Teleost n. : One of the Teleosti. Also used adjectively.

Example:
What is the difference between a Teleost (fish) heart and an elasmobranch (shark) heart?

Taxonomy
Teleostei, Superorder Acanthopterygii, teleosts, free encyclopedia, fishes, Protacanthopterygii, early Triassic, ray-finned fishes, modifications, jaw, order Perciformes, London, ITIS, suborder, search, Fossil range, Perca flavescens, Kingdom.

Defination from the web:
Teleost) Jump to: navigation, search. Teleostei. Fossil range: Early Triassic–Recent ... Teleosts have a movable maxilla and premaxilla and corresponding modifications in the jaw musculature. ...