Newt
Newts, as with salamanders in general and other amphibians, serve as bioindicators because of their thin, sensitive skin and evidence of their presence (or absence) can serve as an indicator of the health of the environment. Most species are highly sensitive to subtle changes in the pH level of the streams and lakes where they live. Because their skin is permeable to water, they absorb oxygen and other substances they need through their skin. Scientists study the stability of the amphibian population when studying the water quality of a particular body of water.
Calotriton
Calotriton, or the European brook newts, is a genus of newts native to the Pyrenees and central Catalonia (Catalan Pre-coastal Range). These amphibians were formerly placed within genus "Euproctus", but the genus was resurrected in 2005. Instead of "Euproctus", they seem more closely related to "Triturus", their sister taxon.