How Many Kinds of Reptiles Exist?
There are four groups of living reptiles on the planet today: Crocodilia – 23 species of crocodiles, alligators, gavials, and caimans Sphenodontia – 2 species of tuatara document.getElementById(‘adsense_placeholder_2’).innerHTML = document.getElementById(‘adsense_ad_2_hidden’).innerHTML; Squamata – approximately 7,900 species of lizards, snakes, and amphisbaenids (worm lizards) Testudinata – approximately 300 species of turtles, tortoises, and terrapins What are the General Characteristics of Reptiles? • A tough, dry, scaly skin that is heavily keratinized. Few cutaneous (skin) glands are present. Keratin is a resistant protein found in the epidermis of amniotes. It is protective and prevents water loss across body surfaces. Human hair and nails are made of keratin. • The body is covered and protected by scales and scutes. Scales are made of keratin and are formed from the epidermis. Scutes are structurally similar to scales and serve the same function. • Two sets of paired limbs (tetr
