Batomorphi

{{Short description|Division of cartilaginous fishes}} {{Automatic taxobox | name = Batomorphs | fossil_range = {{fossilrange|Early Jurassic|Present}}<ref name="conv">{{cite journal | last=Aschliman | first=Neil C. | last2=Nishida | first2=Mutsumi | last3=Miya | first3=Masaki | last4=Inoue | first4=Jun G. | last5=Rosana | first5=Kerri M. | last6=Naylor | first6=Gavin J.P. | title=Body plan convergence in the evolution of skates and rays (Chondrichthyes: Batoidea) | journal=Molecular Phylogenetics and Evolution | url=https://www.sciencedirect.com/science/article/abs/pii/S1055790311005252 | publisher=Elsevier BV | volume=63 | issue=1 | year=2012 | doi=10.1016/j.ympev.2011.12.012 | pages=28–42| url-access=subscription }}</ref> | image = Raya pelágica (Pteroplatytrygon violacea), Cabo de Palos, España, 2022-07-16, DD 69.jpg | image_caption = Pelagic stingray, ''Pteroplatytrygon violacea'' | image_upright = 1.1 | taxon = Batomorphi | authority = Compagno, 1973 | subdivision_ranks = Orders | subdivision = *{{extinct}}Apolithabatiformes * Myliobatiformes * Rajiformes * Rhinopristiformes * Torpediniformes | synonyms = *Batoidimorpha * Batoidea }} [[File:Spotted Eagle Ray (Aetobatus narinari)2.jpg|thumb|upright=1.1|right|{{center|Spotted eagle ray, ''Aetobatus narinari''}}]]

'''Batomorphi''' is a division of cartilaginous fishes, commonly known as '''rays'''; this taxon is sometimes considered as the superorder '''Batoidea''', but the 5th edition of ''Fishes of the World'' classifies it as the division Batomorphi.<ref>{{Cite book |last=Nelson |first=Joseph Schieser |title=Fishes of the world |date=2016 |publisher=John Wiley & Sons |isbn=978-1-119-17484-4 |edition=Fifth |location=Hoboken, New Jersey}}</ref><ref name = Nelson5>{{cite book |author1=Nelson, J.S. |author1-link=Joseph S. Nelson |author2=Grande, T.C. |author3=Wilson, M.V.H. |year=2016 |title=Fishes of the World |edition=5th |publisher=John Wiley & Sons |location=Hoboken, NJ |page=80 |isbn=978-1-118-34233-6 |lccn=2015037522 |oclc=951899884 |ol=25909650M |doi=10.1002/9781119174844}}</ref> Batomorphi, along with the shark division Selachii, both compose the subclass Elasmobranchii. Rays are the most speciose of cartilaginous fishes groups, with well over 600 species in 26 families. Rays are distinguished by their flattened bodies, enlarged pectoral fins that are fused to the head, and gill slits that are placed on their ventral surfaces.

==Description== ===Anatomy=== {{See also|Batomorph locomotion}} Like sharks, Batomorphs are cartilaginous fish (Chondrichthyes), meaning they have a boneless skeleton made of a tough, elastic cartilage. Most batomorphs are dorsoventrally flattened, with a mantle-like body, though the guitarfishes and sawfishes are somewhat less flattened, while most sharks have a spindle-shaped body. Many species of batomorph have developed their pectoral fins into broad flat appendages often referred to as the wings. The anal fin is absent. The eyes and spiracles are located on top of the head. Bottom-dwelling batomorphs breathe by taking water in through the spiracles, rather than through the mouth as most fish do, and passing it outward through the gills, whose openings or gill slits lie under the pectoral fins on the underside, whereas a shark's are on the sides of the head. Most batomorphs have five ventral gill slits, but the Hexatrygonidae have six.<ref>{{cite web |first=R. Aidan |last=Martin |publisher=ReefQuest Centre for Shark Research |url=http://www.elasmo-research.org/education/shark_profiles/batoids.htm |date=February 2010 |website=Elasmo research |title=Batoids: Sawfishes, Guitarfishes, Electric Rays, Skates, and Sting Rays}} </ref>

