iPedia Free Information Center

Information about Lizards

Lizard
Fossil range: Jurassic - Recent
Enlarge picture
"Lacertilia", from Ernst Haeckel's Artforms of Nature, 1904

"Lacertilia", from Ernst Haeckel's Artforms of Nature, 1904
Scientific classification
Kingdom:Animalia
Phylum:Chordata
Superclass:Tetrapoda
Class:Sauropsida
Order:Squamata
Suborder:Lacertilia*
Günther, 1867
Families


Many, see text.


Lizards are reptiles of the order Squamata, normally possessing four legs, external ear openings and movable eyelids. The adult length of species within the order range from a few centimeters (some Caribbean geckos) to nearly three meters (Komodo Dragons).

Description

Enlarge picture
Lizard missing its tail.
Lizards are reptilian, four-legged, cold-blooded, with an integumentary system comprising scales, with a skull composed of quadrate bones. Lizards also possess external ears and movable eyelids. Encompassing forty families, there is tremendous variety in color, appearance and size. Due to their smooth, shiny appearance, lizards can appear slimy or slippery; their skin is actually very dry due to a lack of pores to excrete water and oils.

Lizards have scales on their skin which may be tubercular or have ossified encrustations called osteoderms.[1]

Most lizards are oviparous, though a few species are viviparous. Many are also capable of regeneration of lost limbs or tails.

Some lizard species, including the glass lizard and legless lizards, have some vestigial structures though no functional legs. They are distinguished from true snakes by the presence of eyelids and ears and a tail that can sometimes break off as a physical defense mechanism. Many lizards are good climbers or fast sprinters. Some can run bipedally, such as the collared lizard and the world's fastest lizard, the spiny-tailed iguana in the genus Ctenosaura.

Many lizards can change color in response to their environments or in times of stress. The most familiar example is the chameleon, but more subtle color changes occur in other lizard species as well (most notably the anole, also known as the "American chameleon," "house chameleon" or "chamele").

Diet

Lizards feed on a wide variety of foods including fruits and vegetation, insects, small tetrapods, carrion and even (in the cases of large predator lizards) large prey such as deer.

Venomous Lizards

Only two lizard species have proven to be venomous: the Mexican beaded lizard and the closely-related Gila monster, both of which live in northern Mexico and the southwest United States. Even though there are myths and legends abound about these creatures, and their bite can cause serious injury, no human fatalities have ever been recorded.

Research at the University of Melbourne, Australia proposes that some lizards in the iguanians and monitor (lizard) families may have venom-producing glands.[1] If proven to be true, however, these would pose little or no danger to humans, as the poison is introduced slowly by chewing, rather than subcutaneous injection as with venomous snakes.[1] According to this study, nine toxins previously thought to only occur in snakes have been discovered out of several thousand.[1] Prior to this theory, swelling and irritation from lizard bites was believed due to bacterial infection and in most cases this is likely, but the study suggests it may be due to partial envenomation.[1] The scientists behind these findings are calling for a re-evaluation of the classification system for lizard species to form a venom clade and if successful may result in changes to the beliefs regarding the evolution of lizards, snakes, and venom.[1]

Relationship to humans

Enlarge picture
Moche Ceramic Depicting Lizard. 200 A.D. Larco Museum Collection Lima, Peru.


Most lizard species are harmless to humans (most species native to North America, for example, are incapable even of drawing blood with their bites). Only the very largest lizard species pose threat of death; the Komodo dragon, for example, has been known to attack and kill humans and their livestock. The venom of the gila monster and beaded lizard is not deadly but they can inflict extremely painful bites due to powerful jaws. The chief impact of lizards on humans is positive as they are significant predators of pest species; numerous species are prominent in the pet trade; some are eaten as food (for example, iguanas in Central America); and lizard symbology plays important, though rarely predominant roles in some cultures (e.g. Tarrotarro in Australian mythology). The Moche people of ancient Peru worshipped animals and often depicted lizards in their art. [3]

Lizards in the Scincomorpha family, which include skinks (such as the blue-tailed skink), often have shiny, iridescent scales that appear moist. They are dry-skinned and generally prefer to avoid water. All lizards are capable of swimming if needed and a few (such as the Nile monitor) are quite comfortable in aquatic environments.

