View source for Osteichthyes

{{Short description|Diverse group of vertebrates with skeletons of bone rather than cartilage}}
{{Automatic taxobox
| fossil_range = <br/>[[Ludlow Epoch|Late Silurian]]–[[Holocene|Present]], {{fossil range|earliest=Late Silurian|425.6|0|ref=<ref name="Zhao2021">{{Cite journal |last1=Zhao |first1=W. |last2=Zhang |first2=X. |last3=Jia |first3=G. |last4=Shen |first4=Y. |last5=Zhu |first5=M. |year=2021 |title=The Silurian-Devonian boundary in East Yunnan (South China) and the minimum constraint for the lungfish-tetrapod split |url=https://www.researchgate.net/publication/353479392 |journal=Science China Earth Sciences |volume=64 |issue=10 |pages=1784–1797 |doi=10.1007/s11430-020-9794-8 |bibcode=2021ScChD..64.1784Z |s2cid=236438229}}</ref>}}
| image = Osteichthyes.jpg
| image_caption = Example of Osteichthyes: [[Neoceratodus forsteri|Queensland lungfish]] and [[West Indian Ocean coelacanth]] (two [[Sarcopterygii|sarcopterygians]]), [[iridescent shark]] and  [[Acipenser oxyrinchus|American black sturgeon]] (two [[Actinopterygii|actinopterygians]])
| display_parents = 4
| taxon = Osteichthyes
| authority = [[Thomas Henry Huxley|Huxley]], 1880
| subdivision_ranks = Subgroups
| subdivision = * {{extinct}}''[[Ligulalepis]]''
* {{extinct}}''[[Dialipina]]''
* {{extinct}}''[[Andreolepis]]''
* {{extinct}}''[[Lophosteus]]''
* ?{{extinct}}"Psarolepids"
** ''[[Guiyu oneiros|Guiyu]]''
** ''[[Sparalepis]]''
** ''[[Psarolepis]]''
** ''[[Achoania]]''
* [[Actinopterygii]] <small>(ray-finned fish)</small>
* [[Sarcopterygii]] <small>(lobe-finned fish, including [[tetrapod]]s)</small>
| synonyms = *Euteleostomi
}}

'''Osteichthyes''' ({{IPAc-en|ˌ|ɒ|s|t|iː|ˈ|ɪ|k|θ|iː|z}} {{respell|ost|ee|IK|theez}}; {{etymology|grc|''{{Wikt-lang|grc|ὀστέον}}'' ({{grc-transl|ὀστέον}})|bone||''{{Wikt-lang|grc|ἰχθύς}}'' ({{grc-transl|ἰχθύς}})|fish}}),<ref name="OED">{{cite web |title=Osteichthyes |url=https://www.oed.com/dictionary/osteichthyes_n?tab=factsheet#12270845 |website=oed.com |publisher=Oxford English Dictionary |access-date=15 October 2024}}</ref> also known as '''osteichthyans''' or commonly referred to as the '''bony fish''', is a [[Biodiversity|diverse]] [[clade]] of [[vertebrate]] [[animal]]s that have [[endoskeleton]]s primarily composed of [[bone tissue]]. They can be contrasted with the [[Chondrichthyes]] (cartilaginous fish) and the [[extinct]] [[placoderm]]s and [[acanthodian]]s, which have endoskeletons primarily composed of [[cartilage]]. The vast majority of [[extant taxon|extant]] [[fish]] are members of Osteichthyes, being an extremely diverse and abundant group consisting of 45 [[order (biology)|order]]s, over 435 [[family (biology)|families]] and 28,000 [[species]].<ref>[http://www.seaworld.org/animal-info/info-books/bony-fish/scientific-classification.htm Bony fishes] {{Webarchive|url=https://web.archive.org/web/20130606012932/http://www.seaworld.org/animal-info/info-books/bony-fish/scientific-classification.htm |date=2013-06-06 }} ''[[SeaWorld]]''. Retrieved 2 February 2013.</ref>

The group is divided into two main [[clade]]s, the [[ray-finned fish]] ([[Actinopterygii]], which makes up the vast majority of extant fish) and the [[lobe-finned fish]] ([[Sarcopterygii]], which gave rise to all land vertebrates, i.e. [[tetrapod]]s). The oldest known [[fossil]]s of bony fish are about 425&nbsp;million years old from the late [[Silurian]],<ref name="Zhao2021" /> which are also [[transitional fossil]]s showing a [[dentition|tooth pattern]] that is in between the [[tooth]] rows of [[shark]]s and true bony fishes.<ref>{{cite web| url = http://news.nationalgeographic.com/news/2007/08/070801-jawed-fish.html| archive-url = https://web.archive.org/web/20071114054414/http://news.nationalgeographic.com/news/2007/08/070801-jawed-fish.html| url-status = dead| archive-date = November 14, 2007| title = Jaws, Teeth of Earliest Bony Fish Discovered}}</ref> Despite the name, these early [[basal (phylogenetics)|basal]] bony fish had not yet evolved [[ossification]] and their skeletons were still mostly cartilaginous, and the main distinguishing feature that set them apart from other fish clades were the development of [[lung bud|foregut pouche]]s that eventually evolved into the [[swim bladder]]s and [[lung]]s, respectively.