Batomorphs have a ventrally located mouth and can considerably protrude their upper jaw (palatoquadrate cartilage) away from the cranium to capture prey.<ref>{{cite journal |last1=Motta |first1=P.J. |last2=Wilga |first2=C.D. |year=2001 |title=Advances in the study of feeding behaviors, mechanisms, and mechanics of sharks |journal=Environmental Biology of Fishes |volume=60 |issue=1–3 |pages=131–56 |doi=10.1023/A:1007649900712|s2cid=28305317 }}</ref> The jaws have euhyostylic type suspension, which relies completely on the hyomandibular cartilages for support.<ref>{{cite journal |last=Wilga |first=C.A.D. |year=2008 |title=Evolutionary divergence in the feeding mechanism of fishes |journal=Acta Geologica Polonica |volume=58 |pages=113–20}}</ref> Most batomorphs have developed heavy, rounded teeth for crushing the shells of bottom-dwelling species such as snails, clams, oysters, crustaceans, and some fish, depending on the species. Manta rays feed on plankton using dense gill rakers to capture them. {{anchor|Anchor:Shark/Ray}} {| class="wikitable" |+ Comparison of Elasmobranch fish |- ! Characteristic ! width=235 | Sharks ! width=235 | Guitar fish ! width=235 | Rays |- ! colspan=1 style="background:rgb(255,255,255)" | ! colspan=1 style="background:rgb(255,255,255)" | 300px ! colspan=1 style="background:rgb(255,255,255)" | 200px ! colspan=1 style="background:rgb(255,255,255)" | 180px |- | Shape | laterally compressed spindle | colspan=2; align=center | dorsoventrally compressed (flattened) disc  |- | Habitat | Usually pelagic surface feeders, though carpet sharks are demersal bottom feeders | Often demersal with some pelagic behavior | usually demersal bottom feeders |- | Eyes | Typically at the side of the head, though benthic forms may have dorsally oriented eyes | colspan=2; align=center | Mostly on top of the head |- | Spiracles | not always present | colspan=2; align=center | always present |- | Gill openings | on the sides | colspan=2; align=center | ventral (underneath) |- | Pectoral fins | distinct | colspan=2; align=center | not distinct; blends with the main body  |- | Tail | colspan=2; align=center |Notable caudal fin on muscular tail. | Variable; may have shark-like tail, but many species have finless, whip-like tails, and some have no apparent tail. |- | Locomotion | colspan=2; align=center |Swim by moving their tail (caudal fin) from side to side | Swim by flapping their pectoral fins like wings |}

===Habitat=== Most species live on the sea floor, in a variety of geographical regions – mainly in coastal waters, although some live in deep waters to at least {{convert|3000|m|ft}}. Most batomorphs have a cosmopolitan distribution, preferring tropical and subtropical marine environments, although there are temperate and cold-water species. Only a few species, like manta rays, live in the open sea, and only a few live in freshwater, while some batomorphs can live in brackish bays and estuaries.

===Reproduction=== As is characteristic of elasmobranchs, batomorphs undergo internal fertilization. Internal fertilization is advantageous to batomorphs as it conserves sperm, does not expose eggs to consumption by predators, and ensures that all the energy involved in reproduction is retained and not lost to the environment.<ref name="AtlanCan">{{cite web |url=http://www.marinebiodiversity.ca/skatesandrays/Reproduction%20Overall.htm |title=Reproduction overall |series=Skates and rays of Atlantic Canada |work=Canadian Shark Research Lab |department=Risk Section, Bedford Institute of Oceanography & Marine Fish Species |publisher=Northwest Atlantic Fisheries Center |access-date=27 May 2012 |archive-url=https://web.archive.org/web/20150116083957/http://www.marinebiodiversity.ca/skatesandrays/Reproduction%20Overall.htm |archive-date=2015-01-16 |df=dmy-all }}</ref> All skates and some rays are oviparous (egg laying) while other rays are ovoviviparous, meaning that they give birth to young which develop in a womb but without involvement of a placenta.<ref name="Adams">{{cite journal |last1=Adams |first1=Kye R. |last2=Fetterplace |first2=Lachlan C. |last3=Davis |first3=Andrew R. |last4=Taylor |first4=Matthew D. |last5=Knott |first5=Nathan A. |title=Sharks, rays and abortion: The prevalence of capture-induced parturition in elasmobranchs |journal=Biological Conservation |date=January 2018 |volume=217 |pages=11–27 |doi=10.1016/j.biocon.2017.10.010 |s2cid=90834034 |url=http://marxiv.org/k2qvy/ |access-date=2018-12-09 |archive-date=2019-02-23 |archive-url=https://web.archive.org/web/20190223020619/https://marxiv.org/k2qvy/ }}</ref>

