any of about 56 species of lizards in the family Teiidae. The genus is common in North America, particularly in the southwestern deserts, and its range extends through Central America and across South America to Argentina. Species also occur on some islands, including the Netherlands Antilles off the coast of Venezuela. Their size varies from 20 to more than 50 cm (8 to 20 inches). The common name of this genus is derived from the lizards' ability to run at impressive speeds; some species can run almost 28 km (17 miles) per hour over short distances.
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