Osteichthyes is broadly equivalent to '''Euteleostomi'''. In [[paleontology]] the terms are synonymous. In [[ichthyology]] the difference is that Euteleostomi presents a [[cladistic]] view which includes the terrestrial tetrapods that evolved from lobe-finned fish. Until recently, the view of most ichthyologists has been that Osteichthyes were [[paraphyletic]] and include only fishes.<ref name=fotw>{{BioRef|fotw5 |pages=96,101 <!--book-->|title=Teleostomi |gb-page==152<!--eBook preview-->}}</ref> However, since 2013 widely cited ichthyology papers have been published with phylogenetic trees that treat the Osteichthyes as a clade including tetrapods.<ref name=Betancur>{{cite journal|author=Betancur-R, Ricardo |display-authors=etal |year=2013 |title=The Tree of Life and a New Classification of Bony Fishes |journal=PLOS Currents Tree of Life |volume=5 |issue=Edition 1 |doi=10.1371/currents.tol.53ba26640df0ccaee75bb165c8c26288 |pmid=23653398 |pmc=3644299 |doi-access=free }}</ref><ref>Betancur-R, R., Wiley, E.O., Arratia, G., Acero, A., Bailly, N., Miya, M., Lecointre, G. and Orti, G. (2017) "Phylogenetic classification of bony fishes". ''BMC evolutionary biology'', '''17'''(1): 162. {{doi|10.1186/s12862-017-0958-3|doi-access=free}}.</ref><ref>Hughes, L.C., Ortí, G., Huang, Y., Sun, Y., Baldwin, C.C., Thompson, A.W., Arcila, D., Betancur-R, R., Li, C., Becker, L. and Bellora, N. (2018) "Comprehensive phylogeny of ray-finned fishes (Actinopterygii) based on transcriptomic and genomic data". ''Proceedings of the National Academy of Sciences'', '''115'''(24): 6249–6254. {{doi|10.1073/pnas.1719358115}}.</ref><ref name=fotw/>

==Characteristics==
[[File:Guiyu BW.jpg|thumb|left|''[[Guiyu oneiros]]'', the earliest known bony fish, lived during the [[Late Silurian]], 425&nbsp;million years ago.<ref name="Zhao2021"/> It has a combination of both [[Actinopterygii|ray-finned]] and [[Sarcopterygii|lobe-finned]] features.]]

Bony fish are characterized by a relatively stable pattern of [[cranial bone]]s, rooted, medial insertion of [[Mandible|mandibular]] muscle in the lower jaw. The head and [[pectoral girdle]]s are covered with large dermal bones. The eyeball is supported by a [[sclerotic ring]] of four small bones, but this characteristic has been lost or modified in many modern species. The labyrinth in the [[inner ear]] contains large [[otolith]]s. The braincase, or neurocranium, is frequently divided into [[anterior]] and [[posterior (anatomy)|posterior]] sections divided by a [[fissure (anatomy)|fissure]].

Early bony fish had simple [[lung bud|respiratory diverticula]] (an outpouching on either side of the [[esophagus]]) which helped them breathe air in low-oxygen water as a form of supplementary [[enteral respiration]]. In [[ray-finned fish]] these have evolved into [[swim bladder]]s, the changing sizes of which help to alter the body's [[specific density]] and  [[buoyancy]]. In [[elpistostegalia]]ns, a [[crown group]] of [[lobe-finned fish]] that gave rise to the land-dwelling [[tetrapod]]s, these respiratory diverticula became further specialized for obligated air breathing and evolved into the modern [[amphibian]], [[Reptile|reptilian]], [[bird|avian]] and [[mammal]]ian [[lung]]s.<ref name="Clack2012">{{cite book|last=Clack|first=Jennifer A.|author-link=Jenny Clack|title=Gaining Ground, Second Edition: The Origin and Evolution of Tetrapods|url=https://books.google.com/books?id=4j9AKGsQ1msC&pg=PA23|access-date=12 May 2015|date=27 June 2012|publisher=Indiana University Press|isbn=978-0-253-00537-3|pages=23}}</ref><ref name="Laurin2010lungs">{{cite book|last=Laurin|first=Michel|author-link=Michel Laurin|title=How Vertebrates Left the Water|url=https://books.google.com/books?id=fa6gOvRdl9sC&pg=PA38|access-date=14 May 2015|date=2 November 2010|publisher=University of California Press|isbn=978-0-520-94798-6|page=38}}</ref><ref name="Benton2014">{{cite book|last=Benton|first=Michael|author-link=Michael Benton|title=Vertebrate Palaeontology|url=https://books.google.com/books?id=qak-BAAAQBAJ&pg=PT281|access-date=22 May 2015|date=4 August 2014|publisher=Wiley|isbn=978-1-118-40764-6|page=281}}</ref> Early bony fish did not have [[lepidotrichia|fin spine]]s like most modern fish, but instead had the fleshy paddle-like fins similar to other non-bony clades of fish, although the lobe-finned fish evolved [[joint|articulated]] [[appendicular skeleton]]s within their [[paired fins]], which gave rise to tetrapods' [[limb (anatomy)|limb]]s. They also evolved a pair of [[operculum (fish)|opercula]] (gill covers), which can actively draw water across the [[fish gill|gill]]s so they can breathe without having to swim.