The eggs of oviparous skates are laid in leathery egg cases that are commonly known as mermaid's purses and which often wash up empty on beaches in areas where skates are common.

Capture-induced premature birth and abortion (collectively called capture-induced parturition) occurs frequently in sharks and rays when fished.<ref name="Adams"/> Capture-induced parturition is rarely considered in fisheries management despite being shown to occur in at least 12% of live bearing sharks and rays (88 species to date).<ref name="Adams"/>

==Evolution== Batomorphs belong to the ancient lineage of cartilaginous fishes. Fossil denticles (tooth-like scales in the skin) resembling those of today's chondrichthyans date at least as far back as the Ordovician, with the oldest unambiguous fossils of cartilaginous fish dating from the middle Devonian. A clade within this diverse family, the Neoselachii, emerged by the Triassic, with the best-understood neoselachian fossils dating from the Jurassic. The oldest confirmed ray is ''Antiquaobatis'', from the Pliensbachian of Germany.<ref>{{cite journal |author1=Stumpf, Sebastian |author2=Kriwet, Jürgen |year=2019 |title=A new Pliensbachian elasmobranch (''Vertebrata'', ''Chondrichthyes'') assemblage from Europe, and its contribution to the understanding of late Early Jurassic elasmobranch diversity and distributional patterns |journal=PalZ |volume=93 |issue=4 |pages=637–658 |doi=10.1007/s12542-019-00451-4 |doi-access=free}}</ref> The clade is represented today by sharks, sawfish, rays and skates.<ref>{{cite web |url=http://www.ucmp.berkeley.edu/vertebrates/basalfish/chondrofr.html |department=University of California Museum of Paleontology |publisher=U.C. Berkeley |title=Chondrichthyes: Fossil Record}}</ref>

===Classification=== Molecular evidence refutes the hypothesis that skates and rays are derived sharks.<ref>{{cite journal |last1=Douady |first1=C.J. |last2=Dosay |first2=M. |last3=Shivji |first3=M.S. |last4=Stanhope |first4=M.J. |year=2003 |title=Molecular phylogenetic evidence refuting the hypothesis of Batoidea (rays and skates) as derived sharks |journal=Molecular Phylogenetics and Evolution |volume=26 |pages=215–221 |doi=10.1016/S1055-7903(02)00333-0 |pmid=12565032 |issue=2}}</ref> The monophyly of the skates, the stingrays, and the electric rays has long been generally accepted. Along with Rhinopristiformes, these comprise the four traditionally accepted major batomorph lineages, as in Nelson's 2006 ''Fishes of the World''. However, the exact phylogeny of the major batomorph lineages, internally and with respect to one another, has been subject to diverse treatments. The following cladogram is based on a comprehensive morphological assessment of batomorph phylogeny published in 2004:<ref>{{cite book |first1=J.D. |last1=McEachran |last2=Aschliman |first2=N. |contribution=Phylogeny of batoidea |editor1-last=Carrier |editor1-first=J.C. |editor2-last=Musick |editor2-first=J.A. |editor3-last=Heithaus |editor3-first=M.R. |title=Biology of sharks and their relatives |location=Boca Raton, Florida |publisher=CRC Press |year=2004 |pages=79–114}}</ref>

}} }} }}

However, a 2011 study significantly reevaluated the phylogeny of batomorphs, using nuclear and mitochondrial DNA from 37 taxa, representing almost all recognized families and all of the traditional four major lineages. This is a far more numerous and diverse set of sample taxa than in any previous study, producing findings reflected in the cladogram below.<ref name="conv" />

