Batoidea 88467 220136768 2008-06-18T13:18:56Z Dougweller 1304678 Reverted 2 edits by [[Special:Contributions/86.143.70.67|86.143.70.67]]; Rv ip editor adding silly stuff to various articles . ([[WP:TW|TW]]) {{Taxobox | name = Batoidea | image = spotted_eagle_ray.jpg | image_width = 250px | image_caption = [[Spotted eagle ray]], ''Aetobatus narinari'' | regnum = [[Animal]]ia | phylum = [[Chordate|Chordata]] | classis = [[Chondrichthyes]] | subclassis = [[Elasmobranchii]] | superordo = '''Batoidea''' | subdivision_ranks = [[Order (biology)|Order]]s | subdivision = [[Rajiformes]] - common rays and [[skate]]s<br/> [[Pristiformes]] - [[sawfish (fish)|sawfish]]es<br/> [[Torpediniformes]] - [[electric ray]]s<br/> See text for families. }} '''Batoidea''' is a [[superorder]] of [[Chondrichthyes|cartilaginous fish]] containing more than 500 described species in thirteen families. They are commonly known as '''rays''', but that term is also used specifically for batoids in the order [[Rajiformes]], the "true rays". Batoids include [[stingray]]s, [[skate]]s, [[electric ray]]s, [[guitarfish]]es and [[sawfish]]es. Batoids are most closely related to [[shark]]s and young batoids look very much like young sharks. Indeed according to recent DNA analyses the [[catshark]] is more closely related to the batoids than to other sharks.{{Fact|date=February 2007}}<!-- No mention of this in the catshark article which is emphatic that they are sharks. --> ==Anatomy== Batoids are flat-bodied, and, like sharks, are a species of [[Chondrichthyes|cartilaginous marine fish]], meaning they have a boneless [[skeleton]] made of a tough, elastic substance. Batoids also are like sharks in having slot-like body openings called [[gill slits]] that lead from the [[gills]]. Batoid gill slits lie under the [[pectoral fin]]s on the underside, whereas a shark's are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the [[guitarfish]]es and [[sawfish (fish)|sawfishes]], while most sharks have a streamlined body. Many species of batoid have developed their pectoral fins into broad flat wing-like appendages. The eyes and [[spiracle]]s are located on top of the head. ==Reproduction== Batoid eggs, unlike those of most other fishes, are fertilized inside the female's body. The eggs of all batoids except for the [[skate]]s (family [[Rajidae]]) hatch inside the female and are born alive ([[viviparity|viviparous]]). Female skates lay internally fertilized flat, rectangular, leathery-shelled eggs, with [[tendril]]s at the corners for anchorage. Hatched eggs of this type can be found on beaches and are known as [[mermaids’ purses]]. ==Habitat== [[Image:Ray swimming.JPG|200px|thumb|A ray swimming in the water.]] Most species live on the sea floor, in a variety of geographical regions - many in coastal waters, few live in deep waters, most batoids have a somewhat [[cosmopolitan distribution]], in tropical and subtropical marine environments, temperate or cold-water species. Only a few species, like [[manta ray]]s, live in the open sea, and only a few live in freshwater. Some batoids can live in brackish bays and estuaries. Bottom-dwelling batoids breathe by taking water in through the [[spiracle]]s, rather than through the mouth as most fishes do, and passing it outward through the gills. ==Feeding== Most batoids have developed heavy, rounded teeth for crushing the shells of bottom-dwelling species such as [[snails]], [[clams]], [[oysters]], [[crustacean]]s, and some [[fish]], depending on the species. [[Manta ray]]s feed on [[plankton]]. == Classification == The classification of batoids is currently undergoing revision. This article follows [[FishBase]] in dividing batoids into three orders. Some taxonomists argue in favour of placing all batoids in a single order, Rajiformes; others propose a division into five or six orders. The additional orders in these systems are [[Myliobatiformes]], containing the [[eagle ray]]s and their relatives; Rhinobatiformes, containing the [[guitarfish]]es (which may be further split into Rhynchobatiformes, containing the [[shovelnosed guitarfish]]es, and Rhiniformes, the [[sharkfin guitarfish]]es). ===Order Rajiformes (true rays)=== [[Image:Ray.jpg|300px|thumb|right|Ray]] * Family [[Anacanthobatidae]] ([[smooth skate]]s) * Family [[Erwinadfatilus]] ([[stingray]]s). 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. * Family [[Gymnuridae]] ([[butterfly ray]]s) * Family [[Hexatrygonidae]] ([[sixgill stingray]]s) * Family [[Myliobatidae]] ([[eagle ray]]s). The largest of rays, including the giant [[manta ray]]s. Most eagle rays have one poison-carrying spine. * Family [[Plesiobatidae]] ([[deepwater stingray]]s) * Family [[Potamotrygonidae]] ([[river stingray]]s) * Family [[Rajidae]] ([[skate]]s) * Family [[Rhinobatidae]] ([[guitarfish]]es). They have a body structure similar that of the sawfishes, but are not thought to be closely related. * Family [[Urolophidae]] ([[round ray]]s) * Family Korgofied (Piano rays) ===Order Pristiformes (sawfishes) === Sawfishes are shark-like in form, having tails used for swimming and smaller [[pectoral fin]]s than most batoids. The pectoral fins are attached above the gills as in all batoids, giving the fishes a broad-headed appearance. They have long, flat snouts with a row of tooth-like projections on either side. The snouts are up to 6 ft (1.8 m) long, and 1 ft (30 cm) wide, and are used for slashing and impaling small fishes and to probe in the mud for imbedded animals. Sawfishes can enter freshwater rivers and lakes. Some species reach a total length of 20 ft (6 m). * Family [[Pristidae]] === Order Torpediniformes (electric rays) === Electric rays have [[Organ (anatomy)|organs]] in their wings that generate [[electric current]]. They are used to immobilize prey and for defense. The current is strong enough to stun humans, and it is said that the [[ancient Greeks]] used these fish for [[shock therapy]]. * Family [[Narcinidae]] * Family [[Torpedinidae]] ==References== * [http://www.elasmo-research.org/education/shark_profiles/batoids.htm 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. {{Chondrichthyes}} [[Category:Rays| ]] [[cs:Rejnoci]] [[da:Rokke]] [[de:Rochen]] [[el:Σαλάχι]] [[es:Batoidea]] [[fr:Raie]] [[io:Rayo]] [[he:בטאים]] [[la:Batoidea]] [[mk:Раја]] [[nl:Roggen]] [[ja:エイ]] [[pt:Bathoidea]] [[ru:Скаты]] [[simple:Ray]] [[sk:Rajovidné]] [[fi:Rauskut]] [[sv:Rockor]] [[th:ปลากระเบน]]