Instead, each section introduces important ichthyological concepts and terminology, as well as numerous examples from a diverse range of ray-finned fish families. ( Grande, 1998 Helfman, et al., 1997 Moyle and Cech, 2004)Ĭlearly, given the enormous diversity of this class, entire books could be (and are) written for each of the categories below, so this account does not attempt an exhaustive summary of the diversity of habitats, body forms, behaviors, reproductive habits, etc. Unfortunately, habitat destruction, pollution and international trade, among other human impacts, have contributed to the endangerment of many actinopterygians (see Conservation Status). The latter estimates, however, will probably never be accurate because actinopterygian species are becoming extinct faster than they can be discovered in some areas, such as the Amazon and Congo Basins. Teleosts comprise approximately 23,000 of the 24,000 species within the actinopterygians, and 96 percent of all living fish species (see Systematic/Taxonomic History). At present, approximately 42 orders, 431 families, and nearly 24,000 species are recognized within this class but there are bound to be taxonomic revisions as research progresses. While actinopterygians appeared in the fossil record during the Devonian period, between 400-350 million years ago (Ma), it was not until the Carboniferous period (360 Ma) that they had become dominant in freshwaters and started to invade the seas. ![]() ![]() ![]() Actinopterygians, or ‘ray-finned fishes,’ are the largest and most successful group of fishes and make up half of all living vertebrates.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |