Rajiformes

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Rajiformes is the order of true rays and skates, flat-bodied cartilaginous fishes related to sharks.

Classification

There are several proposed classifications of fish in the order Batoidea. In some classifications the order Rajiformes is split into two to four orders: in these classifications Rajiformes contains only the skates, with the stingrays, eagle rays and their relatives in Myliobatiformes and the guitarfishes in Rhinobatiformes (which may be further split into Rhynchobatiformes, containing the shovelnosed guitarfishes, and Rhiniformes, the sharkfin guitarfishes).

Anacanthobatidae (smooth skates)
Dasyatidae (stingrays). Named for the venomous spines along the tail; these contain a poison that causes pain and may cause symptoms such as nausea, vomiting, fever, chills, muscle cramps, tremors, paralysis, fainting, seizures, elevated heart rate, and decreased blood pressure (depending on the species). In addition, some species' toxins can be fatal to humans.
Gymnuridae (butterfly rays)
Hexatrygonidae (sixgill stingrays)
Myliobatidae (eagle rays). The largest of rays, including the giant manta rays. Most eagle rays have one poison-carrying spine.
Plesiobatidae (deepwater stingrays)
Potamotrygonidae (river stingrays)
Rajidae (skates)
Rhinobatidae (guitarfishes). They have a body structure similar that of the sawfishes, but are not thought to be closely related.
Urolophidae (round rays)

References

["Rajiformes"]. FishBase. Ed. Ranier Froese and Daniel Pauly. January 2006 version. N.p.: FishBase, 2006.
[Batoids: Sawfishes, Guitarfishes, Electric Rays, Skates, and Sting Rays]
J. D. McEachran, K. A. Dunn, T. Miyake (1996). "Interrelationships of the batoid fishes (Chondrichthyes: Batoidea)". In Interrelationships of Fishes, Academic Press.

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