lizard

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(lĭz'ərd) pronunciation
n.
  1. Any of numerous reptiles of the suborder Sauria or Lacertilia, characteristically having a scaly elongated body, movable eyelids, four legs, and a tapering tail.
  2. Leather made from the skin of one of these reptiles.

[Middle English, from Old French lesarde, from Latin lacertus, lacerta.]



Day gecko (genus Phelsuma).
(click to enlarge)
Day gecko (genus Phelsuma). (credit: © Digital Vision/Getty Images)
Any of about 4,450 species of reptiles constituting the suborder Sauria. They are most diverse and abundant in the tropics but are found from the Arctic Circle (one species) to southern Africa, South America, and Australia. Like snakes, lizards have scales, paired male copulatory organs, and a flexible skull. Typical lizards have a moderately cylindrical body, four well-developed legs (although some lizards are legless), a tail slightly longer than the head and body combined, and movable lower eyelids. They range in size from 1-in. (3-cm) geckos to the 10-ft (3-m) Komodo dragon, but most are about 12 in. (30 cm) long. Ornamentation includes crests on the head, back, or tail; spines; brightly coloured throat fans; and throat frills. Most species feed on insects and rodents, but some, such as the iguana, eat plants. Gila monster; horned toad.

For more information on lizard, visit Britannica.com.

lizard, a reptile of the order Squamata, which also includes the snake. Lizards form the suborder Sauria, and there are over 3,000 lizard species distributed throughout the world (except for the polar regions), with the greatest number found in warm climates. They range in size from species under 21/2 in. (6.4 cm) long to the 10-ft (3-m) Komodo dragon (see monitor) of SE Asia.

Lizards typically have four legs with five toes on each foot, although a few, such as the worm lizard and the so-called glass snake, are limbless, retaining only internal vestiges of legs. Lizards are also distinguished from snakes by having ear openings, movable eyelids, and less flexible jaws. As in snakes, there is a chemosensory organ opening in the roof of the mouth. The tongue, which may be short and wide, slender and forked, or highly extendible, conveys particles from the environment to this organ. The skin of the lizard is scaly and in most species is molted in irregular patches. Members of several lizard families, notably the chameleons, undergo color changes under the influence of environmental and emotional stimuli.

Many lizards are arboreal, and many terrestrial species are well adapted for climbing. They are often fast runners, some achieving speeds of over 15 mi (24 km) per hr. Some are adapted for burrowing. Most can swim and a few lead a semiaquatic existence, among them the single marine species, an iguana of the Galapagos Islands. Gliding forms, the flying dragons, are found in the forests of SE Asia. The gila monster and the related beaded lizard of the North American deserts are the only known poisonous lizards; some other lizards, such as the lace monitor of Australia, produce a nonfatal venom. Despite folklore, the bite of the gecko is not poisonous. Members of most species are carnivorous, feeding especially on insects, but some are herbivorous or omnivorous.

Fertilization is internal in lizards; males have paired copulatory organs, characteristic of the order. In most species females lay eggs, which they bury in the ground, but in some the eggs are incubated in the oviducts and hatched as they are laid. In both types the young have a special temporary tooth for rupturing the shell. In a few species there is true viviparity, or live birth, with the young nourished by a simple placenta.

The greatest number of species in the United States is found in the South and West. The majority are members of the iguana family, including the collared lizards, swifts, utas, horned lizards (popularly known as horned toads), and the so-called American chameleon, or anole. These are day-active lizards commonly seen basking on rocks. Most are valuable destroyers of insects.

Lizards are classified in the phylum Chordata, subphylum Vertebrata, class Reptilia, order Squamata, suborder Sauria.

Bibliography

See W. M. Milstead, ed., Lizard Ecology (1967); H. S. Fitch, Reproductive Cycles of Lizards and Snakes (1970); B. R. Headstrom, Lizards as Pets (1971).


Cornwall. Lisart (1086) (DB). ‘Court on a height’. Cornish *lys + *ardh.

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sign description: The closed fist begins at the mouth, then the index finger moves outward in a quick motion.




Though a dream about any kind of an animal can represent our "animal" nature, lizards are not natural candidates for this role. Perhaps the lizard is a chameleon, which changes its color to conform to the environment. A dream lizard might also be a "lounge lizard."


