The Bony Fishes Ceolacanths Lobed finned fishes Ceolacanths

The Bony Fishes

Ceolacanths: Lobed finned fishes

Ceolacanths: Lobed finned fishes • Ceolacanths are relics of an evolutionary line that gave rise to the tetrapods, or land vertebrates. • Previously known only from fossils till the first living specimen was discovered in 1938. (Latimeria chalumnae). • Fins are attached by fleshy lobes.

Ceolacanths: Lobed finned fishes

Ray-Finned Fishes • Their fins are attached to the body by fin rays rather than fleshy lobes. • Most numerous and dominant group of vertebrates in the ocean.

Bony Fish Anatomy • Median fins: Dorsal, caudal, and anal fins. Help to maintain a fish’s stability while swimming. • Paired fins: Pectoral and pelvic fins. Used in steering, and stabilization.

Fish Colorization • Counter shading: the fishes back is colored dark, and fades to white on the belly. • When viewed from above the dark blends in with the surrounding water, when viewed from below the white belly blends in with the surface.

Disruptive coloration • Disruptive Coloration: often found in reef fish. Breaks up the pattern. Often times a line will transect the eye. • Makes it more difficult for predators to see or attack the fish.

Cryptic Coloration • Cryptic Coloration: “camouflaging” used to avoid predation.

Poster Colors and Aposematic Coloration • Poster colors: bright showy color patterns that may advertise territorial ownership, aid in foraging individuals to keep in contact, or for sexual displays. • Aposematic coloration: Warning colors advertising to predators that to venomous or spiny to be worth eating.

Locomotion in Bony Fishes

Locomotion in Bony Fishes • The trunk muscles of fishes are arranged as a series of W-shaped bands. • These muscles contract in sequence from anterior to posterior and alternately form one side of the body to the other • By pushing the body against the water, the fish is propelled forward.