OSTEICHTHYES /ˌɒstiːˈɪkθi.iːz/ , popularly referred to as the
BONY FISH, is a diverse taxonomic group of fish that have skeletons
primarily composed of bone tissue , as opposed to cartilage . The vast
majority of fish are members of Osteichthyes, which is an extremely
diverse and abundant group consisting of 45 orders, and over 435
families and 28,000 species. It is the largest class of vertebrates
in existence today. The group
Osteichthyes is divided into the
ray-finned fish (
Actinopterygii ) and lobe-finned fish (Sarcopterygii
). The oldest known fossils of bony fish are about 420 million years
ago, which are also transitional fossils , showing a tooth pattern
that is in between the tooth rows of sharks and bony fishes.
Osteichthyes can be compared 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, whereas on a traditional
Osteichthyes includes only fishes and is therefore paraphyletic
. However, recently published phylogenetic trees treat the
Osteichthyes as a clade.
* 1 Characteristics
* 2 Classification
* 3 Phylogeny
* 4 Biology
* 5 Examples
* 6 Comparison with cartilaginous fishes
* 7 See also
* 8 References
* 8.1 Citations
* 8.2 Bibliography
Guiyu oneiros , the earliest known bony fish, lived during the
Silurian , 419 million years ago). It has the combination of
both ray-finned and lobe-finned features, although analysis of the
totality of its features place it closer to lobe-finned fish.
Bony fish are characterized by a relatively stable pattern of cranial
bones , rooted, medial insertion of mandibular muscle in the lower
jaw. The head and pectoral girdles 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 otoliths
. The braincase, or neurocranium, is frequently divided into anterior
and posterior sections divided by a fissure .
Early bony fish had simple lungs (a pouch on either side of the
esophagus) which helped them breathe in low-oxygen water. In many bony
fish these have evolved into swim bladders , which help the body
create a neutral balance between sinking and floating. (The lungs of
amphibians, reptiles, birds, and mammals were inherited from their
bony fish ancestors.) They do not have fin spines, but instead
support the fin with lepidotrichia (bone fin rays). They also have an
operculum , which helps them breathe without having to swim.
Bony fish have no placoid scales . Mucus glands coat the body. Most
have smooth and overlapping ganoid , cycloid or ctenoid scales.
Osteichthyes is considered a class , recognised on
having a swim bladder , only three pairs of gill arches , hidden
behind a bony operculum and a predominately bony skeleton. Under this
classification systems, the
Osteichthyes are paraphyletic with regard
to land vertebrates as the common ancestor of all Osteichthyes
includes tetrapods amongst its descendants. The largest subclass, the
Actinopterygii (ray-finned fish) are monophyletic, but with the
inclusion of the smaller sub-class Sarcopterygii,
This has led to an alternative classification, splitting the
Osteichthyes into two full classes. Paradoxically,
under this scheme monophyletic, as it includes the tetrapods, making
it a synonym of the clade
Euteleostomi . Most bony fish belong to the
ray-finned fish (Actinopterygii).
Actinopterygii , or RAY-FINNED FISHES, constitute
a class or subclass 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 class
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
vertebrates , comprising nearly 99% of the over 30,000 species of fish
(Davis, Brian 2010). They are ubiquitous throughout freshwater and
marine environments from the deep sea to the highest mountain streams.
Extant species can range in size from
Paedocypris , at 8 mm (0.3 in),
to the massive ocean sunfish , at 2,300 kg (5,070 lb), and the
long-bodied oarfish , to at least 11 m (36 ft).
Sarcopterygii (fleshy fin) or LOBE-FINNED FISH
constitute a clade (traditionally a class or subclass of fish only,
i.e. excluding the tetrapods ) of the bony fish, though a strict
cladistic view includes the terrestrial vertebrates . The living
sarcopterygians are the coelacanths , lungfish , and the tetrapods .
Early lobe-finned fishes had fleshy, lobed, paired fins, joined to the
body by a single bone. 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, amphibians . They also possess two dorsal
fins with separate bases, as opposed to the single dorsal fin of
actinopterygians (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 enamel .
The phylogeny of living bony fishes is shown in the cladogram .
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
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 , swordfish and
tuna have independently evolved various levels of endothermy . Bony
fish can be any type of heterotroph : numerous species of omnivore ,
carnivore , herbivore , filter-feeder or detritivore are documented.
Some bony fish are hermaphrodites , and a number of species exhibit
parthenogenesis . Fertilization is usually external, but can be
internal. Development is usually oviparous (egg-laying) but can be
ovoviviparous, or 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
The ocean sunfish is the heaviest bony fish in the world, while the
longest is the king of herrings , a type of oarfish . Specimens of
ocean sunfish have been observed up to 3.3 metres (11 ft) in length
and weighing up to 2,303 kilograms (5,077 lb). Other very large bony
fish include the
Atlantic blue marlin
Atlantic blue marlin , some specimens of which have
been recorded as in excess of 820 kilograms (1,810 lb), the black
marlin , some sturgeon species, and the giant and goliath grouper ,
which both can exceed 300 kilograms (660 lb) in weight. In contrast,
the dwarf pygmy goby measures a minute 15 millimetres (0.59 in).
