Answer to Question #281361 in Zoology for Applied Biology

Question

explain the advances of subclass actinopterygii

Answer 1

-subclass actinopterygii characteristics: -----Ray-finned fishes.

-throughout oceans, but 40% occurs in freshwater .

-about 27,000 species.

-most have bone skeleton w. calcium phosphate Matrix.

-skin usually with thin, flat Bony scales.

-Fins supported by long, semi flexible rays.

-mucus covering reduces drag, prevents infection.

-respire with 4-5 pairs of gills in chamber. -

-homocercal tail.

-well developed skull with 60 bones.

The actinopterygii,or ray finned fishes,are the largest class of fishes. the most primitive of the ray finned fishes. they were most numerous and possessed the greatest diversity during the last part of the paleozoic era and the beginning of the mesozoic Era.

the fins are supported by rays. the swim bladder is also a unique feature of most ray-finned fishes ,enabling them to maintain buoyancy as they move up or down in the water.