Bony fish do not have [[placoid scales]] like cartilaginous fish, but instead have scales that lie underneath the epidermis and do not penetrate it. The three categories of scales in Osteichthyes are cosmoid scales, ganoid scales, and teleost scales. Teleost scales are then divided into two subgroups which are cycloid scales and ctenoid scales. All of these scales have a base of bone that they all originate from; the main difference is that teleost scales have only one layer of bone. Ganoid scales have lamellar bone, and vascular bone that lies on top of the lamellar bone, then enamel that lies on top of both layers of bone. Cosmoid scales have the same two layers of bone that ganoid scales have except that they have dentin in between the enamel and vascular bone.

{{clear}}

==Classification==
{{see also|Evolution of fish|List of prehistoric bony fish genera}}
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Traditionally, Osteichthyes was considered a [[Class (biology)|class]], recognised on the presence of a [[swim bladder]], only three pairs of [[gill arch]]es hidden behind a bony [[operculum (fish)|operculum]], and a predominantly bony skeleton.<ref name="Romer & Parson">{{cite book |last=Parsons |first=Thomas S. |author2=Romer, Alfred Sherwood |author2-link=Alfred Sherwood Romer |title=The vertebrate body|year=1986|publisher=Saunders College Pub.|location=Philadelphia|isbn=978-0-03-910754-3|edition=6th}}</ref> Under this classification system, Osteichthyes was considered [[paraphyletic]] with regard to [[tetrapoda|land vertebrates]], as the common ancestor of all osteichthyans includes [[tetrapod]]s amongst its descendants. While the largest subclass, Actinopterygii (ray-finned fish), is monophyletic, with the inclusion of the smaller subclass Sarcopterygii, Osteichthyes was regarded as paraphyletic.

This has given way to the current [[Cladistics|cladistic]] classification which splits the Osteichthyes into several clades. Under this scheme Osteichthyes is monophyletic, as it includes the tetrapods making it a synonym of the clade [[Euteleostomi]]. Most bony fish belong to the ray-finned fish (Actinopterygii).

In [[ichthyology]] the difference between Euteleostomi and Osteichthyes is that the former presents a [[cladistic]] view, i.e. that the terrestrial [[Tetrapod|tetrapods]] evolved from lobe-finned fish (Sarcopterygii). Until recently, the view of most ichthyologists has been that Osteichthyes were [[paraphyletic]] and include only bony fishes.<ref name="fotw2">{{BioRef|fotw5|pages=96,101 <!--book-->|title=Teleostomi|gb-page==152<!--eBook preview-->}}</ref> However, since 2013 widely cited ichthyology papers have been published with [[phylogenetic trees]] that treat the Osteichthyes as a clade including tetrapods, making the terms Euteleostomi and Osteichthyes synonymous.<ref name="fotw2" /><ref name="Betancur2">{{cite journal |author=Betancur-R, Ricardo |display-authors=etal |year=2013 |title=The Tree of Life and a New Classification of Bony Fishes |journal=PLOS Currents Tree of Life |volume=5 |issue=Edition 1 |doi=10.1371/currents.tol.53ba26640df0ccaee75bb165c8c26288 |pmc=3644299 |pmid=23653398 |doi-access=free}}</ref><ref>Betancur-R, R., Wiley, E.O., Arratia, G., Acero, A., Bailly, N., Miya, M., Lecointre, G. and Orti, G. (2017) "Phylogenetic classification of bony fishes". ''BMC evolutionary biology'', '''17'''(1): 162. {{doi|10.1186/s12862-017-0958-3|doi-access=free}}.</ref><ref>Hughes, L.C., Ortí, G., Huang, Y., Sun, Y., Baldwin, C.C., Thompson, A.W., Arcila, D., Betancur-R, R., Li, C., Becker, L. and Bellora, N. (2018) "Comprehensive phylogeny of ray-finned fishes (Actinopterygii) based on transcriptomic and genomic data". ''Proceedings of the National Academy of Sciences'', '''115'''(24): 6249–6254. {{doi|10.1073/pnas.1719358115}}.</ref>