Member of the suborder Lacertilia. There are about 2500 species of true lizards and allied groups. None of them is poisonous.

  • l. poisoning — infection with the fluke platynosomum fastosum.
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Lizard
Temporal range: Early Jurassic – Recent, 199–0 Ma
Possible Late Triassic record.
Central bearded dragon, Pogona vitticeps
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Superclass: Tetrapoda
Class: Reptilia
Subclass: Diapsida
Order: Squamata
Suborder: Lacertilia*
Günther, 1867
Families

Many, see text.

Range of the Lizards, all species

Lizards are a widespread group of squamate reptiles, with more than 5600 species [1], ranging across all continents except Antarctica as well as most oceanic island chains. The group, traditionally recognized as the suborder Lacertilia, is defined as all extant members of the Lepidosauria (reptiles with overlapping scales), which are neither sphenodonts (i.e., tuatara) nor snakes – they form an evolutionary grade.[2] While the snakes are recognized as falling phylogenetically within the Toxicofera clade from which they evolved, the Sphenodonts are the sister group to the Squamates, the larger monophyletic group, which includes both the lizards and the snakes.

Lizards typically have feet and external ears, while snakes lack both of these characteristics. However, because they are defined negatively as excluding snakes, lizards have no unique distinguishing characteristic as a group. Lizards and snakes share a movable quadrate bone, distinguishing them from the sphenodonts, which have a more primitive and solid diapsid skull. Many lizards can detach their tails to escape from predators, an act called autotomy, but this ability is not shared by all lizards. Vision, including color vision, is particularly well developed in most lizards, and most communicate with body language or bright colors on their bodies as well as with pheromones.

The adult length of species within the suborder ranges from a few cm for chameleons like Brookesia micra and geckos like Sphaerodactylus ariasae to nearly 3 m (9.8 ft) in the case of the largest living varanid lizard, the Komodo Dragon. Some extinct varanids reached great size. The extinct aquatic mosasaurs reached 17 m (56 ft), and the giant monitor Megalania is estimated to have reached perhaps 7 m (23 ft).

Contents

Physiology

Feral Jackson's Chameleon from a population introduced to Hawaii in the 1970s

Sight is very important for most lizards, both for locating prey and for communication, and, as such, many lizards have highly acute color vision. Most lizards rely heavily on body language, using specific postures, gestures, and movements to define territory, resolve disputes, and entice mates. Some species of lizard also utilize bright colors, such as the iridescent patches on the belly of Sceloporus. These colors would be highly visible to predators, so are often hidden on the underside or between scales and only revealed when necessary.

The particular innovation in this respect is the dewlap, a brightly colored patch of skin on the throat, usually hidden between scales. When a display is needed, the lizards erect the hyoid bone of their throat, resulting in a large vertical flap of brightly colored skin beneath the head which can be then used for communication. Anoles are particularly famous for this display, with each species having specific colors, including patterns only visible under ultraviolet (UV) light, as many lizards can see UV light.[citation needed] Many lizard species are also capable of severing their tails when faced with danger. Although severing and regrowing tails is a strenuous process for a lizard, this mechanism is often used by lizards to save their lives.

Lizard...

Evolution and relationships

Fossil mosasaur Prognathodon, a varanoid

The retention of the basic 'reptilian' amniote body form by lizards makes it tempting to assume any similar animal, alive or extinct, is also a lizard. However, this is not the case, and lizards as squamates are part of a well-defined group.

The earliest amniotes were superficially lizard-like, but had solid, box-like skulls, with openings only for eyes, nostrils, termed the anapsid condition. Turtles retain this skull form. Early anapsids later gave rise to two new groups with additional holes in the skull to make room for and anchor larger jaw muscles. The Synapsids, with a single fenestra, gave rise to the superficially lizard-like Pelycosaurs, which include Dimetrodon and the Therapsids, including the Cynodonts, from which the modern mammals would evolve.

The modern Tuatara retains the basic lepidosaur skull, distinguishing it from true lizards in spite of superficial similarities. Squamates, including snakes and all true lizards, further lightened the skull by eliminating the lower margin of the lower skull opening.

