Oxyeleotris

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Oxyeleotris
Marble goby (Oxyeleotris marmorata), the type species of the genus and largest species of the genus and the goby-like

Marble goby ( Oxyeleotris marmorata ), the type species of the genus and largest species of the genus and the goby-like

Systematics
Acanthomorphata
Spinefish (Acanthopterygii)
Perch relatives (Percomorphaceae)
Order : Gobies (Gobiiformes)
Family : Butidae
Genre : Oxyeleotris
Scientific name
Oxyeleotris
Bleeker , 1874

Oxyeleotris is a genus of secondary freshwater fish in the Butidae family. Its scientific name comes from the Greek ; "Oxys" means "pointed" and indicates the tapering head profile, Eleotris is a genus of sleeper gobies (to which the Butidae were previously assigned). The type of genus is the marble goby , Oxyeleotris marmorata (Bleeker, 1852).

distribution

The genus occurs from Laos and Thailand to the Philippines and Indonesia to the Carolines and northern and northwestern Australia . The majority of the species live east of the Wallace Line , west of it, on Sumatra , Kalimantan , the Malay Peninsula in Thailand and the Mekong river basin , only three species live. They are unlikely to stand up to competition from primary freshwater fish, especially carp and catfish . In New Guinea , Oxyeleotris is the most species-rich genus of the Butidae with eight species. Adult stages of all species only occur in freshwater and in all species whose reproduction has been researched, the larvae also live in freshwater.

features

Oxyeleotris species have an elongated body that is massive in growing species and is covered by small, usually ctenoid scales. In their coloring, brown tones and less contrasting darker drawing elements dominate. On the upper base of the caudal fin there is often a brightly rimmed black eye spot . The front body is approximately cylindrical in cross-section, the head is broad and covered with cycloid scales almost to the mouth . The mouth is large and extends back under the center of the eye or under the back of the eye. The front nostrils end in tubes that reach down to the upper lip. Oxyeleotris species are 4 to 65 centimeters long. From other genres of Butidae the genus differs oxyeleotris by the arrangement of the sensory channel system , especially the cross series, on the sides of the head. The genus Bostrychus also has a similar sensory canal system , which some authors have regarded as a synonym with Oxyeleotris, but differs from Oxyeleotris and other genera of the Butidae in the dentition of the vomer , the shape of the dorsal fin, the scaling through cycloid scales and other features . The first dorsal fin of the Oxyeleotris species is often remarkably small, has six spines and is never higher than the second dorsal fin. The males differ from the females by having a flatter, narrower and shorter urogenital papilla.

Fin formula : dorsal 1 VI, dorsal 2 I / 8–14, anal I / 7–12. Scale formula : SL 50–100.

Way of life

Oxyeleotris species live as territorial loners in stagnant to slowly flowing waters with sandy or muddy ground. They make extensive use of hiding places such as aquatic plants, sunken wood or leaves and overhanging banks. The marble goby digs into the ground. All Oxyeleotris species carnivore feed on invertebrates such as freshwater shrimp or on smaller fish. In aquariums, O. urophthalmus swallowed slender fish half their body length.

Reproduction

The reproductive biology of the genus is known from aquarium observations of four species. The marble goby spawns on the ceiling of spacious caves. A clutch contains up to 30,000 eggs. The three millimeter long larvae hatch after three days at a temperature of 27 ° C. Initially, her swim bladder is still without function and the jaw cannot be moved. After four to five days, with a length of 4 mm, the yolk supply, on which larvae fed in their first days of life, is used up, the swim bladder is filled and the larvae, which are now free-swimming, begin to eat.

species

The genus currently comprises 17 scientifically described species:

literature

  • Hans Horsthemke: Some sleeper gobies from the subfamily Butinae. In: DATZ . Vol. 46, 1993, ISSN  1616-3222 , pp. 242-249.
  • Hans Horsthemke: Oxyeleotris. In: Claus Schaefer, Torsten Schröer (Hrsg.): The large lexicon of aquaristics. Eugen Ulmer, Stuttgart 2004, ISBN 3-8001-7497-9 , p. 734.

Web links

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