Editing Osteichthyes (section)

==Comparison with cartilaginous fishes==

{| class="wikitable collapsible expanded"
|-
! width=360px colspan=3 | 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>

|-
! width=110px | Characteristic
! width=250px | Sharks (cartilaginous)
! width=250px | 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
|}