The earliest known fossil remains of a lizard belong to the iguanian species Tikiguania estesi, found in the Tiki Formation of India, which dates to the Carnian stage of the Triassic period, about 220 million years ago.[3] However, doubt has been raised over the age of Tikiguania because it is almost indistinguishable from modern agamid lizards. The Tikiguania remains may instead be late Tertiary or Quaternary in age, having been washed into much older Triassic sediments.[4] Lizards are most closely related to a group called Rhynchocephalia, which includes the tuatara. Rhynchocephalians first appeared in the Late Triassic, so it can be inferred that the lizard-rhynchocephalian divergence occurred at this time and that the earliest lizards appeared in the Triassic.[4]

Mitochondrial phylogenetics suggests that the first lizards evolved in the late Permian. Most evolutionary relationships within the squamates are not yet completely worked out, with the relationship of snakes to other groups being most problematic. From morphological data, Iguanid lizards have been thought to have diverged from other squamates very early, but recent molecular phylogenies, both from mitochondrial and nuclear DNA, do not support this early divergence.[5] Because snakes have a faster molecular clock than other squamates,[5] and there are few early snake and snake ancestor fossils,[6] it is difficult to resolve the relationship between snakes and other squamate groups.

Lizard diversification

Within the Lacertilia are found four generally recognized suborders, Iguania, Gekkota, Amphisbaenia and Autarchoglossa, with the "blind skinks" in the family Dibamidae having an uncertain position. While traditionally excluded from the lizards, the snakes are usually classified as a clade with a similar subordinal rank.[7]

Iguania

Anoles mating, Gainesville, Florida

The suborder Iguania, found in Africa, south Asia, Australia, the New World, and with iguanas colonizing the islands of the west Pacific, form the sister group to the remainder of the squamata. They are largely arboreal, and have primitively fleshy, non-prehensile tongues, some even have scales, but this condition is obviously highly modified in the chameleons. This clade includes the following families:

Gekkota

Active hunters, the Gekkota includes three families comprising the distinctive cosmopolitan geckos and the legless flap-footed lizards of Australia and New Zealand. Like snakes, the flap-footed lizards and most geckos lack eyelids. Unlike snakes, they use their tongues to clean their often highly developed eyes. While gecko feet have unique surfaces that allow them to cling to glass and run on ceilings,[8] the flapfoot has lost its limbs. The three families of this suborder are:

Relationship with humans

Komodo dragons on Rinca
A lizard as the symbol of the Military Organization Lizard Union, a WWII Polish anti-Nazi resistance group
Green iguanas (Iguana iguana), are popular exotic pets

Most lizard species are harmless to humans. Only the largest lizard species, the Komodo dragon, which reaches 3.3 m (11 feet) in length and weighs up to 166 kg (365 pounds), has been known to stalk, attack, and, on occasion, kill humans. An eight-year-old Indonesian boy died from blood loss after an attack in 2007.[9] The venom of the Gila monster and beaded lizard is not usually deadly but they can inflict extremely painful bites due to powerful jaws.

Numerous species of lizard are kept as pets, including iguanas, anoles, geckos (such as the popular leopard gecko) Some lizards have an affinity for humans, but many are suspicious or skittish around humans. Lizards that bite humans are very rare. Lizards are predominantly insectivorous, but some eat fruit, or vegetables. Live crickets and worms are the most typical foods for pet lizards, though the crested gecko (not a friendly lizard to humans) can feed entirely on fruit.

Lizard symbolism plays important though rarely predominant roles in some cultures (e.g., Tarrotarro in Australian Aboriginal mythology). The Moche people of ancient Peru worshipped animals and often depicted lizards in their art.[10] According to a popular legend in Maharashtra, a Common Indian Monitor, with ropes attached, was used to scale the walls of the Sinhagad fort in the Battle of Sinhagad.[11]

Green Iguanas are eaten in Central America and Uromastyx in Africa. In North Africa, Uromastyx are considered dhaab or 'fish of the desert' and eaten by nomadic tribes.[12]

Classification

Gekko gecko in Thailand
Close-up of the head of the legless fossorial amphisbaenid Rhineura
Underside of a Thorny devil, an agamid, Western Australia
The Eastern blue-tongued lizard, a scincomorph

Suborder Lacertilia (Sauria) – (Lizards)


