Many characters show this is a monophyletic group, which includes several groups of fishes, and the tetrapods. Special features include bone and lungs.
Actinistia - dominant predators in Devonian. Autostylic jaw suspension, lobed fins with internal skeleton linked to pectoral and pelvic girdle analogous to amphibia. The coelacanth, Latimeria chalumnae, is extant.
Dipneusti (Dipnoi) - Six species of lungfishes, sister group to the tetrapods.
First appeared in the Devonian, became the dominant fishes in freshwater and began increasing in the oceans from the Mississippi to Carboniferous periods, 340 million years BP.
Bichirs, e.g. Polypterus.
The least derived but most speciose group is the order Palaeonisciformes, from which the neopterygians probably arose. Their greatest abundance was in the Mississippi and Pennsylvanian periods of the Carboniferous. Living forms are in the families Acipenseridae and Polyodontidae.
These fish increasingly dominated in the Triassic, Jurassic and Cretaceous periods, out-competing the chondrosteans. A "new fin" design for increased flexibility, greater mechanical advantage to the cheek muscles, greater expansion of the orobranchial chamber.
Very specialized primitive fish.
Maxilla free from infra-orbitals - free to close side of mouth for inertial suction feeding. Maxilla remains attached to premaxilla anteriorly. Interopercle provides a new pathway of muscle, bones and ligaments to open the mouth.
Teleostei is the largest groups of vertebrates. There is some debate as to whether the group is monophyletic. Great variety of body forms. Generally small fish, less than 30 cm in length.
There are four major teleostean lineages, with debatable relationships within and between them: Osteoglossomorpha - bony tongues (e.g. Arawana), Elopomorpha, Clupeomorpha (including Clupeidae), and Euteleostei - the main line of teleostean evolution with about 17 - 20,000 species, 25 orders and 375 families.
"True teleosts" divided into a number of separate lineages:
a) Protacanthopterygii, Esocids, monophyletic Salmoniformes, smelts (Osmeridae). Other groups, Stomatiformes, Alepocephaloidae, Myctophidae, and Neoscopelidae, may be neoteleosteans.
b) Ostariophysi. Freshwater minnows, catfishes and characins. Includes the toothless Cyprinidae (1/3 of Michigan fishes), Siluridae, Catostomidae,
c) Superorder Stenopterygii (order Stomiformes) and Scopelomorpha. Many "bizarre" deep-sea fish.
d) Neoteleostei, with Paracanthopterygi including cods (Gadiformes) and anglerfishes (Lophiformes) and the Acanthopterygii (spiny-rayed fishes).
Decrease in scale mass and more powerful swimming, especially in acceleration. Tail/fin shapes homocercal in exterior form. Fin-rays allow control over each ray. Spines derived from fin-rays, are also anti-predator devices. Pectoral and pelvic fins shift position in advanced teleosts, concomitant with ubiquity of spines. Swim-bladder - primary hydrostatic function in altitude regulation.
Branchiostegal rays provide a flexible, muscular boundary to the gill cover. Suction pressure is more powerful.
Evolution of jaw flexibility and variation in feeding mechanisms. Premaxilla greatly increased in size and swings to close side of mouth and in most derived teleosts is the basis of jaw protrusability.