Reptiles include any cold-blooded vertebrate of the class Reptilia, comprising the turtles, snakes, lizards, crocodilians, amphisbaenians, tuatara, and various extinct members including the dinosaurs. Amphibians include any cold-blooded vertebrate of the class Amphibia, comprising frogs and toads, newts and salamanders, and caecilians, the larvae being typically aquatic, breathing by gills, and the adults being typically semiterrestrial, breathing by lungs and through the moist, glandular skin. Reptiles are defined as any of various cold-blooded vertebrates of the class Reptilia, having skin covered with scales or horny plates, breathing air with lungs, and usually having a three-chambered heart. Unlike amphibians, whose eggs are fertilized outside the female body, reptiles reproduce by eggs that are fertilized inside the female. Though once varied, widespread, and numerous, reptilian lineages, including the pterosaurs, ichthyosaurs, plesiosaurs, and dinosaurs, have mostly become extinct (though birds are living descendants of dinosaurs). The earliest reptiles were the cotylosaurs (or stem reptiles) of the late Mississippian or early Pennsylvanian Period, from which mammals evolved. Modern reptiles include crocodiles, snakes, turtles, and lizards. An amphibian can be defined as a cold-blooded, smooth-skinned vertebrate of the class Amphibia. Amphibians hatch as aquatic larvae with gills and, in most species, then undergo metamorphosis into four-legged terrestrial adults with lungs for breathing air. The eggs of amphibians are fertilized externally and lack an amnion.

Should the location of newly discovered species be hidden?

Discovering a new species can be the defining moment of a biologist's career, but for some it can also mean exposing rare and vulnerable animals to the dark world of the wildlife pet trade, with catastrophic results. It's a scientific dilemma that has led some conservationists to question whether it would be better to hide their findings from the world. In 1999, herpetologist Bryan Stuart was working in Northern Laos when he stumbled across an eye-catching newt he had never seen before. The creature was prehistoric in its appearance with thick, warty skin and bright, yellow dots all the way down its back. He spotted it in a bottle of alcohol that a Lao colleague had brought back from a wedding in a remote part of the country - the poison from the newt's skin had been used to make a drink with special medicinal properties for a toast to the newlyweds. Stuart went in search of the newt in the wild and three years later he published an article in the Journal of Herpetology, announcing the discovery of the new species, Laotriton laoensis.