Xenosauridae is a family of

anguimorph The Anguimorpha is a suborder of squamates. The group was named by Fürbringer in 1900 to include all autarchoglossans closer to '' Varanus'' and ''Anguis'' than ''Scincus''. These lizards, along with iguanians and snakes, constitute the propose ...

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

s whose only living representative is the

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

Xenosaurus ''Xenosaurus'' is a genus of lizards; it is the only extant genus in the family Xenosauridae, with 14 species currently recognized."Xenosauridae" and "''Xenosaurus'' ". The Reptile Database. www.reptile-database.org. Also known as knob-scaled li ...

'', which is native to Central America. Xenosauridae also includes the extinct genera ''

Exostinus ''Exostinus'' is an extinct genus of xenosaurid lizard from the Late Cretaceous to Oligocene of the western United States. It was named in 1873 by Edward Drinker Cope as ''Exostinus serratus'' for jaw and skull bones found in the White River For ...

'' and '' Restes''. Also known as knob-scaled lizards, they have rounded, bumpy scales and

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amph ...

s. Most living species prefer humid, rocky habitats, although they are widespread within their native regions, with some inhabiting semi-arid scrub environments. They are carnivorous or insectivorous, and give birth to live young. ''

Shinisaurus The Chinese crocodile lizard (''Shinisaurus crocodilurus'') is a semiaquatic anguimorph lizard found only in cool forests in southeastern China and northeastern Vietnam. The Chinese crocodile lizard spends much of its time in shallow water or in ...

'', the Chinese crocodile lizard, was once also regarded as a member of Xenosauridae, but most recent studies of the evolutionary relationships of anguimorphs consider ''Shinisaurus'' to be more closely related to

monitor lizard Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and West African Nile monitor, one species is also found in south America as an invasive species. A ...

s and helodermatids than to ''Xenosaurus''. Xenosauridae is part of a larger

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

or evolutionary grouping called

Carusioidea Carusioidea is a clade of lizards that includes the family Xenosauridae (knob-scaled lizards) from Central America and the extinct genus '' Carusia'' from the Late Cretaceous of Mongolia. It was named in 1998 after a sister-group relationship wa ...

, which, in addition to xenosaurids, includes the extinct genus ''

Carusia ''Carusia'' is an extinct genus of lizards from the Late Cretaceous of Mongolia. It is a close relative of the family Xenosauridae, which includes living knob-scaled lizards. Fossils of the type and only species ''Carusia intermedia'' come from ...

''. The oldest xenosaurids are known from the Cretaceous, including the Late Cretaceous of North America and Early Cretaceous of Asia.

References

External links

xenosauridae
Lizard families Taxa named by Edward Drinker Cope Extant Barremian first appearances {{lizard-stub es:Xenosauridae fr:Xenosauridae