Arapaima gigas is the largest species of freshwater bony fish. The
largest bony fish ever was
Leedsichthys , which dwarfed the beluga
sturgeon , ocean sunfish , giant grouper , and all the other giant
bony fishes alive today.
COMPARISON WITH CARTILAGINOUS FISHES
Cartilaginous fishes can be further divided into sharks , rays and
chimaeras . In the table below, the comparison is made between sharks
and bony fishes. For the further differences with rays, see sharks
versus rays .
COMPARISON OF CARTILAGINOUS AND BONY FISHES
Marine and freshwater
Usually dorso-ventrally flattened
Usually bilaterally flattened
Separate dermal placoid scales
Overlapping dermal cosmoid , ganoid , cycloid or ctenoid scales
Heterocercal or diphycercal
Mostly anterior, occasionally posterior.
Males use pelvic fins as claspers for transferring sperm to a
Do not use claspers, though some species use their anal fins as
gonopodium for the same purpose
Large, crescent shaped on the ventral side of the head
Variable shape and size at the tip or terminal part of the head
Hyostylic and autostylic
Usually five pairs of gill slits which are not protected by an
Five pairs of gill slits protected by an operculum (a lateral flap
Type of gills
Larnellibranch with long interbranchial septum
Filiform with reduced interbranchial septum
The first gill slit usually becomes spiracles opening behind the
Afferent branchial vessels
Five pairs from ventral aorta to gills
Only four pairs
Efferent branchial vessels
Present in heart
A true cloaca is present only in cartilaginous fishes and
lobe-finned fishes .
In most bony fishes, the cloaca is absent, and the anus, urinary
and genital apertures open separately
Shape variable. Absent in some.
Short with spiral valve in lumen
Long with no spiral valve
Usually has two lobes
Usually has three lobes
Has large olfactory lobes and cerebrum with small optic lobes and
Has small olfactory lobes and cerebrum and large optic lobes and
Present in brain
Opens on top of head
Does not open to exterior
Most fish have double cones , a pair of cone cells joined to each
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
Ampullae of Lorenzini
Male genital duct
Connects to the anterior part of the genital kidney
No connection to kidney
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
A small number of large eggs with plenty of yolk
A large number of small eggs with little yolk
Ovoviviparous types develop internally.
Oviparous types develop
externally using egg cases
Normally develop externally without an egg case
Wikimedia Commons has media related to OSTEICHTHYES .
Wikispecies has information related to: OSTEICHTHYES
Ostracoderm - armoured jawless fish.
SeaWorld . Retrieved 2 February 2013.
* ^ Jaws, Teeth of Earliest Bony
* ^ Betancur-R, Ricardo; et al. (2013). "The Tree of Life and a New
Classification of Bony Fishes". PLOS Currents Tree of Life (Edition
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* ^ "2009/03/guiyu-oldest-articulated-osteichthyan_26".
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conocimientos clave sobre origen de los
vertebrados_Spanish.china.org.cn". spanish.china.org.cn. Retrieved
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* ^ Betancur-R; et al. (2013). "Appendix 2 – Revised
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* ^ Helfman 1997 .
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* ^ "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..."
* ^ Fritsches, K.A., Brill, R.W., and Warrant, E.J. 2005. Warm Eyes
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* Helfman, G.S.; Facey, D.E (1997). "The Diversity of Fishes".
Extant classes of phylum
* Kingdom Animalia
* Superphylum Deuterostomia
* Leptocardii (lancelets)
Ascidiacea (sea squirts)
* Appendicularia (larvaceans)
Thaliacea (pyrosomes, salps, doliolids)
(Vertebrates + Myxini )
(fish + Tetrapods)
AGNATHA (JAWLESS FISH)
* Myxini (hagfish)
Chondrichthyes (cartilaginous fish: sharks, rays, chimaeras)
Actinopterygii (ray-finned fish)
Actinistia (coelacanths) ¹
* Dipnoi (lungfish) ¹
* Amphibia (amphibians)
* Mammalia (mammals)
(withal Diapsida )
Rhynchocephalia (tuatara) ²
Squamata (scaled reptiles) ²
* Testudines (turtles) ²,³
Crocodilia (crocodilians) ²
* Aves (birds)
* ¹subclasses of
* ²orders of class Reptilia (reptiles)
* ³traditionally placed in Anapsida
* italic are paraphyletic groups
Evolution of fish
* †Protoconodonta ?
Lists of prehistoric fish
* spiny sharks
List of transitional fossils
* Wd : Q27207
* EoL : 2775704
Fossilworks : 218963
* ITIS : 161030