{{clade|style=font-size:85%;line-height:80% |label1=Chondrichthyes |1={{clade |label2=Elasmobranchii |1=Holocephali (incl. Chimaera) 70px |2={{clade |1=Selachimorpha (Sharks) 100px |label2='''Batoidea''' |2={{clade |1=Rajiformes (Skates) 65px |2={{clade |1={{clade |1=Platyrhinidae (Thornbacks) |2=Torpediniformes (Electric rays) 65px }} |2={{clade |1="Guitarfishes 1" (Trygonorrhinidae) 85px |2={{clade |1="Guitarfishes 2" (incl. Pristidae (Sawfishes)) 110px |2={{clade |1=Zanobatidae (Panrays) |2=Myliobatoidei (Stingrays) 60px }} }} }} }} }} }} }} }}

This study strongly confirmed the traditionally accepted internal monophyly of skates, stingrays, and electric rays. It also recovered panrays as sister to the stingrays, as older morphological analyses had suggested. However, it found the Rhinopristiformes, including the sawfishes and various "guitarfishes", to be paraphyletic, comprising two distinct clades. Referred to as "Guitarfishes 1" and "Guitarfishes 2", the former contains only the Trygonorrhinidae, while the latter contains the remainder of Rhinopristiformes (the families Glaucostegidae, Pristidae, Rhinidae, and Rhinobatidae). In addition, while traditional phylogenies often find electric rays to be the basalmost batomorphs, followed by the Rhinopristiformes, this analysis finds a polytomy between skates, electric rays, and thornbacks at the base of Batomorphi, with weak support for skates being the actual most basal lineage, followed by a clade uniting the electric rays and thornbacks.

The Mesozoic Sclerorhynchoidea were long considered to be basal or ''incertae sedis''; they show features of the Rajiformes but have snouts resembling those of sawfishes. Though considered to be the sister group to sawfishes for a time,<ref>{{cite web |url=http://www.verlag-pfeil.de/07pala/pdf/3_53d03.pdf |title=The systematic position of the Cretaceous sclerorhynchid sawfishes (Elasmobranchii, Pristiorajea) |last=Kriwet |first=Jürgen |access-date=2016-04-04 |archive-date=2016-04-16 |archive-url=https://web.archive.org/web/20160416053715/http://www.verlag-pfeil.de/07pala/pdf/3_53d03.pdf }}</ref> they are now considered true skates (Rajiformes).<ref name="Phylo"/>

The following cladograms are derived from phylogenetic analyses taken from a 2022 study of batomorph morphology by Villalobos-Segura and colleagues;<ref name="Phylo">{{Cite journal|last1=Villalobos-Segura |first1=E. |last2=Marramà |first2=G. |last3=Carnevale |first3=G. |last4=Claeson |first4=K. M. |last5=Underwood |first5=C. J. |last6=Naylor |first6=G. J. P. |last7=Kriwet |first7=J. |title=The Phylogeny of Rays and Skates (Chondrichthyes: Elasmobranchii) Based on Morphological Characters Revisited |year=2022 |journal=Diversity |volume=14 |issue=6 |article-number=456 |doi=10.3390/d14060456 |pmid=35747489 |pmc=7612883 |bibcode=2022Diver..14..456V |doi-access=free }}</ref> {{cladogram|title=Based on parsimony|align=left|cladogram= {{clade |label1=Euselachii |1={{clade |1={{extinct}}Hybodontiformes |label2=Elasmobranchii |2={{clade |1=Selachimorpha |label2='''Batoidea''' |2={{clade |1={{clade |1={{extinct}}''Belemnobatis'' |2={{clade |1={{extinct}}''Spathobatis'' |2={{clade |1={{extinct}}''Asterodermus'' |2={{extinct}}''Kimmerobatis'' }} }} }} |2={{clade |1=Rhinopristiformes |2={{clade |1=Rajiformes |2={{clade |1=Torpediniformes |2=Myliobatiformes }} }} }} }} }} }} }} }} {{cladogram|title=Based on maximum likelihood|align=right|cladogram= {{clade |label1=Euselachii |1={{clade |1={{extinct}}Hybodontiformes |label2=Elasmobranchii |2={{clade |1=Selachimorpha |label2='''Batoidea''' |2={{clade |1={{extinct}}''Spathobatis'' |2={{clade |1={{extinct}}''Belemnobatis'' |2={{clade |1={{extinct}}''Asterodermus'' |2={{extinct}}''Kimmerobatis'' |3={{clade |1=Rajiformes |2={{clade |1=Rhinopristiformes |2={{clade |1=Torpediniformes |2=Myliobatiformes }} }} }} }} }} }} }} }} }} }}

