Cutaneous respiration
The skin of amphibians is a major site of respiration in all species for which measurements are available. Cutaneous respiration is the sole respiratory mode of lungless salamanders (family Plethodontidae) which lack lungs entirely yet constitute the largest family of salamanders. Cutaneous respiration in frogs and other amphibians may be the primary respiratory mode during colder temperatures.
Hyperolius nitidulus
"Hyperolius nitidulus" live in an environment with a wet season that can be cold and humid, and an extremely hot and dry season. During the hot and dry season the frog is dependent on water therefore it has special adaptations to survive the extreme climate. "Hyperolius nitidulus" is known for its unique aestivation behavior during the hot and dry season. During dry season "Hyperolius nitidulus" do not seek shelter or hide, instead, they fully expose themselves to the sun by sitting on dry plants to reduce rapid water loss and can remain in this sitting position for months without food or water. The juveniles only move when they are in serious danger. They sit with their legs held tightly to the body and feet hidden under their skin folds. During this period, since there is no food or water intake, the juvenile frog does not urinate or defecate. The body stores all nitrogenous waste as urea in body fluids and purines. As the hot weather increases the dorsal skin of the frog becomes white due to the presence iridophores that can reflect light like a mirror since they are filled with purines crystals.