Related topics: species · fossil

Lizard skull fossil is new and 'perplexing' extinct species

In 2017, while browsing the fossil collections of Yale's Peabody Museum of Natural History, University of Texas at Austin graduate student Simon Scarpetta came across a small lizard skull, just under an inch long.

Researchers identify unique populations of dunes sagebrush lizard

New genetic studies reveal important information about populations of the dunes sagebrush lizard, which researchers say may warrant land conservation in areas where unique populations of the species are threatened by habitat ...

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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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