Related topics: species · fossil

Q&A: Meet the bug that tastes 'like quinine with habanero'

What is velvety, red, pea-sized and can be seen scurrying across the ground in the desert Southwest after a torrential rainstorm? If you have no clue, you're not alone. According to Justin Schmidt, an adjunct scientist with ...

Eating fire ants could prepare lizards for future fire ant attack

Eating fire ants might prepare a lizard's immune system to be stung by the ants, according to a new study by researchers at Penn State. The study comprehensively assessed how the immune system responds to lizards eating and ...

Tiny limbs and long bodies: Coordinating lizard locomotion

Snakes and lizards have distinct body movement patterns. Lizards bend from side to side as they retract their legs to walk or run. Snakes, on the other hand, slither and undulate, like a wave that travels down the body. However, ...

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Lizard

Many, see text.

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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