What Is The Difference Between Actinopterygii And Sarcopterygii: A Comparative Analysis

Sarcopterygii and Actinistia are two distinct groups within the category of bony fishes. Sarcopterygii, also known as lobe-finned fish, and Actinistia, which are commonly referred to as coelacanths, belong to this diverse class. Among these, Actinopterygii, characterized by their ray-finned fins, further encompasses a subgroup called Teleostei, which is derived from the Greek term signifying “complete bone.” Remarkably, teleosts constitute a significant majority, making up about 95% of the existing fish species. This percentage, in turn, accounts for nearly half of all currently known vertebrate species.

What sets apart class Chondrichthyes from class Actinopterygii is their fundamental anatomical and evolutionary distinctions. Class Chondrichthyes is comprised of jawed fish characterized by their cartilaginous skeletons, and it encompasses approximately 950 species, including well-known representatives like sharks and rays, as well as the less familiar chimaeras or ratfish. On the other hand, class Actinopterygii encompasses an astonishing array of over 20,000 species of bony fish with ray-finned fins. This sheer diversity makes Actinopterygii one of the largest classes in the animal kingdom. These differences in skeletal composition and species diversity shed light on the fundamental variations between these two classes of fish, a topic worth exploring further for a comprehensive understanding of the fish world.