Calloused catfish
| Calloused catfish | ||||||||||||
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Calloused catfish ( Callichthys callichthys ) |
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| Scientific name | ||||||||||||
| Callichthys callichthys | ||||||||||||
| ( Linnaeus , 1758) |
The callous catfish ( Callichthys callichthys ) is a freshwater fish species from the armored and callous catfish family (Callichthyidae), which occurs in northern and central South America east of the Andes and south to the Río de la Plata and on Trinidad .
features
Calluses reach a maximum length of 18 cm, a maximum weight of 80 g and have a cylindrical, elongated body that has an almost constant body height over its entire length, while the body width decreases towards the rear. The head is broad and flattened dorsoventrally. The eyes are small. Above the midline of the body there are 26 to 29 bone plates, below there are 25 to 28 and 18 to 23 bone plates separate the dorsal fin from the adipose fin . Calluses are brownish, dark olive green or dark gray in color and shimmer slightly bluish or purple. The fins are darkly spotted and can show an orange or reddish border. Males are usually stronger in color and have a stronger ventral spine.
- Fin formula : dorsal 1/6, anal 1/5, pectoral 1/7, ventral 1/5.
Way of life
Calluses are nocturnal and occur in a wide variety of water types ( pH 5.8–8.3), even in very low-oxygen ones. If the water bodies dry out, the animals can crawl short distances over land with the help of their powerful fins and their ability to take in air swallowed with their intestines in order to find new bodies of water. Calluses eat insects, small fish and vegetable matter. To reproduce, the male builds a foam nest about 8 to 10 cm in diameter under leaves floating on the surface of the water ( floating ferns , Riccia fluitans , fallen leaves) . To do this, it takes in air, swimming with its belly up to the surface of the water, and then spits the small bubbles covered with saliva under the nest. After each mating act, the female transports the eggs in the supine position in the folded pelvic fins into the nest. The foam nest is guarded by the male. The fry hatching after 4 to 6 days initially feed on rotifers and later on small crustaceans and insects.
Systematics
The callous catfish was already described in 1758 by Carl von Linné , the founder of modern taxonomy , in his Systema Naturae as Silurus callichthys . It is the type species of the genus Callichthys , which was established in 1777 by the Austrian naturalist Giovanni Antonio Scopoli , and which remained monotypical for a long time , but actually represents a swarm of very similar species. To date (mid-2015) three other valid species have been described, 1999 Callichthys fabricioi from the catchment area of the Río Cauca in Colombia, 2004 Callichthys serralabium from the Upper Orinoco in Venezuela and the upper Rio Negro in northern Brazil and 2006 Callichthys oibaensis from the Río Magdalena , also in Colombia.
literature
- Hans-Jochim Franke: Handbook of Welskunde. Urania-Verlag, 1985.
- Günther Sterba : The world's freshwater fish. 2nd Edition. Urania, Leipzig / Jena / Berlin 1990, ISBN 3-332-00109-4 .
Individual evidence
- ^ Reis, Roberto E. 1996. Callichthys in The Tree of Life Web Project
- ↑ Callichthys fabricioi on Fishbase.org (English)
- ↑ Callichthys serralabium on Fishbase.org (English)
- ↑ Callichthys oibaensis on Fishbase.org (English)
Web links
- Calluses on Fishbase.org (English)