Gymnocephalus is a genus of ray-finned fishes from the family Percidae, which includes the , pike-perches and Etheostomatinae. 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 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
are not completely separate, they have enlarged canals extending from the
lateral line on their heads, the preorbital bone covers the
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
There are currently five recognized species in this genus:
Taxonomy
Gymnocephalus was created by the
German people physician and
naturalist Marcus Elieser Bloch (1723–1799) with
Perca schraester as the
type species. It has traditionally been placed in the
subfamily Percinae alongside the true
perch of the genus
Perca.
[ However, Gymnocephalus appears to be the sister taxon to both the Percinae and to the Luciopercinae.][ The 5th edition of Fishes of the World treats Gymnocephalus as the only genus in the Monotypy subfamily Acerinae,]
The name of the genus is a compound of the Greek language gymno meaning "naked" and kephalos meaning "head".
Geographic distribution
The species in the genus Gymnocephalus are found in Europe. One species, G. cernua, originating from the river Elbe in Germany, was accidentally introduced to North America in ballast water near the mouth of the St Louis River in Lake Superior.[ This species has also been introduced outside of its native range in Europe.]
External links
