What are the Different Classes of Reptiles?

Reptiles have been around for more than 300 million years. Some classes are evolved versions of prehistoric ancestors, such as the crocodile, lizard and snake. According to the University of Minnesota, present-day scientists classify reptiles into four groups known as "orders."  Each order is made up of numerous species, with snakes and lizards having the most.

Squamata

The squamata order features species of lizard, snake and amphisbaenids, or in laymen’s terms, worm-lizards. This class features approximately 8,000 different species and two subspecies of reptile. The two classes of subspecies consist of serpentes, or snakes, which include pythons, cobras and constrictors and lacertilia, or lizards with the ability to regrow body parts, like iguanas, geckoes and chameleons. This reptile order is known for its sensitivity to vibrations and sense of smell, as opposed to having good eyesight or hearing. Most of the squamata class live in warmer climates throughout the world.

Testudines

The next largest reptile order is the testudines. This class consists of more than 300 different species of turtle and tortoise. Testudines are the only class of reptile with a shell, making them vastly different from any other species. What many people do not know is that this shell is not removable. A testudine's shell is part of its structural makeup, acting as a rib cage on the outside of its body.

Crocodilia

The crocodilian class is made up of 23 species of crocodiles, alligators, caimans and gharials. Crocodilians are found on four of the world's continents, living in tropical climates. All crocodilian species have a similar body shape and armored scales. The differences between crocodilian species lie mostly in the snout shape, and body size and color.

Sphendontia

The fourth class of reptile is the sphendontia. For this class, there are only two species of tuatara lizard. The tuatara is found in New Zealand and resembles the iguana lizard. The tuatara species is extremely rare and has been endangered for close to 100 years. Tuatara's live within seabird colonies and its life span ranges between 50 and 80 years.