Anguidae refers to a large and diverse family of lizards native to the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

. Common characteristics of this group include a reduced supratemporal arch, striations on the medial faces of tooth crowns, osteoderms, and a lateral fold in the skin of most taxa. The group includes the

slowworm The slow worm (''Anguis fragilis'') is a reptile native to western Eurasia. It is also called a deaf adder, a slowworm, a blindworm, or regionally, a long-cripple and hazelworm. These legless lizards are also sometimes called common slowworms. T ...

s, glass lizards, and

alligator lizards An alligator lizard is any one of various species of lizards in the family Anguidae that have some shared characteristics. The term may specifically refer to: Species of the genus ''Elgaria'': * Northern alligator lizard (''Elgaria coerulea'') ...

, among others. The family is divided into two subfamilies (Anguinae and Gerrhonotinae), and contains about 87 species in 8

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

Morphology and reproduction

Anguids have hard

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 amp ...

s beneath their scales giving them an armored appearance. Many of the species have reduced or absent limbs, giving them a

snake Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more ...

-like appearance, while others are fully limbed. Body type varies among species, with sizes ranging from 10 cm to 1.5 m. The group includes

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and m ...

and

viviparous Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the ...

species, both of which can be observed in a single genus at times.

Feeding and habitat

These lizards are known carnivorous or

insectivorous A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores were ...

foragers, feeding primarily on insects, although larger species have been known to feed on small reptiles and amphibians. They inhabit a wide range of different habitats across the globe, from arid to tropical environments. Most known species are terrestrial or semifossorial, with the exception of one arboreal genus: '' Abronia''.

Evolution

Anguids have a relatively good fossil record and are relatively common as fossils in the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

and

Paleogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

of western North America. The oldest known anguid, with the most complete fossil record of any lizard, is ''

Odaxosaurus ''Odaxosaurus'' is an extinct genus of anguid lizards that existed in western North America from the Late Cretaceous to the Paleocene. Fossils of the type species ''Odaxosaurus piger'' and the species ''O. priscus'' are widespread throughout ...

'', a member of the extinct anguid subfamily

Glyptosaurinae Glyptosaurinae is an extinct subfamily of anguid lizards that lived in the Northern Hemisphere during the Late Cretaceous and the Paleogene. Description Glyptosaurines are known primarily from their osteoderms, scale-like pieces of bone that ar ...

, from the late

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campani ...

of Canada, about 75 million years ago. ''Odaxosaurus'' and other Late Cretaceous anguids already exhibit many features found in living anguids, including chisel-like teeth and armor plates in the skin, suggesting a long evolutionary history for the group. Anguids were particularly diverse during the Paleocene and Eocene in North America; some species, such as those belonging to Glyptosaurinae, grew to large size and evolved a highly specialized crushing dentition. The long fossil record for the Anguidae in North America suggests that the group probably evolved in North America during the Cretaceous before dispersing to Europe in the Paleogene.

Classification

Family ANGUIDAE * Subfamily Anguinae ** Genus ''

Anguis SlowwormsThe "slow-" in slowworm is distinct from the English adjective ''slow'' ("not fast"); the word comes from Old English ''slāwyrm'', where ''slā-'' means "slowworm" and ''wyrm'' means "serpent, reptile". () (also called blindworms and ha ...

'' - slowworms (five species) ** Genus '' Dopasia'' - Asian glass lizards (seven species) ** Genus '' Hyalosaurus'' - North African glass lizard (one species) ** Genus ''

Ophisaurus ''Ophisaurus'' (from the Greek 'snake-lizard') is a genus of superficially snake-like lizards in the family Anguidae. Known as joint snakes, glass snakes, or glass lizards, they are so-named because their tails are easily broken; like many liz ...

'' - American glass lizards (five species) ** Genus ''

Pseudopus ''Pseudopus'' is a genus of anguid lizards that are native to Eurasia. One extant species remains, the sheltopusik, with four fossil species. They are the most robust members of subfamily Anguinae. The oldest fossils of the group date to the Earl ...

'' - scheltopusik (one extant species) * Subfamily Gerrhonotinae - alligator lizards ** Genus ''

Barisia ''Barisia'' is a genus of lizards in the family Anguidae. The genus is endemic to Mexico. Species The following species are recognized as being valid."''Barisia'' ". The Reptile Database. www.reptile-database.org. http://reptile-database.reptari ...

'' - alligator lizards (seven species) ** Genus ''

Gerrhonotus ''Gerrhonotus'' is a genus of anguid lizards that are commonly referred to as alligator lizards, due to a vague resemblance to an alligator. Along with glass lizards (''Ophisaurus'') and many other lizards, alligator lizards have the ability to ...

'' - alligator lizards (seven species) ** Genus '' Abronia'' - arboreal alligator lizards (37 species) ** Genus ''

Elgaria ''Elgaria'' is a genus of New World lizards in the family Anguidae. Their common name is western alligator lizards. Geographic range Species in the genus ''Elgaria'' are distributed in western North America, from Mexico to Canada. Species The ...

'' - western alligator lizards (seven species) *Subfamily †

Genetic evidence indicates that Diploglossinae lies outside the clade containing Anguinae, Gerrhonotinae, and the family Anniellidae, Therefore it has been placed in own separate family

Diploglossidae Diploglossidae is a family of anguimorph lizards native to the Americas, with most genera being endemic to Hispaniola. Most members of this family (aside from the legless genus '' Ophiodes'') are known as galliwasps. They were formerly considere ...

References

External links

List of species in the family Anguidae
from the

Reptile Database The Reptile Database is a scientific database that collects taxonomic information on all living reptile species (i.e. no fossil species such as dinosaurs). The database focuses on species (as opposed to higher ranks such as families) and has entrie ...

* http://animaldiversity.org/accounts/Anguidae/ {{Taxonbar, from=Q191059 Anguids Taxa named by John Edward Gray Lizard families Extant Campanian first appearances