Polypterus senegalus

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Senegal bichir
Polypterus senegalus senegalus.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Subclass: Chondrostei
Order: Polypteriformes
Family: Polypteridae
Genus: Polypterus
Species: P. senegalus
Binomial name
Polypterus senegalus
Cuvier, 1829

The Senegal bichir, Polypterus senegalus, also known as the gray bichir and Cuvier's bichir, is sometimes called the "dinosaur eel" (a misnomer, as the creature is not an eel) and also known as "dragon fish" at many local pet chains. It is a prototypical species of fish in the Polypterus genus, meaning most of its features are held across the genus.

Appearance[edit]

The body is long and about as deep as it is wide. A serrated dorsal fin runs along most of the body until it meets the caudal fin. The pectoral fins attach just behind and below the gill openings, and are the primary means of locomotion, providing a slow, graceful appearance. P. senegalus is smaller than other bichirs, reaching about 35.5 cm (14 in).

The head is small and lizard-like, with a gaping mouth and small eyes on either side. Since its eyesight is poor, the bichir primarily hunts by smell. External nostrils protrude from the nose of the fish to enable this.

The fish has a pair of primitive lungs instead of a swim bladder, allowing it to periodically gulp air from the surface of the water. In the aquarium, bichirs can be observed dashing to the surface for this purpose. Provided the skin remains moist, the creature can remain out of the water for nearly indefinite periods of time.

This bichir's skin serves as a particularly effective armor,[1] and has been studied as a model for personal armor for better combinations of protection and mobility.[2]

A juvenile bichir forages for food

Subspecies[edit]

Three subspecies of P. senegalus are recognized: P. s. senegalus, P. s. meridionalis, and a further unnamed subspecies.

  • P. s. senegalus grows to about 80 cm (20 in) in the wild, and 48 cm (12 in) in captivity. It is a uniform brownish-grey to olive color on the dorsal surface, and the ventral surface is whitish. No banding occurs on adults, but very young juveniles show three horizontal bands. The upper jaw is slightly longer than lower jaw. It has eight to 11 dorsal finlets.
  • P. s. meridionalis grows to about 110 cm (28 in) in the wild, and 56 cm (14 in) in captivity. It is a uniform olive-grey color on the dorsal surface. The upper and lower jaws are about the same length. It has 9 or 10 dorsal spines. P. s. meridionalis may be a regional variant of P. s. senegalus.

Captivity[edit]

Bichirs are predatory fish; in captivity they will take any live or dead animal that can be swallowed or broken apart and then swallowed. Only its lack of speed prevents a bichir from emptying an aquarium of smaller fish; the pectoral fins only allow for slow cruising, and while it can achieve amazing bursts of speed, it cannot catch fish of average speed. Given enough time, any fish that can fit in the bichir's mouth will be eaten; this fish should not be kept with any other fish smaller than three inches. It will also bite fins of other fishes if it can.

Senegal Bichir can be acclimated to a terrestrial environment allowing for evolutionary physical changes such as the ability to walk on land.

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