Gadopsis
| Gadopsis | ||||||||||||
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Gadopsis marmoratus |
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| Scientific name | ||||||||||||
| Gadopsis | ||||||||||||
| Richardson , 1848 |
Gadopsis is a genus of unusual freshwater fish within the cod familycalled Freshwater Blackfishes in Australia. The genus name Gadopsis was given because of the external similarity of the fish with the cod ( Gadus + Gr .: "Opsis" = appearance).
features
The fish in the genus Gadopsis grow to be 30 to 60 cm tall and weigh up to 5 kg, with an elongated and fairly slim physique. The belly fins are located in front of the pectoral fins, on the "neck", and consist of a single, branched fin ray . The dorsal fin extends over the entire back, the scales are small and the side line is well defined.
Way of life
The fish are nocturnal, loyal to their location and inhabit the bottom of the water. They carnivorously feed on insects, crustaceans, worms, small fish and fish eggs. The spawning season is in the Australian spring or summer. The females then lay 20 to 500 eggs in a clump in a crevice or a hollow dead wood, depending on their size. The larvae hatch after about 16 days, but still adhere to the egg shell for up to three weeks. The male guards the clutch until the larvae swim freely. With about 15 centimeters in length, after two or three years, the fry become sexually mature.
Systematics and types
The endemic fish of the genus Gadopsis in the south-east of Australia and in the north of Tasmania were at times considered as an independent family (Gadopsidae), but today mostly classified in the family of codfish (Percichthyidae), where they presumably occupy a basal position. The species Bostockia porosa is seen as the closest relative .
There are two types scientifically described:
- Gadopsis bispinosus Sanger, 1984 , Two-spined Blackfish, becomes a maximum of 30 cm long
- Gadopsis marmoratus Richardson, 1848 , River Blackfish, becomes a maximum of 60 cm long
In a genetic study (Hammer et. Al, 2014), in which genetic material from the cell nucleus as well as from the mitochondria was used, 200 specimens of the two nominal taxa mentioned above were examined from 69 sites in the entire distribution area. It could be demonstrated that the northern and southern populations of Gadopsis marmoratus , which differ morphologically, are also genetically very different. Each of these three clades within Gadopsis could in turn be differentiated into two populations ( cryptic species ), which are candidates for new species in the genus Gadopsis .
literature
- G. Allen, S. Midgley, M. Allen: Field Guide to the Freshwater Fishes of Australia . 2nd Edition. Western Australian Museum, Perth 2003, ISBN 0-7307-5486-3 , pp. 204-206 .
- M. Hammer, P. Unmack, M. Adams, T. Raadik, J. Johnson: A multigene molecular assessment of cryptic biodiversity in the iconic freshwater blackfishes (Teleostei: Percichthyidae: Gadopsis) of south-eastern Australia . In: Biological Journal of the Linnean Society . tape 111 , 2014, p. 521-540 .
Web links
- Gadopsis on Fishbase.org (English)