Reptiles, as most commonly defined, are the animals in the class Reptilia, a paraphyletic grouping comprising all sauropsid amniotes except Aves (birds). Living reptiles comprise turtles, crocodilians, squamates and rhynchocephalians (tuatara). As of March 2022, the Reptile Database lists about the class includes about 11,700 species. In the traditional Linnaean classification system, birds are considered a separate class to reptiles. However, crocodilians are more closely related to birds than they are to other living reptiles, and so modern cladistic classification systems include birds within Reptilia, redefining the term as a clade. Other cladistic definitions abandon the term reptile altogether in favor of the clade Sauropsida, which refers to all amniotes more closely related to modern reptiles than to mammals. The study of the traditional reptile orders, historically combined with that of modern amphibians, is called herpetology.
The Lepidosauria is a subclass or superorder of reptiles, containing the orders Squamata and Rhynchocephalia. Squamata includes snakes, lizards, and amphisbaenians. Squamata contains over 9,000 species, making it by far the most species-rich and diverse order of reptiles in the present day. Rhynchocephalia was a formerly widespread and diverse group of reptiles in the Mesozoic Era. However, it is represented by only one living species: the tuatara, a superficially lizard-like reptile native to New Zealand.
Marine reptiles are reptiles which have become secondarily adapted for an aquatic or semiaquatic life in a marine environment.
Gabriel Bibron was a French zoologist and herpetologist. He was born in Paris. The son of an employee of the Museum national d'histoire naturelle, he had a good foundation in natural history and was hired to collect vertebrates in Italy and Sicily. Under the direction of Jean Baptiste Bory de Saint-Vincent (1778–1846), he took part in the Morea expedition to Peloponnese.