Legless lizard may refer to any of several groups of lizards that have independently lost limbs or reduced them to the point of being of no use in locomotion. It is the common name for the familyPygopodidae, but often refers to other groups, such as limbless anguids, depending on the region of the world. These lizards are often distinguishable from snakes on the basis of one or more of the following characteristics: possessing eyelids, possessing external ear openings, lack of broad belly scales, notched rather than forked tongue, having two more-or-less-equal lungs, and/or having a very long tail. Many families of lizards have independently evolvedlimblessness or greatly reduced limbs, including the following examples:
Anguidae – 102 species, of which 17 are limbless and in the generaOphisaurus, Pseudopus and Anguis from Eurasia and North America.
Cordylidae – an African family of 66 species, with one virtually legless genus Chamaesaura, containingfive species with hindlimbs reduced to small scaly protuberances.
Pygopodidae – all 44 species; they belong to the genera Aprasia, Delma, Lialis, Ophidiocephalus, Paradelma, Pletholax and Pygopus. All are endemic to Australia, except the two species of Lialis, which also occur in New Guinea, one of which is endemic to that island. Pygopodids are not strictly legless since, although they lack forelimbs, they possess hindlimbs that are greatly reduced to small digitless flaps, hence the often used common names of "flap-footed lizards" or "scaly-foot". The pygopodids are considered an advanced evolutionaryclade of the Gekkota, which also contains six families of geckos.
Dibamidae – all 23 species in the family, which comprises the monotypic Mexican genus Anelytropsis and the Southeast Asian genus Dibamus. All are limbless burrowers that are nearly or completely blind.
Gymnophthalmidae – a large neotropical family containing many species with reduced limbs, the most extreme being the 23 species in the genus Bachia, which escape by making sudden saltatory "figure-8" flicks with the body and tail.
Scincidae – commonly known as skinks, the largest lizard family with over 1500 species, of which many are limbless and nearly-limbless species, including the genera Acontias, Feylinia, Melanoseps, Paracontias and Typhlosaurus from Africa, Lerista from Australia, and some species in the genera Chalcides from southern Europe and North Africa, and Scelotes from southern Africa.
The 190 species of worm-lizards in the Amphisbaenia belong to a different suborder of the Squamata to the lizards and are not included here.
