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.
Ancyronyx
The larvae are exclusively aquatic. They breathe by means of tracheal gills. Spider water beetle adults, like all members of the subfamily Elminae, can also remain indefinitely underwater by means of a plastron, a thin film of gas trapped by hydrophobic bristles (setae) on their body. As the insect breathes, the oxygen concentration in the gas film drops in comparison to the surrounding water, causing new oxygen to diffuse again into the plastron.