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Acerinae
''Gymnocephalus'' is a genus of ray-finned fishes from the family Percidae, which includes the perches, pike-perches and darters. They are from the Western Palearctic area, although one species, ''Gymnocephalus cernua'' has been accidentally introduced to the Great Lakes region where it is regarded as an invasive species. They have the common name "ruffe" and resemble the true perches in the genus ''Perca'', but are usually smaller and have a different pattern. Characteristics The species within the genus ''Gymnocephalus'' have a number of characters in common including that their dorsal fins are not completely separate, they have enlarged canals extending from the lateral line on their heads, the preorbital bone covers the maxillary bone, presence of setiform or bristle-like teeth, having very few or no vomerine and palatine teeth and the possession of three paired bones in the neck, known as extrascapulars, in their lateral line system, of which, two are simple tubes. Species T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Percidae
The Percidae are a family of ray-finned fish, part of the order Perciformes, which are found in fresh and brackish waters of the Northern Hemisphere. The majority are Nearctic, but there are also Palearctic species. The family contains more than 200 species in 11 genera. The perches, and their relatives are in this family; well-known species include the walleye, sauger, ruffe, and three species of perch. However, small fish known as darters are also a part of this family. Characteristics The family is characterised by having the dorsal fin split into two which are normally separated or have a narrow connection, although this is wider in the genus ''Zingel'', the front section contains the spines and the rear section contains the soft rays. The anal fin contains 1 or 2 spines, if there is a second spine it is typically weak. The pelvic fins are placed on the thorax and have a single spine and 5 soft rays. They also have skeletal synapomorphies. The maximum size attained in in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |