PROTOPTERUS : AFRICAN LUNG FISH

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1) PROTOPTERUS : AFRICAN LUNG FISH

1.1) CLASSIFICATION OF PROTOPTERUS : AFRICAN LUNG FISH

1.2) GEOGRAPHICAL DISTRIBUTION

1.3) HABIT AND HABITAT

1.4) GENERAL CHARACTERSTICS OF PROTOPTERUS : AFRICAN LUNG FISH

1.5) SPECIAL FEATURES

1.6) IDENTIFICATION

1.7) REFERENCES

CLASSIFICATION OF PROTOPTERUS : AFRICAN LUNG FISH

Phylum :- CHORDATA ( Notochord and dorsal tubular nerve cord present and gill-slits present).

Group :- CRANIATA ( Cranium with brain present ).

Subphylum :- VERTEBRATA (Vertebral column present ).

Division :- GNATHOSTOMATA ( Jaws and paired appendages present ).

Super class :- PISCES (Paired fins , gills and skin with scales)

Class :- OSTEICHTHYES ( Bony fishes ).

SUB-CLASS :- CHOANICHTHYES ( Nostrils connected to mouth cavity. Paired fins with larger median lobe ).

SUPER ORDER :- DIPNOI ( Lung tish. Body long and slender. Premaxilla or maxilla absent. Air bladder (Dipneusti) lung like ).

Order :- LEPIDOSIRENIFORMES ( Body ell-like, scales. small, burrowing fish).

GENUS :- Protopterus (African lung fish)

GEOGRAPHICAL DISTRIBUTION

Protopterus has wide distribution. It is found in the swamps of great African continent, the Nile, Congo basin, Lake Tanganyika.

HABIT AND HABITAT

The fishes are adapted for burrowing life. They live in burrows made in muddy water. In dry season, during aestivation, they retire to vertical burrows (nests) in mud lined with mucus. It comes to surface to engulf the air.

GENERAL CHARACTERSTICS OF PROTOPTERUS : AFRICAN LUNG FISH

Body is elongated, cylindrical, eel like and IS completely enclosed by small cycloid scales. Body divided into head, trunk and tail.
Commonly called as African lung fish.
Head contains small eyes, nostrils and mouth.
Dorsal, caudal and anal fins continuous.
Pectorals and pelvic fins are reduced to slender appendages and without fin rays.
There are six branchial arches and five clefts.
Larval gills are retained as vestigial organs throughout life.
There are two lungs (air bladders) extending throughout body cavity.
Lateral line well developed. Kidneys not so elongated.
Larva contains four pairs of apparent external gills. In some species vestiges of these may be found in the adult just above the opening of the operculum.

SPECIAL FEATURES

Protopterus is an air-breather fish. Protopterus annectens and 2 other species of Central Africa retire to burrow themselves in mud, where mucus dries up to form ‘cocoon’ with lid and a tuhe which is connected with the mouth of the fish for breathing. It spawns after return of water. These lung fishes show combination of primitive and specialized characters. Presence of spiral valve in the intestine, cloaca, conus and unconstricted notochord are primitive characters. While lack of ossification in the cartilaginous cranium, absence of premaxillae and maxillae and presence of dental plates on jaws are specialized characters. Presence of internal nostrils, lung respiration and
autostylic suspensorium show similarity with Amphibians.