Gill slit eels

from Wikipedia, the free encyclopedia
Gill slit eels
East Asian gill slit eel (Monopterus albus)

East Asian gill slit eel ( Monopterus albus )

Systematics
Sub-cohort : Neoteleostei
Acanthomorphata
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Gill slit eels (Synbranchiformes)
Family : Gill slit eels
Scientific name
Synbranchidae
Bonaparte , 1838

The gill slit eels (Synbranchidae ( Gr .: Syn, Symphysis , "brangchia" = gill)), formerly also known as short-tailed eels , are a family of eel-like, highly specialized bony fish. They occur disjointly in tropical and subtropical fresh waters in Central and South America, Africa ( Sierra Leone to Ivory Coast ), Asia, New Guinea and Northern Australia.

features

Gill slit eels have an eel-like body, without pectoral or pelvic fins. The pectoral fins of some species are still present in the early youth stages. The dorsal and anal fins are only rudimentary and have become a fleshy ridge without spines. A caudal fin is only present in Macrotrema caligans , rudimentary or completely absent in the other species. With the exception of the species of the subgenus Amphipnous of Monopterus , all gill slit eel species are scaleless. The eyes are small, in some species they are under the skin so that the animals are blind. The front and rear nostrils are wide apart. The palatoquadratum (the upper jaw) is attached to the skull (neurocranum) in two places, at the front, in the nasal region, and at the back with the mediation of the hyomandibel (mandibular stem). This makes the gill slit eels the only Teleostei with an amphistylic jaw suspension. The gill openings are small and are located as a pore or small slit in the throat region. Only Macrotrema caligans have normal-sized gill slits that have grown together below the throat. Gill slit eels can breathe air and take in the air through vascularized membranes in the throat, lung-like pouches in the gill cavity or a special section of the hindgut. The latter release the used air through the anus. The number of Branchiostegal rays is four to six, those of the vertebrae 98 to 188, of which 51 to 135 are trunk vertebrae. There are no ribs or a swim bladder . Most gill-slit eels are protogyne (female reproductive organs mature first) hermaphrodites . They become 8.5 centimeters to 1.5 meters long.

Way of life

Gill eels often live in swampy habitats, many also in brackish water . They move partially digging in the mud. Some species are specialized cave dwellers. They regularly come to the surface of the water to breathe, or they stand vertically in the water, with their snouts on the surface of the water and their angled tail on the bottom of the water. They survive dry periods buried in the mud with reduced oxygen demand and breathing (summer sleep). In some species brood care has been observed, they build a foam nest in which they lay the eggs. Gill slit eels feed on worms, insects and their larvae, small crustaceans, fish and frogs.

Internal system

literature

Web links

Commons : Synbranchidae  - collection of images, videos and audio files