{{clear}}

{| class="wikitable"
|-
! Clade
! Example
! Description
|-
! [[Actinopterygii]]
| [[File:Carassius carassius.jpg|140px]]{{center|<br />ray-finned fish}}
| valign=top | [[Actinopterygii]], members of which are known as '''ray-finned fishes''', is a [[Class (biology)|class]] of the bony fishes. The ray-finned fishes are so called because they possess [[lepidotrichia]] or "fin rays", their fins being webs of skin supported by bony or horny spines ("rays"), as opposed to the fleshy, lobed fins that characterize the clade [[Sarcopterygii]] which also possess lepidotrichia. These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). In terms of numbers, actinopterygians are the dominant class of [[vertebrate]]s, comprising nearly 99% of the over 30,000 species of fish (Davis, Brian 2010). They are ubiquitous throughout [[freshwater]] and [[ocean|marine]] environments from the deep sea to the highest mountain streams. Extant species can range in size from ''[[Paedocypris]]'', at {{convert|8|mm|in|1|abbr=on}}, to the massive [[giant sunfish]], at {{convert|2700|kg|lb|-2|abbr=on}}, and the long-bodied [[giant oarfish]], at up to {{convert|8|m|ft|0|abbr=on}} (or possibly {{convert|11|m|ft|0|abbr=on}}).
|-
! [[Sarcopterygii]]
| [[File:Coelacanth-bgiu.png|140px]]{{center|<br />lobe-finned fish and tetrapods}}
| [[Sarcopterygii]] ''(fleshy fin)'', members of which are known as '''lobe-finned fish''', is an unranked [[clade]] of the bony fishes. Traditionally, it is a [[class (biology)|class]] or subclass that excludes [[Tetrapoda]], a group of typically terrestrial vertebrates that descends from lobe-finned fish. However, under modern [[cladistic]] classification schemes, Sarcopterygii is a [[clade]] that includes the tetrapods. The living sarcopterygians are the [[coelacanth]]s, [[lungfish]], and tetrapods. Early lobe-finned fishes had fleshy, lobed, paired fins, joined to the body by a single bone.<ref>Clack, J. A. (2002) ''Gaining Ground''. Indiana University</ref> Their fins differ from those of all other fish in that each is borne on a fleshy, lobelike, scaly stalk extending from the body. Pectoral and pelvic fins have articulations resembling those of tetrapod limbs. These fins evolved into legs of the first tetrapod land vertebrates, [[amphibian]]s. They also possess two [[dorsal fin]]s with separate bases, as opposed to the single dorsal fin of [[Actinopterygii|actinopterygian]]s (ray-finned fish). The braincase of sarcoptergygians primitively has a hinge line, but this is lost in tetrapods and lungfish. Many early lobe-finned fishes have a symmetrical tail. All lobe-finned fishes possess teeth covered with true [[tooth enamel|enamel]].
|}

==Phylogeny==
A phylogeny of living Osteichthyes, including the tetrapods, is shown in the [[cladogram]] below.<ref name="Betancur" /><ref>{{cite journal|last1=Betancur-R |year=2013 |title=Complete tree classification (supplemental figure) |journal=PLOS Currents Tree of Life |issue=Edition 1 |url=http://www.deepfin.org/images/Fig_S1_Complete_tree_classification.pdf |display-authors=etal |url-status=dead |archive-url=https://web.archive.org/web/20131021004157/http://www.deepfin.org/images/Fig_S1_Complete_tree_classification.pdf |archive-date=2013-10-21 }}</ref><ref>{{cite journal | last1=Betancur-R| year=2013 | title=Appendix 2 – Revised Classification for Bony Fishes | journal=PLOS Currents Tree of Life | issue= Edition 1 | url=http://currents.plos.org/treeoflife/files/2013/04/Appendix_2_Classification1.pdf |display-authors=etal}}</ref><ref>{{cite journal |title=Phylogenetic classification of bony fishes |author1=Ricardo Betancur-R |author2=Edward O. Wiley |author3=Gloria Arratia |author4=Arturo Acero |author5=Nicolas Bailly |author6= Masaki Miya |author7=Guillaume Lecointre |author8=Guillermo Ortí |journal=BMC Evolutionary Biology |year=2017 |volume=17 |issue=1 |page=162 |doi=10.1186/s12862-017-0958-3 |pmid=28683774 |pmc=5501477 |doi-access=free |bibcode=2017BMCEE..17..162B }}</ref> [[Whole genome duplication|Whole-genome duplication]] took place in the ancestral Osteichthyes.<ref>{{Cite journal|last1=Dehal|first1=Paramvir|last2=Boore|first2=Jeffrey L.|date=2005-09-06|title=Two Rounds of Whole Genome Duplication in the Ancestral Vertebrate|journal=PLOS Biology|language=en|volume=3|issue=10|pages=e314|doi=10.1371/journal.pbio.0030314|pmid=16128622|pmc=1197285|issn=1545-7885 |doi-access=free }}</ref>

