neopterygians

Neopterygians are a diverse group of ray-finned fishes (Actinopterygii) that include many modern and extinct lineages. They are characterized by innovations in fin structure, skull morphology, and sensory systems that distinguish them from their earlier counterparts, the acanthopterygians.

The group first appeared during the Late Triassic period and rapidly diversified during the Jurassic and Cretaceous, giving rise to a wide array of aquatic vertebrates. Neopterygians encompass several significant groups, including the teleosts—the most diverse group of fishes today—along with other extinct classes like the Holostei, which includes gars and bowfins.

One of the defining features of neopterygians is the presence of mobile premaxillae and a more flexible jaw structure, which enhanced their feeding capabilities. They also exhibit advanced fin support muscles and a more derived vertebral column, contributing to improved swimming efficiency.

Neopterygians have played a crucial role in aquatic ecosystems and have significant evolutionary importance. Today, they include the majority of commercially important fish species, such as salmon, trout, and cod, particularly within the teleost subgroup.

Research into neopterygians provides insights into vertebrate evolution, especially regarding adaptations related to movement, sensory perception, and ecological specialization. Their fossil record is rich, revealing details about their early origins, adaptive radiations, and extinct forms that help trace the evolutionary history of ray-finned fishes.