Lizards as pets

Species of lizards sold as pets include iguanas, bearded dragon, leopard geckos, tegus, and monitor lizards. In general, lizards require more maintenance than other exotic pets. Finding a veterinarian whose practice includes lizards is also important.

Classification

Enlarge picture
Coachella Valley Fringe-toed Lizard, Uma inornata
Enlarge picture
Plumed Basilisk, Basiliscus plumifrons
Enlarge picture
Zebra-tailed Lizard, Callisaurus draconoides
Enlarge picture
Gila monster, Heloderma s. suspectum
Enlarge picture
Green tree monitor lizard, Varanus prasinus
'''Suborder Lacertilia (Sauria) - (Lizards)

References

1. ^ Smith, Malcolm A. (1943), The Fauna of British India, Ceylon and Burma Vol II - Sauria, pg 2 & 3.
2. ^ Young, Emma (2005). "Lizards' poisonous secret is revealed". New Scientist. Retrieved on 2007-06-02. 
3. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.

External links

The Jurassic Period is a major unit of the geologic timescale that extends from about 199.6 ± 0.6 Ma (million years ago) to 145.4 ± 4.0 Ma, the end of the Triassic to the beginning of the Cretaceous.
..... Click the link for more information.
Ernst Haeckel

Born January 16 1834(1834--)

Died July 9 1919 (aged 85)

Nationality

..... Click the link for more information.
Kunstformen der Natur (Art Forms of Nature) is a book of lithographic and autotype prints by German biologist Ernst Haeckel. Originally published in sets of ten between 1899 and 1904 and as a complete volume in 1904, it consists of 100 prints of various organisms,
..... Click the link for more information.
Scientific classification or biological classification is a method by which biologists group and categorize species of organisms. Scientific classification also can be called scientific taxonomy, but should be distinguished from folk taxonomy, which lacks scientific basis.
..... Click the link for more information.
Editing of this page by unregistered or newly registered users is currently disabled until (UTC) due to vandalism.
If you are prevented from editing this page, and you wish to make a change, please discuss changes on the talk page, request unprotection, log in, or
..... Click the link for more information.
Chordata
Bateson, 1885

Typical Classes

See below

Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates.
..... Click the link for more information.
Tetrapoda
Broili, 1913

Classes
  • Amphibia
  • Aves
  • Mammalia
  • Sauropsida (Reptilia)
  • Synapsida
Tetrapods (Greek tetrapoda, Latin quadruped
..... Click the link for more information.
Sauropsida*
Goodrich, 1916

Subclasses
  • Anapsida
  • Diapsida
Synonyms
  • Reptilia Laurenti, 1768
Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane, and members of the class
..... Click the link for more information.
Squamata
Oppel, 1811

black: range of Squamata


Suborders
see text

This article is about the Squamata order of reptiles. For the Roman scale armour see: Lorica squamata.

..... Click the link for more information.
In phylogenetics, a group of organisms is said to be paraphyletic (Greek para = near and phyle = race) if the group contains its most recent common ancestor, but does not contain all the descendants of that ancestor.
..... Click the link for more information.
Albrecht Carl Ludwig Gotthilf Günther (also Albert Charles Lewis Gotthilf Gunther; October 3, 1830 – February 1, 1914) was a German-born British zoologist.

