Class Osteichthyes (Phylum Chordata)
Examples and Traits
About 28,000 species belong to Class Osteichthyes. The Class is comprised of fish that have bony skeletons as opposed to cartilage. They have paired fins, and flattened bony scales with a mucus covering. They have an operculum, which is a bony flap that is used to cover up the gills. They have a swim bladder, which is a gas/air filled organ used to control the buoyancy of the fish. They have kidneys and a two chambered heart. They reproduce sexually between separate sexes, mostly with external fertilization. There are two different groups of fish in Class Osteichthyes: ray finned fish and lobe finned fish, which are the ancestors of tetrapods.