{{clade| style=font-size:80%;line-height:80%
|label1='''Osteichthyes'''/
|1={{clade
  |label1=[[Sarcopterygii]] |sublabel1=(lobe-fins)
  |1={{clade
    |label1=[[Actinistia]]
    |1= [[Coelacanthiformes]] [[File:Coelacanth flipped.png|70 px]]
    |label2=[[Rhipidistia]]
    |2={{clade
      |label1=[[Dipnoi]]
      |1=[[Ceratodontiformes]]<span style="{{MirrorH}}">[[File:Chinle fish Arganodus cropped cropped.png|70 px]]</span>
      |label2=[[Tetrapodomorpha]]
      |2=[[Tetrapoda]][[File:Salamandra salamandra (white background).jpg|70 px]]
       }}
     }}
  |label2=[[Actinopterygii]] |sublabel2=(ray-fins)
  |2={{clade
    |label1=[[Cladistia]]
    |1= [[Polypteriformes]][[File:Cuvier-105-Polyptère.jpg|70 px]]
    |label2=[[Actinopteri]]
    |2={{clade
      |label1=[[Chondrostei]]
      |1= [[Acipenseriformes]][[File:Atlantic sturgeon flipped.jpg|70px]]
      |label2=[[Neopterygii]]
      |2={{clade
        |label1=[[Holostei]]
        |1={{clade
          |label1=[[Ginglymodi]]
          |1= [[Lepisosteiformes]][[File:Alligator gar fish (white background).jpg|70px]]
          |label2=[[Halecomorphi]]
          |2= [[Amiiformes]][[File:Amia calva (white background).jpg|70px]]
           }}
        |label2=[[Teleostei]]
        |2={{clade
       
          |label1=[[Elopomorpha]]
          |1={{clade
            |1= [[Elopiformes]][[File:M.E. Blochii ... Systema ichthyologiae iconibus CX illustratum (Plate 82) (white background).jpg|70px]]
            |2={{clade
              |1= [[Albuliformes]][[File:Pterothrissus gissu1.jpg|70px]]
              |2={{clade
                |1= [[Notacanthiformes]][[File:Notacanthus sexspinis1.jpg|70px]]
                |2= [[Anguilliformes]][[File:Anguilla anguilla1.jpg|70px]]
                 }}
               }}
             }}
          |label2=[[Osteoglossocephalai]]
          |2={{clade
           
            |label1=[[Osteoglossomorpha]]
            |1={{clade
               |1=[[Osteoglossiformes]] [[File:F de Castelnau-poissonsPl26 Osteoglossum minus flipped.jpg|70px]]
               |2=[[Hiodontiformes]] [[File:Hiodon tergisus NOAA.jpg|70px]]
               }}
               
            |label2=[[Clupeocephala]]
            |2={{clade
              |label1=[[Otomorpha]]
              |1={{clade
                |label1=[[Otocephala]]
                |1= [[Clupeiformes]][[File:Clupea harengus Gervais.jpg|70px]]
                |label2=
                |2={{clade
                  |label1=[[Alepocephali]]
                  |1= [[Alepocephaliformes]][[File:Xenodermichthys copei1 flipped.jpg|70px]]
                  |label2=[[Ostariophysi]]
                  |2={{clade
                    |label1=[[Anotophysa]]
                    |1= [[Gonorynchiformes]][[File:Chanos chanos Day.png|70px]]
                    |label2=[[Otophysa]]
                    |2={{clade
                      |label1=
                      |1= [[Cypriniformes]][[File:Common carp (white background).jpg|70px]]
                      |2={{clade
                        |1= [[Characiformes]][[File:F de Castelnau-poissonsPl37 (Serrasalmus humeralis).jpg|70px]]
                        |2={{clade
                           |1= [[Gymnotiformes]] [[File:Johann Natterer - Ituí-cavalo (Apteronotus albifrons).jpg|70px]]
                           |2=[[Siluriformes]][[File:Black bullhead flipped.jpeg|70px]]
                           }}
                         }}
                       }}
                     }}
                   }}
                 }}
              |label2=[[Euteleostei|Euteleosteomorpha]]
              |2={{clade
                |label1x=[[Lepidogalaxii]] <!--unnecessary; stretches cladogram horizontally-->
                |1= [[Lepidogalaxiiformes]]
                |2={{clade
                   |1={{clade
                      |label1=[[Protacanthopterygii]]
                      |1={{clade
                         |1= [[Argentiniformes]][[File:Argentina sphyraena.jpg|70px]]
                         |2={{clade
                            |1= [[Galaxiiformes]]<span style="{{MirrorH}}">[[File:Galaxias maculatus.jpg|70px]]</span>
                            |2={{clade
                               |1= [[Salmoniformes]] [[File:Salmo salar flipped.jpg|70px]]
                               |2= [[Esociformes]]<span style="{{MirrorH}}">[[File:Esox lucius1.jpg|70px]]</span>
                               }}
                            }}
                         }}
                      }}
                      |2={{clade
                      |label1=[[Stomiatii]]
                      |1={{clade
                         |1= [[Osmeriformes]][[File:Osmerus mordax flipped.jpg|70px]]
                         |2= [[Stomiatiformes]]<span style="{{MirrorH}}">[[File:Idiacanthus_atlanticus.jpg|70px]]</span>
                         }}
                      |2=[[Neoteleostei]][[File:Zeus faber.jpg|70px]]
                      }}
                    