References

  1. ^ Reptile Database. Retrieved on 2012-04-22
  2. ^ Gibbons, J. Whitfield; Gibbons, Whit (1983). Their Blood Runs Cold: Adventures With Reptiles and Amphibians. Alabama: University of Alabama Press. p. 164. ISBN 978-0-8173-0135-4. 
  3. ^ Datta, P.M. and Ray, S. (2006). "Earliest lizard from the Late Triassic (Carnian) of India". Journal of Vertebrate Paleontology 26 (4): 795–800. doi:10.1671/0272-4634(2006)26[795:ELFTLT]2.0.CO;2. 
  4. ^ a b Hutchinson, M.N.; Skinner, A.; and Lee, M.S.Y.. "Tikiguania and the antiquity of squamate reptiles (lizards and snakes)". Biology Letters in press. doi:10.1098/rsbl.2011.1216. http://rsbl.royalsocietypublishing.org/content/early/2012/01/24/rsbl.2011.1216.full. 
  5. ^ a b Kumazawa, Yoshinori (2007). "Mitochondrial genomes from major lizard families suggest their phylogenetic relationships and ancient radiations". Gene 388 (1–2): 19–26. doi:10.1016/j.gene.2006.09.026. PMID 17118581. 
  6. ^ "Lizards & Snakes Alive!". American Museum of Natural History. http://www.amnh.org/exhibitions/lizards/snakes/world.php. Retrieved 2007-12-25. 
  7. ^ Squamata Oppel, 1811. the Integrated Taxonomic Information System. ITIS.org
  8. ^ Santos, Daniel; Matthew Spenko, Aaron Parness, Kim Sangbae, Mark Cutkosky (2007). Journal of Adhesion Science and Technology 21 (12-13): 1317–1341. http://www.brill.nl/journal-adhesion-science-and-technology. "Gecko "feet and toes are a hierarchical system of complex structures consisting of lamellae, setae,and spatulae. The distinguishing characteristics of the gecko adhesion system have been described [as] (1) anisotropic attachment, (2) high pulloff force to preload ratio, (3) low detachment force, (4) material independence, (5) self-cleaning, (6) anti-self sticking and (7) non-sticky default state. ... The gecko’s adhesive structures are made from ß-keratin (modulus of elasticity [approx.] 2 GPa). Such a stiff material is not inherently sticky; however, because of the gecko adhesive’s hierarchical nature and extremely small distal features (spatulae are [approx.] 200 nm in size), the gecko’s foot is able to intimately conform to the surface and generate significant attraction using van der Waals forces." 
  9. ^ Komodo dragon kills boy in Indonesia – World news – Asia-Pacific – msnbc.com. MSNBC. Retrieved on 2011-11-07.
  10. ^ Berrin, Katherine & Larco Museum. The Spirit of Ancient Peru:Treasures from the Museo Arqueológico Rafael Larco Herrera. New York: Thames and Hudson, 1997.
  11. ^ Auffenberg, Walter (1994). The Bengal Monitor. University Press of Florida. p. 494. ISBN 0-8130-1295-3. 
  12. ^ Grzimek, Bernhard. Grzimek’s Animal Life Encyclopedia (Second Edition) Vol 7 – Reptiles. (2003) Thomson – Gale. Farmington Hills, Minnesota. Vol Editor – Neil Schlager. ISBN 0-7876-5783-2 (for vol.7). p. 48
General references

External links

  • Data related to Sauria at Wikispecies


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Dansk (Danish)
n. - firben, øgle, tovende med indsplejset kous, vejviserklåde

Nederlands (Dutch)
hagedis

Français (French)
n. - lézard

Deutsch (German)
n. - Eidechse

Ελληνική (Greek)
n. - (ζωολ.) σαύρα

Italiano (Italian)
lucertola

Português (Portuguese)
n. - lagarto (m) (Zool.)

Русский (Russian)
ящерица, шкурка ящерицы, Гщерица (созвездие)

Español (Spanish)
n. - lagarto, lagartija

Svenska (Swedish)
n. - (zool.) ödla, (sjö.) ridare

中文(简体)(Chinese (Simplified))
蜥蜴

中文(繁體)(Chinese (Traditional))
n. - 蜥蜴

한국어 (Korean)
n. - 도마뱀, 섭렵하는 놈

日本語 (Japanese)
n. - トカゲ

العربيه (Arabic)
‏(الاسم) العضاءة, السحليه, السقايه حيوان‏

עברית (Hebrew)
n. - ‮לטאה‬


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Reptile (dream symbols)