Cynodon (fish)

Cynodon, is a genus of freshwater ray-finned fishes belonging to the family Cynodontidae, the dogtooth characins. These piscivorous fishes are found in tropical SOuth America.

Cynodon
Cynodon gibbus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Characiformes
Family:	Cynodontidae
Genus:	Cynodon (Spix, 1829)[1]
Type species
Cynodon gibbus Spix & Agassiz, 1829[1]
Synonyms[1]
Cynodon Cuvier, 1829 Camposichthys Travassos, 1946

Taxonomy

Cynodon was first proposed as genus in 1829 by the French zoolgist Georges Cuvier with its only species being Hydrocynus scomberoides, this name was also proposed by Johann Baptist von Spix in 1829 with Cynodon gibbus given as the only species. Cuviers's name is technically a senior synonym of Hydrolycus but the name was suppressed in the IUCN Opinion 2012.^[1] Cynodon gibbus was first formally described as Raphiodon gibbus by Spix and Louis Agassiz in 1829 with its type locality given as Lago Manacapuru in the Amazonas State, Brazil. However, in the plate preceding the description in Selecta genera et species piscium : quos in itinere per Brasiliam annis MDCCCXVII-MDCCCXX jussu et auspiciis Maximiliani Josephi I it was named as Cynodon gibbus and the IUCN Opinion 2012 confirmed that this was the valid name for this taxon.^[2] This taxon is the type genus of the family Cyonontidae which was named by Carl H. Eigenmann in 1903.^[3] This family Cyodontidae belongs to the suborder Characoidei of the order Characiformes.^[4]

Species

Cynodon has the following valid species classified within it:^[2]

• Cynodon gibbus (Spix & Agassiz, 1829)
• Cynodon meionactis Géry, Le Bail & Keith, 1999
• Cynodon septenarius Toledo-Piza, 2000

Etymology

Cynodon places the Greek kynos, meaning "dog", in its genitive case as kyon, with odon, meaning "tooth". This is a reference to the pair of robust canine-like teeth poseessed by these fishes.^[5]

Characteristics

Cynodon is told apart from the other two genera in its family by the possesion of a comparatively long anal fin with an fin ray count of at least 60 brached rays, the other two genera have less than 50. The orihgin of the anal fin is located isat the centre of the body while in the other two genera it is towards the rear of the body.^[6] The species in this genus are of similsr sized, all having maximum lengths of around 30 to 32 cm (12 to 13 in).^[7]

Distribution

Cyonodon dogtooth tetras are found in northern South America in the coastal rivers of the Guianas and in thedrainag basisn of the Amazon and Orinoco, in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela.^[6]