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.
Hyalinobatrachium fleischmanni
Also known as the Northern Glass Frog, this frog’s physical features include primarily green skin, pale yellowish spots, yellow fingertips and translucent skin covering its stomach. A sheet of guanine stretches over several internal organs, such as the heart, but leaves others parts such as the liver exposed for viewing as it only covers half of the frog’s underbelly. They also possess a white vocal sac that can be used to produce sounds for mating. Male frogs have a noticeable hook protruding from its spine, presumably used to fight other frogs, defend its territory or the eggs. They are fierce fighters who will occasionally engage in a wrestling match with other intruding frogs. The female species are slightly larger and lacks this particular feature. There have been more than 100 reported glass frogs throughout Central and South America. 13 species can be found in Costa Rica. Adults tend to be more active during the night when there is rain to keep their skin moist and from drying out. However, strong rains can kill them because their bodies are so fragile. A simple direct shot from a raindrop has been known to kill a glass frog.