizards. All iguanians are fully limbed. Most species ambush their prey, capture it with their tongue and have skin modification, such as crests and fans, used for many different reasons. The Scincomorphs are the most diverse group of lizards, accounting for almost half the species of lizards. The major distinguishing morphological feature of the Scincomorphs, is the presence of unsocketed teeth on the inner face of the jaw bones. They also lack the skin modifications present in many of the iguanians. This family contains varying degrees of limb reduction, from completely formed limbs to completely absent of limbs. As with most taxonomic classifications, there are many different interpretations of the evolutionary relationships. These include moving of families to different infraorders, merging or splitting of the infraorders and merging and splitting of the families.

References

* * {{cite web, title=Tropiduridae , url=http://www.embl-heidelberg.de/~uetz/families/Tropiduridae.html , accessdate=2006-05-30 , archiveurl=https://web.archive.org/web/20060418155828/http://www.embl-heidelberg.de/~uetz/families/Tropiduridae.html , archivedate=2006-04-18 , url-status=dead * Lacertilia Lacertilia