Difference between revisions of "Ray" - New World Encyclopedia

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Rajiformes

Spotted eagle ray, Aetobatus narinari

Scientific classification

Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Subclass:	Elasmobranchii
Superorder:	Batoidea
Order:	Rajiformes

Families

Anacanthobatidae
Dasyatidae
Gymnuridae
Hexatrygonidae
Myliobatidae
Plesiobatidae
Potamotrygonidae
Rajidae
Rhinobatidae
Urolophidae

In zoology, ray is the common name for cartilaginous fish comprising the order Rajiformes (or Batoidea), characterized by enlarged and flat pectoral fins continuous with the head, no anal fin, eyes on the dorsal surface, and a narrow tail. The skates comprise a family, Rajidae, within the Rajiformes, and thus can be considered a type of ray. For those taxonomic systems recognizing Batoidea as a superorder, ray may also be used as a term for members of this superorder.

Overview

The Chondrichthyes or "cartilaginous fishes" are jawed fish with paired fins, paired nostrils, scales, two-chambered hearts, and skeletons made of cartilage rather than bone. They are divided into two subclasses: Elasmobranchii (sharks, rays, and skates) and Holocephali (chimaera, sometimes called ghost sharks).

The Elasmobranchii are sometimes divided into two superorders, Selachimorpha (sharks) and Batoidea or Batidoidimorpha (rays, skates, sawfish). Nelson (1994) notes that there is growing acceptance of the view that sharks and rays together form a monophyletic group (superorder Euselachii), and sharks without rays are a paraphyletic group.

There are diverse taxonomies, and Batoidea is variously considered a superorder (eg., Taxonomicon 2007; Frisk et al. 2005; Systema Naturae 2000 2007; Rocco et al. 2007) or an order (ITIS 2007; Froese and Pauly 2005). As a superorder, Batoidea typically includes three orders: Rajiformes (true rays), Torpediniformes (electric rays), and Pristiformes (sawfishes). Some recognize additional orders such as Myliobatiformes (eagle rays) and Rhinobatiformes (guitarfishes).

Description

True rays, including skates, are placed in the order Rajiformes. Members of Rajiformes are characterized by the anterior edge of the pectoral fin, which is greatly enlarged, being attached to the side of the head anterior to the gill openings (Nelson 1994). They also have ventral gill openings, and the eyes and spiracles are on the dorsal surface (Nelson 1994). The body is normally strongly depressed and in most water for breathing is taken in through the spiracle rather than the mouth. In addition, members of Rajiformes lack an anal fin and lack a nictitating membrane with the cornea attached directly to the skin around the eyes (Nelson 1994).

Most rays give birth to live young, but the skates in family Rajidae are characterized by eggs that are encased in a horny capsule with four long tips (Nelson 1994).

References
ISBN links support NWE through referral fees

Taxonomicon. 2007. Superorder Batoidea. Taxonomicon. Retrieved December 18, 2007.

Frisk, M. G., T. J. Miller, and N. K. Dulvy. 2005. Life histories and vulnerability to exploitation of elasmobranchs: Inferences from elasticity, perturbation and phylogenetic analyses. J. Northw. Atl. Fish. Sci. 35: 27-45.

Systema Naturae 2000. 2007. Superorder Batoidea. Systema Naturae 2000. Retrieved December 18, 2007.

Rocco, L, I. Liguori, D. Costagliola, et al. 2007. Molecular and karyological aspects of Batoidea (Chondrichthyes, Elasmobranchi) phylogeny. Gene 389(1): 80-86.

Integrated Taxonomic Information System (ITIS). 2007. [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=563992 Batoidea

Taxonomic Serial No.: 563992]. ITIS Report. Retrieved December 18, 2007.

* Froese, R. and D. Pauly. (Eds.). 2005. Order Rajiformes. FishBase'. Retrieved December 18, 2007.

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.

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.

Froese, R. and D. Pauly. (Eds.). 2004. Family Rajidae: Skates. FishBase'. Retrieved December 14, 2007.

Herbst, S. T. 2001. The New Food Lover's Companion: Comprehensive Definitions of Nearly 6,000 Food, Drink, and Culinary Terms. Barron's Cooking Guide. Hauppauge, NY: Barron's Educational Series. ISBN 0764112589.

