Cash, W. Ben Department of Biology, Maryville College, Maryville, Tennessee.
Last reviewed:April 2021
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- Fundamental characteristics
- Living reptiles
- Position of birds
- Related Primary Literature
- Additional Reading
A class of vertebrates composed of turtles, lizards, snakes, crocodilians, amphisbaenians, and tuataras, as well as a variety of extinct forms. The members of the vertebrate class Reptilia are tetrapods, meaning that they possess four limbs or are descended from four-limbed ancestral forms. In general, the class Reptilia comprises four living groups—Testudines (Chelonia; turtles) [Fig. 1], Rhynchocephalia (tuataras), Squamata [lizards, amphisbaenians (worm lizards), and snakes], and Crocodylia (Crocodilia; crocodilians). However, many taxonomic and phylogenetic experts support a different arrangement of the reptile group that asserts that birds have a far closer evolutionary relationship to reptiles than once thought, and in fact should be considered reptiles. All other reptilian groupings (for example, dinosaurs, winged pterosaurs, and marine placodonts) are extinct. The study of reptiles, as well as amphibians, is known as herpetology. See also: Amphibia; Aves; Chelonia; Crocodylia; Dinosauria; Placodontia; Pterosauria; Rhynchocephalia; Squamata; Tetrapoda; Vertebrata
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