a genus of fishes of the subclass Dipnoi. There are four species (according to other data, three), the largest of which are Protopterus aethiopicus (reaches a length of 2 m) and the better-known P. annectens. Protopteruses inhabit fresh-waters of tropical Africa. The cylindrical body is covered with small scales; the paired fins are flagellate. The larvae have external gill appendages.
Protopteruses feed on fish and large invertebrates, mostly at night. They spawn in August and September (during the rainy season). The male builds a brood nest in the form of an underground burrow and guards the eggs and larvae. If the water should dry up completely, the fishes enter a torpid state. They burrow into the bottom and form a cocoon that fits tightly around the body. During this period, they breathe atmospheric air and may go without water for five to nine months or longer.