Marine Conservation Society. 2007. Fish to avoid: Skates and rays. Marine Conservation Society. Retrieved December 14, 2007.

Murch, A. 2007. Shark taxonomy. Elasmodiver. Retrieved December 14, 2007.

Nelson, J. S. 1994. Fishes of the World. New York: John Wiley and Sons. ISBN 0471547131.

Schmid, R. E. 2007. Shark deaths upset rest of food chain: Shark overfishing may be endangering scallop populations, say scientists. Associated Press/ABCNews May 29, 2007. Retrieved December 14, 2007.

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@@ Line 26: / Line 26: @@
 }}
-'''Rajiformes''' is the order of '''true rays''' and [[skate]]s, flat-bodied [[Chondrichthyes|cartilaginous fishes]] related to [[shark]]s.
+In [[zoology]], '''ray''' is the common name for [[Chondrichthyes|cartilaginous fish]] comprising the order '''Rajiformes''' (or [[Batoidea]]), characterized by enlarged and flat pectoral fins continuous with the head, no anal fin, eyes on the dorsal surface, and a narrow tail. The [[skate]]s comprise a family, Rajidae, within the Rajiformes, and thus can be considered a type of ray. For those taxonomic systems recognizing Batoidea as a superorder, ray may also be used as a term for members of this superorder.
+==Overview==
+The ''[[Chondrichthyes]]'' or "cartilaginous fishes" are jawed [[fish]] with paired fins, paired nostrils, scales, two-chambered [[heart]]s, and skeletons made of [[cartilage]] rather than [[bone]]. They are divided into two subclasses: [[Elasmobranchii]] (sharks, rays, and skates) and Holocephali ([[chimaera]], sometimes called ghost sharks).
-note: In [[zoology]], '''skate''' is the common name for [[Chondrichthyes|cartilaginous fish]] belonging to the family '''Rajidae''' in the superorder [[Batoidea]] of rays, characterized by enlarged and flat pectoral fins continuous with the head, no anal fin, two dorsal fins, and a very slender, spineless tail.
+The Elasmobranchii are sometimes divided into two superorders, Selachimorpha (sharks) and Batoidea or Batidoidimorpha (rays, skates, sawfish). Nelson (1994) notes that there is growing acceptance of the view that sharks and rays together form a monophyletic group (superorder Euselachii), and sharks without rays are a paraphyletic group.
-==Overview==
+There are diverse taxonomies, and Batoidea is variously considered a superorder (eg., Taxonomicon 2007; Frisk et al. 2005; Systema Naturae 2000 2007; Rocco et al. 2007) or an order (ITIS 2007; Froese and Pauly 2005). As a superorder, Batoidea typically includes three orders: Rajiformes (true rays), Torpediniformes (electric rays), and Pristiformes (sawfishes). Some recognize additional orders such as [[Myliobatiformes]] ([[eagle ray]]s) and Rhinobatiformes ([[guitarfish]]es).
-The ''[[Chondrichthyes]]'' or "cartilaginous fishes" are jawed [[fish]] with paired fins, paired nostrils, scales, two-chambered [[heart]]s, and skeletons made of [[cartilage]] rather than [[bone]]. They are divided into two subclasses: [[Elasmobranchii]] (sharks, rays, and skates) and Holocephali ([[chimaera]], sometimes called ghost sharks). The Elasmobranchii are sometimes divided into two superorders, Selachimorpha (sharks) and Batoidea or Batidoidimorpha (rays, skates, sawfish). Nelson (1994) notes that there is growing acceptance of the view that sharks and rays together form a monophyletic group (superorder Euselachii), and sharks without rays are a paraphyletic group.
-Rays, including skates, are placed in the order Rajiformes of the superorder Batoidea (or superorder Euselachii with the sharks). Members of Batoidea are characterized by ventral gill openings, and the anterior edge of the pectoral fin, which is greatly enlarged, is attached to the side of the head anterior to the gill openings (Nelson 1994). Members of Rajiformes also lack an anal fin and the eyes and spiracles are on the dorsal surface (Nelson 1994). The body is normally strongly depressed and in most water for breathing is taken in through the spiracle rather than the mouth.
+==Description==
-==Batoidea==
