Actinopterygii, also known as ray-finned fishes, are a class of bony fishes that constitute the largest class of vertebrates in existence today. They are characterized by the presence of lepidotrichia, or "fin rays," which are bony spines that support their fins. This group includes over 30,000 species, making it the most diverse class of vertebrates.
Actinopterygii have a long evolutionary history, with fossils dating back to the late Silurian period. They have undergone significant diversification, leading to the wide variety of forms seen today. The group is divided into two subclasses: Chondrostei and Neopterygii.
Actinopterygii are found in a wide range of aquatic environments, from deep oceans to freshwater rivers and lakes. They exhibit a vast array of adaptations that allow them to thrive in different ecological niches.
Actinopterygii play crucial roles in aquatic ecosystems. They are primary consumers, predators, and prey, forming essential links in food webs. Many species are also important to humans for food, recreation, and economic purposes.