Editing Lizard (section)

=== Distinguishing features ===
[[File:Mediterranean house gecko1.jpg|thumb|right|A young [[Mediterranean house gecko]] in the process of [[moulting]].|300px]]
Lizards typically have rounded torsos, elevated heads on short necks, four limbs and long tails, although some are legless.<ref>{{cite book|editor=McDiarmid, Roy W.|display-editors=etal |title=Reptile Biodiversity: Standard Methods for Inventory and Monitoring|year=2012|contribution=Reptile Diversity and Natural History: An Overview|author=McDiarmid, Roy W.|page=13|publisher=University of California Press |isbn=978-0520266711}}</ref> Lizards and snakes share a movable [[quadrate bone]], distinguishing them from the [[rhynchocephalia]]ns, which have more rigid [[diapsid]] [[skull]]s.<ref name =Jonesetal2011>{{cite journal| author=Jones| display-authors=etal| title=Hard tissue anatomy of the cranial joints in Sphenodon (Rhynchocephalia): sutures, kinesis, and skull mechanics| journal=Palaeontologia Electronica| date=2011| volume=14(2, 17A)| pages=1–92| url=https://palaeo-electronica.org/2011_2/251/index.html| access-date=2019-02-04| archive-date=2012-11-29| archive-url=https://web.archive.org/web/20121129115710/https://palaeo-electronica.org/2011_2/251/index.html| url-status=live}}</ref> Some lizards such as chameleons have [[prehensile]] tails, assisting them in climbing among vegetation.<ref name=Firefly/>

As in other reptiles, the skin of lizards is covered in overlapping [[Scale (anatomy)|scales]] made of [[keratin]]. This provides protection from the environment and reduces water loss through evaporation. This adaptation enables lizards to thrive in some of the driest deserts on earth. The skin is tough and leathery, and is shed (sloughed) as the animal grows. Unlike snakes which shed the skin in a single piece, lizards slough their skin in several pieces. The scales may be modified into spines for display or protection, and some species have bone [[osteoderm]]s underneath the scales.<ref name=Firefly/><ref>{{cite book|author1=Starr, C. |author2=Taggart, R. |author3=Evers, C. |year=2012|title=Biology: The Unity and Diversity of Life|publisher=Cengage Learning|page=429|isbn=978-1111425692}}</ref>

[[File:Red Tegu Skull.jpg|thumb|Red tegu (''[[Tupinambis rufescens]]'') skull, showing teeth of differing types]]

The dentitions of lizards reflect their wide range of diets, including carnivorous, insectivorous, omnivorous, herbivorous, nectivorous, and molluscivorous. Species typically have uniform teeth suited to their diet, but several species have variable teeth, such as cutting teeth in the front of the jaws and crushing teeth in the rear. Most species are [[pleurodont]], though agamids and chameleons are [[acrodont]].<ref name="Pou92">{{cite book |author=Pough|display-authors=etal|orig-year=1992 |title=Herpetology |edition=Third |publisher=Pearson Prentice Hall |date=2002 }}</ref><ref name=Firefly/>

The tongue can be extended outside the mouth, and is often long. In the beaded lizards, whiptails and monitor lizards, the tongue is forked and used mainly or exclusively to sense the environment, continually flicking out to sample the environment, and back to transfer molecules to the vomeronasal organ responsible for chemosensation, analogous to but different from smell or taste. In geckos, the tongue is used to lick the eyes clean: they have no eyelids. Chameleons have very long sticky tongues which can be extended rapidly to catch their insect prey.<ref name=Firefly/>

Three lineages, the [[gecko]]s, [[anole]]s, and [[chameleon]]s, have [[Gecko#Adhesion ability|modified the scales under their toes to form adhesive pads]], highly prominent in the first two groups. The pads are composed of millions of tiny setae (hair-like structures) which fit closely to the substrate to adhere using [[van der Waals force]]s; no liquid adhesive is needed.<ref name=Spinner2014>{{cite journal |last1=Spinner |first1=Marlene|display-authors=etal|title=Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness |journal=Scientific Reports |date=2014 |volume=4 |pages=5481 |doi=10.1038/srep05481 |pmid=24970387 |pmc=4073164 |bibcode=2014NatSR...4.5481S }}</ref> In addition, the toes of chameleons are divided into two opposed groups on each foot ([[zygodactyly]]), enabling them to perch on branches as birds do.{{efn|Chameleon forefeet have groups composed of 3 inner and 2 outer digits; the hindfeet have groups of 2 inner and 3 outer digits.<ref name=Firefly/>}}<ref name=Firefly/>