Fauna of Scotland
Only six amphibians and four land reptiles are native to Scotland. The amphibians include three species of newt: the great crested, of which fewer than 1,000 individuals survive; the smooth, and the palmate. The other amphibians are the common toad, the natterjack toad, found in only four locations in the south-west, and the common frog. A single alien amphibian is known in Scotland, the Alpine newt, a recent escapee confined to the Edinburgh area.
Neoteny
Many species of salamander, and amphibians in general, are known to have neotenized characteristics because of the environment they live in. Axolotl and olm are species of salamander that retains their juvenile aquatic form throughout adulthood, examples of full neoteny. Gills are a common juvenile characteristic in amphibians that are kept after maturation; an example of this would be a comparison of the tiger salamander and the rough-skinned newt, both of which retain gills into adulthood.