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Lizards

Lacertilia

Lizards are a widespread group of squamate reptiles, with more than 7,000 species, that are not snakes (and, depending on usage, may or may not include other limbless squamates such as worm lizards).  Lizards live on every continent except Antarctica and inhabit a wide range of environments; many groups are also widespread on islands. Many lizards are four-limbed and have movable eyelids and external ear openings, traits that usually help distinguish them from snakes. However, there are many exceptions: some lizards are legless, some have lost movable eyelids, and some lack external ear openings, so no single external feature identifies all lizards. Because snakes evolved from within the broader radiation traditionally called “lizards,” “lizard” is not a single natural (monophyletic) group in modern classification; it is largely defined by excluding snakes rather than by a unique shared feature.

Lizards are a widespread group of squamate reptiles, with more than 7,000 species, that are not snakes (and, depending on usage, may or may not include other limbless squamates such as worm lizards).  Lizards live on every continent except Antarctica and inhabit a wide range of environments; many groups are also widespread on islands. Many lizards are four-limbed and have movable eyelids and external ear openings, traits that usually help distinguish them from snakes. However, there are many exceptions: some lizards are legless, some have lost movable eyelids, and some lack external ear openings, so no single external feature identifies all lizards. Because snakes evolved from within the broader radiation traditionally called “lizards,” “lizard” is not a single natural (monophyletic) group in modern classification; it is largely defined by excluding snakes rather than by a unique shared feature.