===Subdivisions=== {| class=" wikitable" |- ! rowspan=2 | Order ! rowspan=2 | Image ! rowspan=2 | Common name ! rowspan=2 | Family ! rowspan=2 | Genera ! colspan=4 | Species ! rowspan=2 | Comment |- ! Total ! class=noviewer ! class=noviewer ! class=noviewer |- ! style="background:rgb(110,110,170)" | ''Myliobatiformes'' | 140px | align=center | Stingrays and relatives | align=center | 10 | align=center | 29 | align=center | 223 | align=center | 1 | align=center | 16 | align=center | 33 | {{efn| Myliobatiformes include stingrays, butterfly rays, eagle rays, and manta rays. They were formerly included in the order Rajiformes, but more-recent phylogenetic studies have shown that they are a monophyletic group, and that its more-derived members evolved their highly flattened shapes independently of the skates.<ref name="nelson">{{cite book |title=Fishes of the World |author=Nelson, J.S. |edition=fourth |publisher=John Wiley |year=2006 |isbn=978-0-471-25031-9 |pages=69–82}}</ref>}} |- ! style="background:rgb(130,130,180)" | ''Rajiformes'' | 140px | align=center | Skates and relatives | align=center | 5 | align=center | 36 | align=center | 270 | align=center | 4 | align=center | 12 | align=center | 26 | {{efn| Rajiformes include skates, guitarfishes, and wedgefishes. They are distinguished by the presence of greatly enlarged pectoral fins, which reach as far forward as the sides of the head, with a generally flattened body. The undulatory pectoral fin motion diagnostic to this taxon is known as rajiform locomotion. The eyes and spiracles are located on the upper surface of the body, and the gill slits on the underside. They have flattened, crushing teeth, and are generally carnivorous. Most species give birth to live young, although some lay eggs inside a protective capsule or mermaid's purse.}} |- ! style="background:rgb(110,110,170)" | ''Torpediniformes'' | 140px | align=center | Electric rays | align=center | 4 | align=center | 12 | align=center | 69 | align=center | 2 | align=center | | align=center | 9 | {{efn| The electric rays have electric organs in their pectoral fin discs that generate electric current. They are used to immobilize prey and for defense. The current is strong enough to stun humans, and the ancient Greeks and Romans used these fish to treat ailments such as headaches.<ref name="bullock">{{cite book |last1=Bullock |first1=Theodore Holmes |last2=Hopkins |first2=Carl D. |last3=Popper |first3=Arthur N. |last4=Fay |first4=Richard R. |title=Electroreception |pages=5–7 |publisher=Springer |year=2005 |isbn=978-0-387-23192-1}}</ref>}}<ref name="bullock"/> |- ! style="background:rgb(130,130,180)" | ''Rhinopristiformes'' | 140px | align=center | Shovelnose rays and relatives | align=center | 1 | align=center | 2 | align=center | 5–7 | align=center | 3–5 | align=center | 2 | align=center | | {{efn| The sawfishes are shark-like in form, having tails used for swimming and smaller pectoral fins 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 1.8 metres (6 ft) long, and 30 centimetres (1 ft) wide, and are used for slashing and impaling small fishes and to probe in the mud for embedded animals. Sawfishes can enter freshwater rivers and lakes. Some species reach a total length of 6 metres (20 ft). All species of sawfish are endangered or critically endangered.<ref name=Faria_etal_2013>{{cite journal |last1=Faria |first1=Vicente V. |last2=McDavitt |first2=Matthew T. |last3=Charvet |first3=Patricia |last4=Wiley |first4=Tonya R. |last5=Simpfendorfer |first5=Colin A. |last6=Naylor |first6=Gavin J.P. |year=2013 |title=Species delineation and global population structure of critically endangered sawfishes (Pristidae) |journal=Zoological Journal of the Linnean Society |volume=167 |pages=136–164 |doi=10.1111/j.1096-3642.2012.00872.x |doi-access=free}}</ref>}}<ref name=Faria_etal_2013/> |}