+True rays, including skates, are placed in the order Rajiformes. Members of Rajiformes are characterized by the anterior edge of the pectoral fin, which is greatly enlarged, being attached to the side of the head anterior to the gill openings (Nelson 1994). They also have ventral gill openings, and the eyes and spiracles are on the dorsal surface (Nelson 1994). The body is normally strongly depressed and in most water for breathing is taken in through the spiracle rather than the mouth. In addition, members of Rajiformes lack an anal fin and lack a nictitating membrane with the cornea attached directly to the skin around the eyes (Nelson 1994).
-{{Taxobox
+Most rays give birth to live young, but the skates in family Rajidae are characterized by eggs that are encased in a horny capsule with four long tips (Nelson 1994).
-| color = pink
-| 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. —>
-Batoids are flat-bodied, and, like sharks, are a species of [[cartilage|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.
+==References==
-The eyes and [[spiracle]]s are located on top of the head.
+* Taxonomicon. 2007. [http://www.taxonomy.nl/Taxonomicon/TaxonTree.aspx?id=42011 Superorder Batoidea]. ''Taxonomicon''. Retrieved December 18, 2007.
-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 ([[Ovoviviparity|ovoviviparous]]). 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]].
+* Frisk, M. G., T. J. Miller, and N. K. Dulvy. 2005. [http://journal.nafo.int/35/frisk/4-frisk.html Life histories and vulnerability to exploitation of elasmobranchs: Inferences from elasticity, perturbation and phylogenetic analyses]. ''J. Northw. Atl. Fish. Sci.'' 35: 27-45.
-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.
+* Systema Naturae 2000. 2007. [http://www.taxonomy.nl/Main/Classification/42011.htm Superorder Batoidea]. ''Systema Naturae 2000''. Retrieved December 18, 2007.
-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]].
+* Rocco, L, I. Liguori, D. Costagliola, et al. 2007. [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T39-4M22067-6&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=0cdf2112451e761678ffbfeb28dfe269  Molecular and karyological aspects of Batoidea (Chondrichthyes, Elasmobranchi) phylogeny]. ''Gene''  389(1): 80-86.
-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).
+* Integrated Taxonomic Information System (ITIS). 2007. [http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=563992 Batoidea
+Taxonomic Serial No.: 563992]. ''ITIS Report''. Retrieved December 18, 2007.
-===Order Rajiformes (true rays)===
-[[Image:Ray.jpg|300px|thumb|right|Ray]]
-* Family [[Anacanthobatidae]] ([[smooth skate]]s)
-* Family [[Dasyatidae]] ([[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)
-===Order Pristiformes (sawfishes) ===
+* * Froese, R. and D. Pauly. (Eds.). 2005. [http://www.fishbase.org/Summary/OrdersSummary.cfm?order=Rajiformes Order Rajiformes]. ''FishBase'. Retrieved December 18, 2007.
-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]]
-==Classification==
-There are several proposed classifications of fish in the superorder [[Batoidea]]. In some classifications the order Rajiformes is split into two or three orders, the additional orders being [[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 [[guitarfish]]es).
-* [[Anacanthobatidae]] ([[smooth skate]]s)
-* [[Dasyatidae]] ([[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.
-* [[Gymnuridae]] ([[butterfly ray]]s)
-* [[Hexatrygonidae]] ([[sixgill stingray]]s)
-* [[Myliobatidae]] ([[eagle ray]]s). The largest of rays, including the giant [[manta ray]]s. Most eagle rays have one poison-carrying spine.
-* [[Plesiobatidae]] ([[deepwater stingray]]s)
-* [[Potamotrygonidae]] ([[river stingray]]s)
-* [[Rajidae]] ([[skate]]s)
-* [[Rhinobatidae]] ([[guitarfish]]es). They have a body structure similar that of the [[sawfish (fish)|sawfishes]], but are not thought to be closely related.
-* [[Urolophidae]] ([[round ray]]s)
-==References==
-{{commonscat|Rajiformes}}
-* {{FishBase order | order = Rajiformes | month = January | year = 2006}}
 * [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.