Teleostomi

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Teleostomi

Teleostomi is a clade of Gnathostomata that includes the tetrapods, osteichthyes, and the wholly extinct Acanthodii fish. Key characters of this group include an operculum and a single pair of respiratory openings, features which were lost or modified in some later representatives....
is a clade

Clade

A clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.The term "monophyletic group" is used in this article in the conventional sense of "an a...
of jawed vertebrates

Gnathostomata

Gnathostomata is the group of vertebrates with jaws.The group is traditionally a superclass , broken into two top level groupings; cartilaginous fish, and all other members, including the familiar classes of bony fish, birds, mammals, reptiles, and amphibians....
that includes the tetrapod

Tetrapod

Tetrapods are vertebrate animals having four feet, legs or leglike appendages. Amphibians, reptiles, dinosaurs/birds, and mammals are all tetrapods, and even the limbless snakes are tetrapods by descent....
s, bony fish

Osteichthyes

Osteichthyes , also called bony fish, are a taxonomy group of fish that includes the ray-finned fish and lobe finned fish . The split between these two classes occurred around 440 mya ....
, and the wholly extinct acanthodian

Acanthodii

Acanthodii is a class of extinct fishes, having features of both bony fish and cartilaginous fish . In form they resembled sharks, but their Epidermis was covered with tiny rhomboid platelets like the scales of holosteans ....
fish. Key characters of this group include an operculum

Operculum (fish)

The operculum of a Osteichthyes is the hard bony flap covering and protecting the gills. In most fish, the rear edge of the operculum roughly marks the division between the head and the body....
and a single pair of respiratory openings, features which were lost or modified in some later representatives. The teleostomes include all jawed vertebrates except the chondrichthyans

Chondrichthyes

Chondrichthyes or cartilaginous fishes are jawed fish with paired Fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone....
and the placodermi

Placodermi

The Placodermi were a Class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period....
.

The clade Teleostomi should not be confused with the similar-sounding fish clade Teleostei

Teleostei

Teleostei is one of three infraclasses in class Actinopterygii, the ray-finned fishes. This diverse group, which arose in the Triassic period, includes 20,000 extant species in about 40 orders; most living fishes are members of this group....
.
phylum Vertebrata +-(unranked) Gnathostomatomorpha +-Infraphylum Gnathostomata

Gnathostomata

Placodermi

The Placodermi were a Class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period....
- extinct (armored gnathostomes) +Microphylum Eugnathostomata (true jawed vertebrates) +-Class Chondrichthyes

Chondrichthyes

Chondrichthyes or cartilaginous fishes are jawed fish with paired Fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone....
(cartilaginous fish) +-(unranked) Teleostomi
Teleostomi

Teleostomi is a clade of Gnathostomata that includes the tetrapods, osteichthyes, and the wholly extinct Acanthodii fish. Key characters of this group include an operculum and a single pair of respiratory openings, features which were lost or modified in some later representatives....
(Acanthodii & Osteichthyes) +-Class Acanthodii

Acanthodii

Acanthodii is a class of extinct fishes, having features of both bony fish and cartilaginous fish . In form they resembled sharks, but their Epidermis was covered with tiny rhomboid platelets like the scales of holosteans ....
- extinct ("spiny sharks") +Superclass Osteichthyes

Osteichthyes

Actinopterygii

The Actinopterygii constitute the Class of the ray-finned 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 , as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii....
(ray-finned fish) + +-Class Sarcopterygii

Sarcopterygii

Sarcopterygii - Crossopterygii is traditionally the class of fleshy-finned, lobe-finned fishes, consisting of lungfish, and coelacanths....
(lobe-finned fish) +Superclass Tetrapoda +-Class Amphibia

Amphibian

Amphibians , such as frogs, toads, salamanders, newts and caecilians, are cold-blooded animals that metamorphose from a juvenile, water-breathing form to an adult, air-breathing form....
(amphibia

Amphibian

Amniote

The amniotes are a group of tetrapod vertebrates that have a terrestrially adapted egg. They include the Synapsida and Sauropsida . Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes....
(amniotic egg) +-Class Sauropsida

Reptile

Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded vertebrates that have skin covered in scale as opposed to hair or feathers....
(reptiles or sauropsids) + +-Class Aves

Bird

Birds are wing, Bipedalismal, endothermic , vertebrate animals that lay egg . There are around 10,000 living species, making them the most numerous tetrapod vertebrates....
(birds) +-Class Synapsid

Synapsid

Synapsids , also known as theropsids , are a class of animals that includes mammals and everything closer to mammals than to other living amniotes....
+-Class Mammal

Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
ia (mammals) Note: lines show evolutionary relationships.
origins of the teleostomes are obscure, but their first known fossils are Acanthodians ("spiny sharks") from the Late Ordovician

Ordovician

The Ordovician is a geologic period, the second of six of the Paleozoic era , and covers the time between 488.3?1.7 to 443.7?1.5 million years ago ....
Period.