[[File:Heliobatis radians Green River Formation (cropped).jpg|thumb|Early Eocene fossil whipray ''Heliobatis radians'']] [[File:Atlantic mobula lisbon.jpg|thumb|Giant devil ray, ''Mobula mobular'']]

''Eschmeyer's Catalog of Fishes'' classifies the rays as follows:<ref name = ECoF>{{cite web|url=https://www.calacademy.org/scientists/catalog-of-fishes-classification|title=Eschmeyer's Catalog of Fishes Classification|access-date=29 October 2024|publisher=California Academy of Sciences}}</ref>

* Order Torpediniformes **Family Platyrhinidae D. S. Jordan, 1923 (thornbacks or fanrays) **Family Narkidae Fowler, 1934 (sleeper rays) **Family Narcinidae, Gill, 1862 (electric rays) **Family Hypnidae Gill, 1862 (coffin rays) **Family Torpedinidae Henle 1834 (torpedo electric rays or torpedo rays) *Order Rhinopristiformes **Family Trygonorrhinidae Last, Séret & Naylor, 2016 (fiddler rays or banjo rays) **Family Rhinobatidae Bonaparte, 1835 (guitarfishes) **Family Rhinidae J. P. Müller & Henle, 1841 (bowmouth guitarfishes or wedgefishes) **Family Glaucostegidae Last, Séret & Naylor, 2016 (giant guitarfishes) **Family Pristidae Bonaparte, 1835 (sawfishes) *Order Rajiformes **Family Rajidae Blainville, 1816 (hardnose skates) **Family Arhynchobatidae Fowler, 1934 (softnose skates or longtail skates) **Family Gurgesiellidae de Buen, 1959 (pygmy skates) **Family Anacanthobatidae von Bonde & Swart, 1923 (legskates or smooth skates) *Order Myliobatiformes **Family Zanobatidae Fowler. 1934 (panrays) **Family Hexatrygonidae Heemstra & M. M. Smith, 1980 (sixgill stingrays) **Family Dasyatidae D. S. Jordan & Gilbert, 1879 (whiptail stingrays) ***Subfamily Dasyatinae D. S. Jordan & Gilbert, 1879 (stingrays) ***Subfamily Neotrygoninae Castelnau, 1873 (shortsnout stingrays) ***Subfamily Urogymninae Gray, 1851 (whiprays) ***Subfamily Hypolophinae Stromer, 1910 (cowtail stingrays) **Family Potamotrygonidae Garman, 1877 (neotropical stingrays) ***Subfamily Styracurinae Carvalho, Loboda & da Silva 2016 (whiptail stingrays) ***Subfamily Potamotrygoninae Garman 1877 (river stingrays) **Family Urotrygonidae McEachran, Dunn & Miyake, 1996 (American round stingrays) **Family Gymnuridae Fowler, 1934 (butterfly rays) **Family Plesiobatidae K. Nishida, 1990 (deepwater stingrays or giant stingarees) **Family Urolophidae J. P. Müller & Henle 1841 (round stingrays or stingarees) **Family Aetobatidae Agassiz, 1858 (pelagic eagle rays) **Family Myliobatidae Bonaparte, 1835 (eagle rays) **Family Rhinopteridae D. S, Jordan & Evermann, 1896 (cownose rays) **Family Mobulidae Gill, 1893 (mantas or devil rays)