                   }}
                 }}
               }}
             }}
           }}
         }}
       }}
     }}
   }}
|sublabel1=[[Euteleostomi]]}}

==Biology==
All bony fish possess [[gills]]. For the majority this is their sole or main means of respiration. [[Lungfish]] and other osteichthyan species are capable of respiration through lungs or vascularized swim bladders. Other species can respire through their skin, intestines, and/or stomach.{{sfn|Helfman|Facey|1997}}

Osteichthyes are primitively [[ectothermic]] (cold blooded), meaning that their body temperature is dependent on that of the water. But some of the larger marine osteichthyids, such as the [[opah]],<ref name="Sciencemag">Wegner, Nicholas C., Snodgrass, Owen E., Dewar, Heidi, John, Hyde R. ''[[Science (journal)|Science]]''. [https://www.science.org/doi/10.1126/science.aaa8902 "Whole-body endothermy in a mesopelagic fish, the opah, Lampris guttatus"]. pp. 786–789. Retrieved May 14, 2015.</ref><ref name="SWFSC">[https://swfsc.noaa.gov/news.aspx?ParentMenuId=39&id=20466 "Warm Blood Makes Opah an Agile Predator"]. Fisheries Resources Division of the Southwest Fisheries Science Center of the [[National Oceanic and Atmospheric Administration]]. May 12, 2015. Retrieved May 15, 2015. "New research by NOAA Fisheries has revealed the opah, or moonfish, as the first fully warm-blooded fish that circulates heated blood throughout its body..."</ref> [[swordfish]]<ref name=warmeye1>Fritsches, K.A., Brill, R.W., and Warrant, E.J. 2005. ''[http://www.current-biology.com/content/article/fulltext?uid=PIIS0960982204009960 Warm Eyes Provide Superior Vision in Swordfishes.] {{webarchive|url=https://web.archive.org/web/20060709131003/http://www.current-biology.com/content/article/fulltext?uid=PIIS0960982204009960 |date=2006-07-09 }}'' Current Biology 15: 55−58</ref><ref name=warmeye2>Hopkin, M. (2005). ''[http://www.nature.com/news/2005/050110/full/050110-2.html Swordfish heat their eyes for better vision.]'' Nature, 10 January 2005</ref> and [[tuna]]<ref name=muscletemp>{{cite journal|last1=Sepulveda |first1=C.A. |last2=Dickson |first2=K.A. |last3=Bernal |first3=D. |last4=Graham |first4=J.B. |title=Elevated red myotomal muscle temperatures in the most basal tuna species, ''Allothunnus fallai'' |journal=Journal of Fish Biology |date=1 July 2008 |volume=73 |issue=1 |pages=241–249 |doi=10.1111/j.1095-8649.2008.01931.x |bibcode=2008JFBio..73..241S |url=http://216.172.180.32/~pier/userdocs/images/files/scientific_publications/Sepulveda%20et%20al.%202008%20.pdf |access-date=2 November 2012 |url-status=dead |archive-url=https://web.archive.org/web/20130207000108/http://216.172.180.32/~pier/userdocs/images/files/scientific_publications/Sepulveda%20et%20al.%202008%20.pdf |archive-date=February 7, 2013 }}</ref> have independently evolved various levels of [[endothermy]]. Bony fish can be any type of [[heterotroph]]: numerous species of [[omnivore]], [[carnivore]], [[herbivore]], [[filter-feeder]], [[detritivore]], or [[hematophage]] are documented.

Some bony fish are [[hermaphrodite]]s, and a number of species exhibit [[parthenogenesis]]. Fertilization is usually external, but can be internal. Development is usually [[oviparous]] (egg-laying) but can be [[Ovoviviparity|ovoviviparous]], or [[Viviparity|viviparous]]. Although there is usually no parental care after birth, before birth parents may scatter, hide, guard or brood eggs, with [[sea horses]] being notable in that the males undergo a form of "pregnancy", brooding eggs deposited in a ventral pouch by a female.

