Italian crested newt
When newts are inactive or in oxygen-rich environments, respiration can be done through their skin which accounts for 74% of the cutaneous respiration. However, oxygen-poor environments, such as stagnant ponds, pose a threat to the survival of larval newts. This is because oxygen molecules do not readily dissolve in water, and as "T. carnifex" is an immobile animal, extracting oxygen from water is difficult. Newts consequently have external gills at birth that persist until metamorphosis, which assists survival in low-oxygen conditions.
Nepidae
Respiration in the adult is achieved by means of the caudal process, which consists of a pair of half-tubes capable of being locked together to form a siphon. Air is conducted through it to the tracheae at the apex of the abdomen when the tip of the tube is thrust above the surface of the water (similar to a snorkel). In some species the siphon is longer than the body, but in others it is shorter, in a few even less than one-tenth of the body length. In immature forms the siphon is often underdeveloped and respiration takes place through six pairs of abdominal spiracles.