LEPIDOSIREN PARADOXA : AMERICAN LUNG FISH

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1) LEPIDOSIREN PARADOXA : AMERICAN LUNG FISH

1.1) CLASSIFICATION OF LEPIDOSIREN PARADOXA : AMERICAN LUNG FISH

1.2) GEOGRAPHICAL DISTRIBUTION

1.3) HABIT AND HABITAT

1.4) GENERAL CHARACTERSTICS OF LEPIDOSIREN PARADOXA : AMERICAN LUNG FISH

1.5) SPECIAL FEATURES

1.6) IDENTIFICATION

1.7) REFERENCES

CLASSIFICATION OF LEPIDOSIREN PARADOXA : AMERICAN 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 Fish. Body long and slender. Premaxilla or maxilla absent. Air bladder (Dipneusti) lung like ).

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

GENUS :- Lepidosiren

SPECIES :- paradox

GEOGRAPHICAL DISTRIBUTION

Lepidosiren or American lung fish is distributed in Amazon and Paraguay basins and plains of South America.

HABIT AND HABITAT

Lepidosiren inhabits swampy places. It makes a burrow lined by mucus in muddy water. It aestivates during dry season in burrow constructed for the purpose. Entrance of burrow is plugged with a mud stopper, ventilated by several round holes.

GENERAL CHARACTERSTICS OF LEPIDOSIREN PARADOXA : AMERICAN LUNG FISH

Commonly called as South American lung fish. Body divided into head, trunk and tail.
Body elongated and eel-like, 3 feet in length and covered with cycloid scales.
Gill slits are 4 in number.
Eyes are comparatively reduced.
Paired fins (pectoral and pelvic) are reduced to slender styliform appendages formed of jointed axis.
During breeding season vascular filaments develop on the pelvic fins of the male. Filaments are considered to be respiratory. The larva possesses four gills.
Fish has two lungs (air bladders).
Glottis is provided with a movable epiglottis.
Dorsal fin, caudal fin and anal fin continuous.
Lateral line present.

SPECIAL FEATURES

Lepidosiren or American lung fish shows parental care forming L-shaped nests. The fish aestivates in mud during dry season, but it has no cocoon formation habit. This lung fish also reveals combination of primitive and specialized characters. The former characters comprise of unconstricted notochord, presence of conus valve in the heart and spiral valve in the intestine. Specialized characters are
absence of ossification in the cranial cartilage, premaxillae and maxillae and presence of dental plates on the jaws. Lepidosiren shows resemblance with Amphibia in internal nostrils, lung respiration and autostylic suspension. autostylic suspensorium show similarity with Amphibians.