Teleost

Teleosts are the dominant fish of the present day. They arose in the Mesozoic era, and include 20,000 living species. The oldest teleost fossils date back to the late Triassic. They evolved from fish like bowfins in the clade Holostei. During the Mesozoic and Cainozoic they diversified. 96 percent of all known fish species are teleosts.

They are, in order of evolution, vertebrates, jawed fish (Gnathostomata), bony fish (Osteichthyes) and ray-finned fish (Actinopterygii).Nelson, Joseph S. 2006. Fishes of the world. Wiley, N.Y. .Helfman G. Collette B. & Facey D. 1997. The diversity of fishes. Blackwell, Oxford. 

 Advantages 
To account for their success, teleosts must have advantages over earlier fish. In general, teleosts tend to be quicker and more flexible than earlier bony fishes. Their skeletal structure has evolved towards greater lightness. Teleost bones are constructed from a scaffolding of struts, which makes them strong without adding weight.

Teleosts have a movable jaw and changes in the jaw muscles. These changes make it possible for them to protrude their jaws outwards from the mouth. This adaptation improves their ability to grab fast-moving prey.Video of a slingjaw wrasse catching prey by protruding its jawVideo of a red bay snook catching prey by suction feeding

 Date of origin 
The date of origin of the teleosts is a difficult problem. Two kinds of evidence are available. There is evidence from the fossil record that the first teleost comes from the late Triassic period.Kemp T.S. 1999. Fossils and evolution. Oxford University Press. p122 Palmer D. (ed) 1999. The Marshall illustrated encyclopedia of dinosaurs and prehistoric animals. London: Marshall Editions. p38 

This date is somewhat later than molecular divergence time estimates (molecular clock). A recent paper finds that fossil dates and molecular clock dates are similar to each other.Near, Thomas J. et al. 2012. Resolution of ray-finned fish phylogeny and timing of diversification. PNAS (Proceedings of the National Academy of Sciences of the United States of America). pp. 13698–13703.   These researchers state:
"Divergence times estimated from relaxed-molecular clock analyses yield a comprehensive time-scale of actinopterygian diversification that is remarkably close to ages inferred from the fossil record".


 Teleost superorders 
Teleostei
 Osteoglossomorpha (freshwater elephantfish, mooneyes, Arapaima)
 Elopomorpha (eels)
 Clupeomorpha (herrings, anchovies)
 Ostariophysi (carp, goldfish, minnows, catfish, piranha, electric eels)
 Protacanthopterygii (salmon, trout, pike)
 Stenopterygii (marine hatchetfish)
 Cyclosquamata (Bombay duck. lancetfish)
 Scopelomorpha (lanternfish)
Lampridiomorpha (ribbonfish)
 Polymyxiomorpha (beardfish)
 Paracanthopterygii (cavefish, cod, anglerfish)
 Acanthopterygii (mullet, silverside, dory, flyingfish, stickleback, seahorse)
 16 Orders, and especially the Order Perciformes (40% of all fish): bass, cichlid, mackerel, tuna, perch, filefish, pufferfish, flatfish, goby, blenny, whiting, wrasse)

 References