|
|
|
|
|
Characiformes Acestrorhynchidae Anostomidae - Headstanders Characidae - Characins and tetras Citharinidae Ctenoluciidae - Pike-characids Curimatidae Erythrinidae - Trahiras Gasteropelecidae - Freshwater hatchetfishes Hemiodontidae Hepsetidae Lebiasinidae The Characiformes are an order of ray-finned fish, comprising the characins and their allies. There are a few thousand different species, including the well-known piranha and tetras. These belong within the superorder Ostariophysi, a group mainly distinguished by the presence of a Weberian apparatus, a series of bony parts connecting the swim bladder and inner ear. Superficially the Characiformes somewhat resemble their relatives the minnows. The most noticeable differences are the presence of a small fleshy adipose fin between the dorsal fin and tail, and the presence of teeth within the mouth, though there are exceptions to both of these. Barbels are always absent and the body is almost always covered in well-defined scales. Characins are found in tropical lakes and rivers throughout most of South America, Central America, and central Africa. This and other evidence suggests they first diversified during the Cretaceous period, though fossils are poorly known. A few characins become quite large, and are important as food or game. Most, however, are small shoaling fish. Many species are popular in aquaria thanks to their bright colors, general hardiness, and tolerance towards other fish in community tanks. Originally the characins were all grouped within a single family, the Characidae, which was included in the Cypriniformes. Since then about 15 different families have been separated out. However, classification varies somewhat, and it appears the circumscribed Characidae are still polyphyletic.
|  | prince albert aspen, colorado leadville, colorado colorado gold rush simon de montfort, 6th earl of leicester autogynephilia camille saint sans dressage eventing american correctional association lobbying
| american legislative exchange council prison lockport state legislature brazoria county, texas clark county, washington clark county, nevada graz cavefish merlucciidae empress maud
| elizabeth ii of the united kingdom pejorative battle of spotsylvania court house eleftherios venizelos airport tigard, oregon battle of cold harbor washington county, oregon guanxi corvallis, oregon salem, oregon characidae
| stock phrase ass randal l. schwartz go strategy and tactics basidiomycota ascomycota omega chess history of anatomy central city, colorado idaho springs, colorado social justice
|
|
 |
|
| Copyright 2005-2009 OnPedia.com. All Rights Reserved |
|
|