Actinopterygii (subclass)
- Scope note
- Class of vertebrate fish characterized by lepidotrichia or fin rays, meaning their fins are webs of skin supported by bony or horny spines in contrast to the fleshy lobed fins of some other fish. There is generally no fleshy base to their paired fins, no internal nares, their air sacs usually function as swim bladders, and their skeleton is usually well ossified. The class contains 46 orders representing over 30,000 species. The earliest known fossil dates to the Late Silurian, 420 million years ago. In some classifications, it is listed as a class instead of a subclass.
- Date of creation: 02-Dec-2024
Accepted term: 02-Dec-2024 
