Dipnoics are fish that can survive outside the water, as they have a swimming bladder adapted to aerial breathing. They existed in abundance during the Triassic period, but currently there are only three species. One who lives in the Amazon, another in Australia and the last in tropical Africa. They are Lepidosiren, Neoceratodus and Protopterus, respectively.
This nomenclature means “double breather”, because in addition to gills, they have functional lungs. As a result, dipnoicos need air to survive and in the absence of this respiratory activity, the gills can degenerate and result in drowning.
This double-breathing characteristic makes researchers believe that dipnoic fish are ancestors of all terrestrial vertebrates and that they have adapted for survival during major droughts.
Scholars have discovered fossils of burrows of dipnoic fish that date back 395 million years ago, when they would have developed the ability to breathe air.
Anatomically, dipnoic fish have skulls and bony jaws, but have no teeth on the underside. The rest of the body, such as the back, tail and anus, form a single fin. Regarding food, they are omnivorous and feed on crustaceans, larvae and mollusks.
The Protopterus species that lives in Africa is the one that suffers most from the lack of water. For this reason, fish of this species dig a kind of hole in the mud when there is a long period of drought. In this hole, it can survive up to 2 years without water, as long as it has an air intake. When the dry season ends, they return to being aquatic