Question

The three living lungfishes namely Protopterus, Lepidosiren and Neoceratodus are respectively distributed in which following countries of the world?
A) Africa, South America and Australia
B) Africa, Australia and South America
C) India, Africa and South America
D) South America, England and Africa

Answer 1

Hint: At present, there are only a group of six known species of living air-breathing Lungfishes. They are generally large in size, have disjoint distribution over Earth’s tropical regions and live a peculiar mode of life.

Complete answer:
Protopterus is a lungfish which is also referred to as African Lungfish of the family Protopteridae. They have an elongated body with a long thread-like pectoral and paired pelvic fins. This kind of eel-like fishes is believed to be the connecting link between the fishes and amphibians. It also has characteristic features of amphibians like internal nostrils, lungs and heart. They are carnivorous and usually inhabit shallow waters such as in swamps and marshy areas.
Lepidosiren, also known as South American Lungfish, is the single species of lungfish spotted with gold on a black background. This species has an elongated and almost eel-like body. These lungfishes prefer stagnant waters that are usually found in swamps and slow-moving waters of the Amazon, Paraguay and lower Parana river in South America. Other common names of this species include American mud-fish and scaly salamanderfish. Juvenile lungfishes feed on larval insects and snails while adults are omnivorous and feed on marine vertebrates, invertebrates such as snails, shrimp, and algae. The young Lepidosiren appears with four external gills like amphibians. Then at an age of 7 weeks they become air-breathing and the external gills begin to decline.
Neoceratodus, also known as Australian lungfish, has the unique ability to breathe air using a single lung. When streams become stagnant during dry periods, or when water quality changes it can survive for several days out of water with the help of its single lung. Its body is covered with large, bony, overlapping scales with a flattened scale. It is also known as Queensland lungfish, Burnett salmon and Barramundi.

Hence, the correct answer is option A: Africa, South America and Australia

Note: Historically, Lungfish have been called salamanderfish, but this term is often known as Lepidogalaxias salamandroides. It possesses characteristic features of both the classes of Fishes and Amphibians.