==Examples==
[[File:Mola alexandrini 60816634.jpg |thumb |The [[giant sunfish]] is the heaviest bony fish in the world.]]

The [[giant sunfish]] is the heaviest bony fish in the world. In late 2021, Portuguese fishermen found a dead sunfish near the coast of [[Faial Island]], [[Azores]]. At {{convert|2744|kg|lb}} in weight, {{convert|3.6|m|ft}} in height, and {{convert|3.5|m|ft}} in length, it was the biggest [[giant sunfish]] ever captured.<ref name="biggestsunfish">{{cite news |last1=Stan |first1=Joshua |title=Discovered Remains of Sunfish in the Azores Set World Record as Largest Bony Fish |url=https://www.sciencetimes.com/articles/40530/20221017/discovered-remains-sunfish-azores-set-world-record-largest-bony-fish.htm |access-date=23 October 2022 |work=Science Times |publisher=Journal of Fish Biology |date=17 October 2022}}</ref>

The longest is the [[Giant oarfish|king of herrings]], a type of [[oarfish]]. Other very large bony fish include the [[Atlantic blue marlin]], some specimens of which have been recorded as in excess of {{convert |820 |kg |lb}}, the [[black marlin]], some [[sturgeon]] species, and the [[Giant grouper|giant]] and [[Pacific goliath grouper|goliath grouper]], both of which can exceed {{convert|300|kg|lb}} in weight. In contrast, ''[[Paedocypris progenetica]]'' and the [[stout infantfish]] can measure less than {{convert|8|mm|in}}.<ref>{{cite web |last=Busson |first=Frédéric |title=Paedocypris progenetica |url=http://www.fishbase.org/summary/Paedocypris-progenetica.html |publisher=FishBase |access-date=13 January 2012 |author2=Froese, Rainer |date=15 November 2011}}</ref><ref name=fishbase>{{FishBase |genus=Schindleria |species=brevipinguis |year=2017 |month=September}}</ref>
The [[Beluga (sturgeon)|beluga sturgeon]] is the largest species of freshwater bony fish extant today, and ''[[Arapaima gigas]]'' is among the largest of the freshwater fish. The largest bony fish ever was ''[[Leedsichthys]]'', which dwarfed the beluga sturgeon as well as the [[ocean sunfish]], [[giant grouper]] and all the other giant bony fishes alive today.<ref name="Liston2013">{{cite book |author=Liston, J., Newbrey, M., Challands, T., and Adams, C., 2013 |chapter=Growth, age and size of the Jurassic pachycormid ''Leedsichthys problematicus'' (Osteichthyes: Actinopterygii) |editor=Arratia, G., Schultze, H. and Wilson, M. |title=Mesozoic Fishes 5 – Global Diversity and Evolution |date=2013 |publisher=Verlag Dr. Friedrich Pfeil |location=München, Germany |pages=145–175 |isbn=9783899371598 |chapter-url=https://eprints.gla.ac.uk/81797/1/81797.pdf}}</ref>

{{anchor |Anchor:Bony/Cartilaginous}}

==Comparison with cartilaginous fishes==

{| class="wikitable collapsible" style="min-width:50ch"
|+ Comparison of [[Cartilaginous fish|cartilaginous]] and bony fishes <ref>Based on: Kotpal R. L. (2010) [https://books.google.com/books?id=U7N1j-8LMsEC&dq=%22origin+of+fins%22&pg=PA199 ''Modern Text Book Of Zoology Vertebrates''] {{webarchive|url=https://web.archive.org/web/20160422233140/https://books.google.com/books?id=U7N1j-8LMsEC |date=2016-04-22 }} Pages 193. Rastogi Publications. {{ISBN|9788171338917}}.</ref>