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Encyclopedia

Teleostomi

Clade

Gnathostomata

Tetrapod

Osteichthyes

Acanthodii

Operculum (fish)

Chondrichthyes

Chondrichthyes or cartilaginous fishes are jawed fish with paired Fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone....
and the placodermi

Placodermi

Teleostei

Taxonomy and phylogeny

Subphylum Vertebrata +-(unranked) Gnathostomatomorpha +-Infraphylum Gnathostomata

Gnathostomata

Placodermi

Chondrichthyes

Acanthodii

Acanthodii is a class of extinct fishes, having features of both bony fish and cartilaginous fish . In form they resembled sharks, but their Epidermis was covered with tiny rhomboid platelets like the scales of holosteans ....
- extinct ("spiny sharks") +Superclass Osteichthyes

Osteichthyes

Actinopterygii

Sarcopterygii

Amphibian

Amniote

Reptile

Reptiles, or members of the class Reptilia, are air-breathing, cold-blooded vertebrates that have skin covered in scale as opposed to hair or feathers....
(reptiles or sauropsids) + +-Class Aves

Bird

Synapsid

Synapsids , also known as theropsids , are a class of animals that includes mammals and everything closer to mammals than to other living amniotes....
+-Class Mammal

Mammal

Origins

The origins of the teleostomes are obscure, but their first known fossils are Acanthodians ("spiny sharks") from the Late Ordovician

Ordovician

The Ordovician is a geologic period, the second of six of the Paleozoic era , and covers the time between 488.3?1.7 to 443.7?1.5 million years ago ....
Period. Living teleostomes constitute the clade Euteleostomi

Euteleostomi

Euteleostomi is a successful clade that includes more than 90% of the living species of vertebrates. Euteleostomes are also known as "bony vertebrates"....
, which includes all osteichthyans and tetrapods. Even after the acanthodians perished at the end of the Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Roderick Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian system" after the ancient kingdom...
, their euteleostome relatives flourished such that today they comprise 99% of living vertebrate species.

Physical characteristics

Teleostomes have two major adaptations that relate to aquatic respiration

Aquatic respiration

Aquatic respiration is the Biological process whereby an aquatic animal obtains oxygen from water.Earth's natural bodies of water have a low oxygen concentration--much lower than the level of oxygen in air at the earth's surface....
. First, the early teleostomes probably had some type of operculum

Operculum (fish)

Fish

A fish is any marine biology vertebrate animal that is typically ectothermic , covered with scale , and equipped with two sets of paired fins and several unpaired fins....
. The development of a single respiratory opening seems to have been an important step. The second adaptation, the teleostomes also developed a gas bladder

Gas bladder

The gas bladder is an internal gas-filled Organ that contributes to the ability of a fish to control its buoyancy, and thus to stay at the current water depth without having to waste energy in swimming....
and the ability to use some atmospheric oxygen

Oxygen

Oxygen no O2 produced; 2) O2 produced, but absorbed in oceans & seabed rock; 3) O2 starts to gas out of the oceans, but is absorbed by land surfaces and formation of ozone layer; 4-5) O2 sinks filled and the gas accumulates]]...
, if primarily for buoyancy

Buoyancy

In physics, buoyancy is the upward force that keeps things afloat. The net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body....
, very early on. The primary function of the bladder is keeping the fish at neutral buoyancy. Later these swim bladders will evolve and modify into lung

Lung

The lung is the essential respiration organ in air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located in the chest on either side of the heart....
s, as in tetrapod

Tetrapod

Otolith

An otolith, , also called statoconium or otoconium is a structure in the saccule or Utricle of the inner ear, specifically in the Labyrinth ....
s, the sagitta in the sacculus, the asteriscus in the lagena, and the lapillus in the utriculus. In dipnoans there are only two otoliths and in Latimeria there is only one.

Teleostomi

Taxonomy and phylogeny

Origins

Physical characteristics

See also