==Conservation== {{see also|List of threatened rays}}

According to a 2021 study in ''Nature'', the number of oceanic sharks and rays has declined globally by 71% over the preceding 50 years, jeopardising "the health of entire ocean ecosystems as well as food security for some of the world's poorest countries". Overfishing has increased the global extinction risk of these species to the point where three-quarters are now threatened with extinction.<ref>{{cite journal |doi = 10.1038/s41586-020-03173-9|title = Half a century of global decline in oceanic sharks and rays|year = 2021|last1 = Pacoureau|first1 = Nathan|last2 = Rigby|first2 = Cassandra L.|last3 = Kyne|first3 = Peter M.|last4 = Sherley|first4 = Richard B.|last5 = Winker|first5 = Henning|last6 = Carlson|first6 = John K.|last7 = Fordham|first7 = Sonja V.|last8 = Barreto|first8 = Rodrigo|last9 = Fernando|first9 = Daniel|last10 = Francis|first10 = Malcolm P.|last11 = Jabado|first11 = Rima W.|last12 = Herman|first12 = Katelyn B.|last13 = Liu|first13 = Kwang-Ming|last14 = Marshall|first14 = Andrea D.|last15 = Pollom|first15 = Riley A.|last16 = Romanov|first16 = Evgeny V.|last17 = Simpfendorfer|first17 = Colin A.|last18 = Yin|first18 = Jamie S.|last19 = Kindsvater|first19 = Holly K.|last20 = Dulvy|first20 = Nicholas K.|journal = Nature|volume = 589|issue = 7843|pages = 567–571|pmid = 33505035| bibcode=2021Natur.589..567P |hdl = 10871/124531|s2cid = 231723355|hdl-access = free}}</ref><ref name="Briggs 2021">{{cite web | last=Briggs | first=Helen | title=Extinction: 'Time is running out' to save sharks and rays | website=BBC News | date=28 January 2021 | url=https://www.bbc.com/news/science-environment-55830732 | access-date=29 January 2021}}</ref><ref name="Richardson 2021">{{cite web | last=Richardson | first=Holly | title=Shark, ray populations have declined by 'alarming' 70 per cent since 1970s, study finds | website=ABC News|publisher=Australian Broadcasting Corporation | date=27 January 2021 | url=https://www.abc.net.au/news/2021-01-28/alarming-70pc-decline-in-shark-and-ray-numbers-study-says/13096442 | access-date=29 January 2021}}</ref> This is notably the case in the Mediterranean Sea - most impacted by unregulated fishing - where a recent international survey of the Mediterranean Science Commission concluded that only 38 species of rays and skates still subsisted.<ref>Guide of Mediterranean Skates and Rays. Oct. 2022. Mendez L., Bacquet A. and F. Briand.[https://ciesm.org/marine/programs/skatesandrays/]</ref>

==See also== {{Commons category|Batomorphi}} *Rhenanida – similarly shaped placoderm fish

==Footnotes== {{notelist|1}}

==References== {{Reflist|25em}}

==Bibliography== * {{cite book |first1=J.D. |last1=McEachran |first2=K.A. |last2=Dunn |first3=T. |last3=Miyake |year=1996 |contribution=Interrelationships of the batoid fishes (Chondrichthyes: Batoidea) |title=Interrelationships of Fishes |publisher=Academic Press}}

==External links== * {{cite web |title=Shark references |url=http://www.shark-references.com/}} – database of bibliography of living/fossil sharks and rays (''see'' Chondrichtyes: Selachii) with more than 15 000 listed papers and many download links. * {{cite report |url=http://www.fish.wa.gov.au/Documents/recreational_fishing/fact_sheets/fact_sheet_rays.pdf |title=Rays fact sheet |series=Recreational fishing |department=Fisheries |publisher=Government of Western Australia |location=Perth, Australia |contribution=Rays Fact Sheet |archive-url=https://web.archive.org/web/20130513144655/http://www.fish.wa.gov.au/Documents/recreational_fishing/fact_sheets/fact_sheet_rays.pdf |archive-date=2013-05-13 |df=dmy-all}}

Category:Batomorphi Category:Extant Early Triassic first appearances Category:Fish superorders