Legless lizard
Legless lizard may refer to any of several groups of lizards which have independently lost limbs or reduced them to the point of being of no use in locomotion.[1] It is the common name for the family Pygopodidae,[2] but often refers to other groups, such as limbless anguids, depending upon the region of the world.[citation needed] 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, and/or a very long tail (while snakes have a long body and short tail).[1]
Many families of lizards have independently evolved limblessness or greatly reduced limbs (which are presumably non-functional in locomotion), including the following examples:[1]
- Anguidae – 73 species of which thirteen are limbless species, in the genera Ophisaurus, Pseudopus and Anguis from Eurasia and North America.
- Cordylidae – an African family of 66 species, with one virtually legless genus Chamaesaura, containing five species, with hindlimbs only, reduced to small scaly protuberances.
- Pygopodidae – all 44 species belonging 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 which are greatly reduced to small digitless flaps, hence the often used common names of "flap-footed lizards" or "scaly-foot".[2] The pygpodids are considered an advanced evolutionary clade of the Gekkota which also contains six families the geckos.
- Dibamidae – all 23 species in the family comprising the monotypic Mexican genus Anelytropsis and the Southeast Asian genus Dibamus. All are limbless burrowers which are nearly or completely blind.
- Anniellidae – comprising the single genus Anniella which contains six legless lizards that inhabit central / southern California and Baja California, Mexico.
- Gymnophthalmidae – a large neotropical family containing many species with reduced limbs, the most extreme being the 23 species in genus Bachia which escape by making sudden saltatory "figure-of-8" flicks with the body and tail.
- Scincidae – the largest lizard family with over 1500 species, of which many are limbless and nearly-limbless species, including (but not confined to) the genera Acontias, Feylinia, Melanoseps, Paracontias and Typhlosaurus from Africa, Lerista from Australia, and some species of 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.
See also
References
- ^ a b c Pough et al. 1992. Herpetology: Third Edition. Pearson Prentice Hall:Pearson Education, Inc., 2002.
- ^ a b Browne-Cooper, R., Bush, B., Maryan, B., Robinson, D. (2007). Reptiles and Frogs in the Bush: Southwestern Australia. University of Western Australia Press. pp. 243, 244. ISBN 978-1-920694-74-6.
{{cite book}}: Cite has empty unknown parameters:|chapterurl=and|month=(help)CS1 maint: multiple names: authors list (link)