Günther was born in Esslingen in Swabia.
..... Click the link for more information.
family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. Exact details of formal nomenclature depend on the Nomenclature Code which applies.
..... Click the link for more information.
Sauropsida*
Goodrich, 1916

Subclasses
  • Anapsida
  • Diapsida
Synonyms
  • Reptilia Laurenti, 1768
Reptiles are tetrapods and amniotes, animals whose embryos are surrounded by an amniotic membrane, and members of the class
..... Click the link for more information.
Squamata
Oppel, 1811

black: range of Squamata


Suborders
see text

This article is about the Squamata order of reptiles. For the Roman scale armour see: Lorica squamata.

..... Click the link for more information.
neutrality is disputed.
* It may contain original research or unverifiable claims.

Please help [ improve the article] or discuss these issues on the talk page. The term adult has three distinct meanings:
  • Grown man or woman; mature person.

..... Click the link for more information.
species is one of the basic units of biological classification. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring.
..... Click the link for more information.
order (Latin: ordo, plural ordines) is a rank between class and family (termed a taxon at that rank). The superorder is a rank between class and order. Exact details of formal nomenclature depend on the Nomenclature Code which applies.
..... Click the link for more information.
1 centimetre =
SI units
010−3 m 0 mm
US customary / Imperial units
010−3 ft 0 in
A centimetre (American spelling: centimeter, symbol cm
..... Click the link for more information.
Caribbean Sea (pronounced IPA: /kəˈrɪbiən/ or /ˌkærɨˈbiːən/
..... Click the link for more information.
Gekkonidae
Gray, 1825

Subfamilies

Aeluroscalabotinae
Eublepharinae
Gekkoninae
Teratoscincinae
Diplodactylinae

Geckos are small to average sized lizards belonging to the family Gekkonidae
..... Click the link for more information.
V. komodoensis

Binomial name
Varanus komodoensis
Ouwens, 1912

Komodo dragon distribution


The Komodo Dragon (Varanus komodoensis
..... Click the link for more information.
For the 1995 movie about hitmen, see .
Cold-blooded organisms maintain their body temperatures in ways different from mammals and birds. The term is now outdated in scientific contexts.
..... Click the link for more information.
In zootomy, the integumentary system is the external covering of the body, comprising the skin, hair, feathers, scales, nails, sweat glands and their products (sweat and mucus).
..... Click the link for more information.
Scale can refer to:
  • Scale (computing). See also Scalability.
  • Scale (map)
  • Scale (ratio)
  • Scale factor
  • Scale (spatial)
  • Scale (zoology)

..... Click the link for more information.
The quadrate bone is part of the skull in most tetrapods, including amphibians, sauropsids ("reptiles"), birds and early synapsids. In these animals it connects to the quadratojugal and squamosal in the skull, and forms part of the jaw joint (the other part is the articular bone at
..... Click the link for more information.
family (Latin: familia, plural familiae) is a rank, or a taxon in that rank. Exact details of formal nomenclature depend on the Nomenclature Code which applies.
..... Click the link for more information.
Perspiration (also called sweating or sometimes transpiration) is the production and evaporation of a fluid, consisting primarily of water as well as a smaller amount of sodium chloride (the main constituent of "table salt"), that is excreted by the sweat glands in the skin of
..... Click the link for more information.
tubercle is generally a wart-like projection, but it has slightly different meaning depending on which family of plants it is used to refer to.

With certain orchids and cacti, it denotes a round nodule, small eminence, or warty outgrowth found on the lip.
..... Click the link for more information.
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs (most notably ankylosaurs and stegosaurus), crocodylians,
..... Click the link for more information.
Oviparous animals are animals that lay eggs, with little or no other embryonic development within the mother. This is the reproductive method of many fish, amphibians and reptiles, all birds, the monotremes, and most insects and arachnids.
..... Click the link for more information.


This article is copied from an article on Wikipedia.org - the free encyclopedia created and edited by online user community. The text was not checked or edited by anyone on our staff. Although the vast majority of the wikipedia encyclopedia articles provide accurate and timely information please do not assume the accuracy of any particular article. This article is distributed under the terms of GNU Free Documentation License.
Herod_Archelaus


page counter