Lizard
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Lizards are a very large and widespread group of squamate reptiles, with nearly 5,000 species, 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. While the snakes are recognized as falling phylogenetically within the anguimorph lizards 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 limbs and external ears, while snakes lack both 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 in order to escape from predators, an act called autotomy, but this trait is not universal. 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 centimeters for some chameleons and geckos to nearly three meters (9 feet, 6 inches) in the case of the largest living varanid lizard, the Komodo Dragon. Some extinct varanids reached great size. The extinct aquatic mosasaurs reached 17.5 meters, and the giant monitor Megalania prisca is estimated to have reached perhaps seven meters.
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News tagged with lizards
Warm-blooded dinosaurs worked up a sweat
Nov 11, 2009 |
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(PhysOrg.com) -- Were dinosaurs endothermic (warm-blooded) like present-day mammals and birds or ectothermic (cold-blooded) like present-day lizards? The implications of this simple-sounding question go beyond ...
Going out on a limb: 'Scaffold' to regenerate lost or damaged bones and tissues
Oct 19, 2009 |
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Mother Nature has provided the lizard with a unique ability to regrow body tissue that is damaged or torn ― if its tail is pulled off, it grows right back. She has not been quite so generous with human ...
Reptiles stood upright after mass extinction
Other Sciences / Archaeology & Fossils
Sep 15, 2009 |
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(PhysOrg.com) -- Reptiles changed their walking posture from sprawling to upright immediately after the end-Permian mass extinction, the biggest crisis in the history of life that occurred some 250 million ...
First genetic link between reptile and human heart evolution
Sep 02, 2009 |
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Scientists at the Gladstone Institute of Cardiovascular Disease have traced the evolution of the four-chambered human heart to a common genetic factor linked to the development of hearts in turtles and other ...
Tropical lizards can't take the heat of climate warming
Mar 03, 2009 |
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From geckos and iguanas to Gila monsters and Komodo dragons, lizards are among the most common reptiles on Earth. They are found on every continent except Antarctica. One even pitches car insurance in TV ads. ...
Four, three, two, one... pterosaurs have lift off
Other Sciences / Archaeology & Fossils
Jan 06, 2009 |
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Pterosaurs have long suffered an identity crisis. Pop culture heedlessly — and wrongly — lumps these extinct flying lizards in with dinosaurs. Even paleontologists assumed that because the creatures flew, they were birdlike ...
Rediscovering the dragon's paradise lost
Other Sciences / Archaeology & Fossils
Sep 30, 2009 |
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The world's largest living lizard species, the Komodo dragon (Varanus komodoensis), is vulnerable to extinction and yet little is known about its natural history. New research by a team of palaeontologists and ar ...
For horned lizard, horns alone do not make the species
Jul 21, 2009 |
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How do you recognize a new species? A thorough study of the million-year evolution of California's horned lizards, sometimes referred to as "horny toads," shows that when it comes to distinguishing such recently ...
Ancient fossils shed light on anatomical changes accompanying evolution of first land vertebrates
Other Sciences / Archaeology & Fossils
Jul 06, 2009 |
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Cartoon depictions of the first animals to emerge from the ocean and walk on land often show a simple fish with feet, venturing from water to land. But according to Jennifer Clack, a paleontologist at the ...
Birds with a nose for a difference
Jun 30, 2009 |
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Avoidance of inbreeding is evident amongst humans, and has been demonstrated in some shorebirds, mice and sand lizards. Researchers writing in the open access journal BMC Evolutionary Biology now report that it also occurs ...
Boy or girl? In lizards, egg size matters
Jun 04, 2009 |
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Whether baby lizards will turn out to be male or female is a more complicated question than scientists would have ever guessed, according to a new report published online on June 4th in Current Biology. The study shows that f ...
A venomous tale: Vipers shape lizards' tail-shedding abilities
Mar 25, 2009 |
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(PhysOrg.com) -- University of Michigan ecologists and their colleagues have answered a question that has puzzled biologists for more than a century: What is the main factor that determines a lizard's ability ...
Genetic study finds treasure trove of new lizards
Mar 04, 2009 |
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(PhysOrg.com) -- University of Adelaide research has discovered that there are many more species of Australian lizards than previously thought, raising new questions about conservation and management of Australia's ...
Native Lizards Evolve to Escape Attacks by Fire Ants
Biology /
Jan 20, 2009 |
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(PhysOrg.com) -- Penn State Assistant Professor of Biology Tracy Langkilde has shown that native fence lizards in the southeastern United States are adapting to potentially fatal invasive fire-ant attacks ...
Limb loss in lizards -- evidence for rapid evolution
Biology /
Nov 11, 2008 |
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Small skink lizards, Lerista, demonstrate extensive changes in body shape over geologically brief periods. Research published in the open access journal BMC Evolutionary Biology shows that several species of th ...