|-
! Characteristic
! Sharks (cartilaginous)
! Bony fishes
|-
| [[Habitat]]
| Mainly marine
| Marine and freshwater
|-
| Shape
| Usually [[Anatomical terms of location#Dorsal and ventral|dorso-ventrally]] flattened
| Usually [[Bilateral symmetry|bilaterally]] flattened
|-
| [[Exoskeleton]]
| Separate dermal [[placoid scale]]s
| Overlapping dermal [[cosmoid scale|cosmoid]], [[ganoid scale|ganoid]], [[cycloid scale|cycloid]] or [[ctenoid scale]]s
|-
| [[Endoskeleton]]
| Cartilaginous
| Mostly bony
|-
| [[Caudal fin]]
| [[Heterocercal]]
| Heterocercal or [[diphycercal]]
|-
| [[Pelvic fin]]s
| Usually posterior.
| Mostly anterior, occasionally posterior.
|-
| [[Intromittent organ]]
| Males use [[pelvic fin]]s as [[clasper]]s for transferring sperm to a female
| Do not use claspers, though some species use their [[anal fin]]s as [[gonopodium]] for the same purpose
|-
| [[Mouth]]
| Large, crescent shaped on the ventral side of the head
| Variable shape and size at the tip or terminal part of the head
|-
| [[Fish jaw|Jaw suspension]]
| Hyostylic
| Hyostylic and autostylic
|-
| [[Fish gill|Gill openings]]
| Usually five pairs of [[gill slit]]s which are not protected by an operculum.
| Five pairs of gill slits protected by an [[Operculum (fish)|operculum]] (a lateral flap of skin).
|-
| [[Fish gill|Type of gills]]
| Larnellibranch with long interbranchial [[septum]]
| [[Leaf shape|Filiform]] with reduced interbranchial septum
|-
| [[Spiracle (vertebrates)|Spiracles]]
| The first gill slit usually becomes spiracles opening behind the eyes.
| No spiracles
|-
| [[wiktionary:Afferent|Afferent]] [[Branchial arch|branchial]] vessels
| Five pairs from [[ventral aorta]] to gills
| Only four pairs
|-
| [[wiktionary:Efferent|Efferent]] [[Branchial arch|branchial]] vessels
| Nine pairs
| Four pairs
|-
| [[Conus arteriosus]]
| Present in heart
| Absent
|-
| [[Cloaca]]
| A true cloaca is present only in cartilaginous fishes and [[lobe-finned fish]]es.
| In most bony fishes, the cloaca is absent, and the anus, urinary and genital apertures open separately <ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 396–399|isbn= 978-0-03-910284-5}}</ref>
|-
| [[Stomach]]
| Typically J-shaped
| Shape variable. Absent in some.
|-
| [[Intestine]]
| Short with [[spiral valve]] in [[Lumen (anatomy)|lumen]]
| Long with no spiral valve
|-
| [[Rectal gland]]
| Present
| Absent
|-
| [[Liver]]
| Usually has two [[Liver lobe|lobes]]
| Usually has three lobes
|-
| [[Swim bladder]]
| Absent
| Usually present
|-
| [[Brain]]
| Has large [[Olfactory bulb|olfactory lobe]]s and [[cerebrum]] with small [[Midbrain#Corpora quadrigemina|optic lobes]] and [[cerebellum]]
| Has small olfactory lobes and cerebrum and large optic lobes and cerebellum
|-
| [[Restiform body|Restiform bodies]]
| Present in brain
| Absent
|-
| [[Ductus endolymphaticus]]
| Opens on top of head
| Does not open to exterior
|-
| [[Retina]]
| Lacks [[Cone cell|cones]]
| Most fish have [[Vision in fishes#Double cones|double cones]], a pair of cone cells joined to each other.
|-
| [[Accommodation in fish|Accommodation]] of eye
| Accommodate for near vision by moving the lens closer to the retina
| Accommodate for distance vision by moving the lens further from the retina <ref>{{cite journal | last1 = Schwab | first1 = IR | last2 = Hart | first2 = N | year = 2006 | title = More than black and white | journal = British Journal of Ophthalmology | volume = 90 | issue = 4| page = 406 | doi = 10.1136/bjo.2005.085571 | pmc=1857009 | pmid=16572506}}</ref>
|-
| [[Ampullae of Lorenzini]]
| Present
| Absent
|-
| Male genital duct
| Connects to the anterior part of the genital kidney
| No connection to kidney
|-
| [[Oviduct]]s
| Not connected to ovaries
| Connected to ovaries
|-
| Urinary and genital apertures
| United and [[urinogenital]] apertures lead into common [[cloaca]]
| Separate and open independently to exterior
|-
| [[Egg]]s
| A small number of large eggs with plenty of yolk
| A large number of small eggs with little yolk
|-
| [[Fertilisation]]
| Internal
| Usually external
|-
| Development
| [[Ovoviviparous]] types develop internally. [[Oviparous]] types develop externally using [[Egg case (Chondrichthyes)|egg cases]]
| Normally develop externally without an egg case
|}

==See also==
*[[Ostracoderm]] - armoured jawless fish.
*[[Prehistoric fish]]

{{clear}}

==References==

{{reflist}}

== Sources ==

{{Commons category|Osteichthyes}}
{{Wikispecies|Osteichthyes}}

* {{cite book |last1=Helfman |first1=G.S. | last2=Facey |first2=D.E. |year=1997 |title=The Diversity of Fishes |publisher=Blackwell Sciences |isbn=978-0-86542-256-8 }}

{{Chordata}}
{{Evolution of fish}}
{{Gnathostomata|state=collapsed}}
{{Taxonbar|from=Q27207}}
{{Authority control}}

[[Category:Osteichthyes| ]]
[[Category:Pridoli first appearances]]
[[Category:Extant Silurian first appearances]]
[[Category:Superclasses (biology)]]