Tag Archive: bonytongues


TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Osteoglossiformes
Family: Osteoglossidae (Bonytongues)

Genus/species: Osteoglossum bicirrhosum

 GENERAL CHARACTERISTICS: The silvery body is covered with very big scales, and the dorsal and anal fins are almost fused with the caudal fin. They have a bony tongue with a huge oblique mouth and oral bones bearing teeth, including the jaw, palate, tongue and pharynx. Two barbels are found at the end of the lower jaw.

The Silver Arawana is a large fish with a length up to 1.2 m (4 ft) and weight up to 4.6 kg (10 lbs).

Silver ArawansIMG_1974

DISTRIBUTION/HABITAT: This fish is found in tropical freshwater, and is especially prevalent in flooded areas and swamps in the Amazon River system. It is capable of adapting to environments with low oxygen levels.

DIET IN THE WILD: O. bicirrhosum feed mainly on crustaceans, insects, smaller fishes, and other animals that float on the water; its upturned mouth is an adaptation for surface feeding. Sometimes called the “water monkey” for its jumping abilities, Silver Arawana have been known to leap some 2 m (6.5 ft) out of the water to pluck a surprised and often doomed insect or bird from overhanging branches. Bats and snakes have also been occasionally found as stomach contents.

REPRODUCTION: Interestingly, the Arawana male is a mouth brooder carrying eggs, larvae, and young juveniles in his mouth for about 2 months.

CONSERVATION: IUCN Red List; Not Evaluated
CITES: No special status

REMARKS: Arawana provide the largest source of protein in comparison to other Amazon fish. Also, because of its low-fat content, they are considered the most digestible and least likely to bring about sickness.

References

California Academy of Sciences Steinhart Aquarium Amazon Flooded Tunnel 2018

Ron’s flickr https://www.flickr.com/photos/cas_docents/15007803584/in/album-72157620568438047/

Ron’s WordPress shortlink   http://wp.me/p1DZ4b-a0

fishbase www.fishbase.org/summary/Osteoglossum-bicirrhosum.html

 Animal Diversity web animaldiversity.ummz.umich.edu/accounts/Osteoglossum_bici…

 “It’s Easy Being Green” Docent Course. California Academy of Sciences 2014

 

 

 

TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii (ray-finned fishes)
Order: Osteoglossiformes (Bony tongues)
Family: Arapaimidae (Bonytongues)

Genus/species: Arapaima gigas

GENERAL CHARACTERISTICS: Usually grey to green in color with red flecks on the scales towards the tail and reddish-orange color of the filleted flesh. They are heavy with an elongated body with very large scales. There are also two symmetrical fins on either side of the body at the posterior end. The arapaima has a tongue with sharp, bony teeth that together with teeth on the roof of its palate are involved in disabling and shredding prey

It is one of the largest freshwater fishes in the world (length up to 450cm (14 feet in the 1800’s) Common length 200 cm (6.75 feet). Weight up to 133 kg. (292 lbs) In the 1800s specimens to 200 kg (440 lbs) were reported. 

DISTRIBUTION/HABITAT: Tropical. Amazon River and its tributaries in freshwater flooded areas dense with aquatic vegetation and shore plants. Much of the water that comprises the pirarucu’s habitat is also oxygen deficient, as it is located in swampy areas of the rainforest.

DIET IN THE WILD: Specialized for surface feeding with their up turned mouths. Adults prey on fish at the surface; suck smaller fish into the mouth, then crush pre against the roof of its mouth using its tooth-covered bony tongue. Like its close relative the arawana, it can leap from the water to snatch a bird or even a monkey from an overhanging branch.

ArapaimaGigasIMG_2727

REPRODUCTION: Sexually mature at the age of five years old. Builds a nest of about 15 cm (6 inches) depth and 50 cm (20 inches) width in sandy bottoms. Guards the eggs and the young. Adults have the ability to exude a pheromone from their head to attract offspring and keep them in close proximity.

MORTALITY and LONGEVITY: Preyed upon by humans. Life spans of 15 to 20 years in captivity .

CONSERVATION: IUCV Red List Data deficient. CITES Appendix II. Heavily exploited as a commercial fish throughout the Amazon. Populations have been greatly reduced during the past 200 years Commercial fishing of arapaima was banned in Brazil outside of a limited number of sustainable reserves, but illegal fishing still continues.

REMARKS: Indigenous people utilize the scales and bones. The bony or toothed tongue was once used as a seed grater to make drink powders. Its scales were used as scrappers.

In addition to gills, it has a modified and enlarged swim bladder, composed of lung-like tissue, which enables it to extract oxygen from the air. It is an obligate air breather, well adapted to oxygen-deficient waters gulping air every 10–15 minutes when oxygen levels are low.

Often referred to as the largest freshwater fish; some freshwater catfishes and sturgeon may challenge this “record.”

References

California Academy of Sciences Steinhart Aquarium Amazon Flooded Tunnel, 2018

Ron’s WordPress shortlink  wp.me/p1DZ4b-a7

Ron’s flickr   https://www.flickr.com/photos/cas_docents/3258200203/in/album-72157620568438047/

 fishbase  www.fishbase.org/summary/Arapaima-gigas.html

Arkive www.arkive.org/arapaima/arapaima-gigas/

 U. of Michigan Animal Diversity Web  animaldiversity.ummz.umich.edu/accounts/Arapaima_gigas/

National Geographic. www.nationalgeographic.com/environment/freshwater/arapaima/

 Encyclopedia of Life  eol.org/pages/204868/details

 

 


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