Actinopterygii
Quick Summary
Actinopterygii, commonly known as ray-finned fishes, represent the largest class of fishes, existing for approximately 400 million years. This diverse group encompasses the vast majority of known living and fossil fish species, with around 26,900 living species. Their defining characteristic is their fins, which are supported by bony or horny rays.12
The evolutionary history of Actinopterygii is marked by successive replacement of older groups by newer, better-adapted ones. This lineage includes ancient groups like the Chondrostei, from which modern sturgeons and paddlefishes evolved, and the Holosteans, represented today by gars and bowfins. The most successful and diverse group within Actinopterygii are the teleosts, which include familiar fish like trout, salmon, and tuna. Many teleosts, particularly those in the superorder Acanthopterygii, are characterized by spiny fin rays.134
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vertebrateAnnotated classificationSubclass Actinopterygii (ray-finned fishes) Generally lack choanae; no fleshy base to paired fins; no internal nares; air sacs usually function as swim bladder; skeleton usually well ossified. Subclass Sarcopterygii (lobe-finned fishes) Usually possess a choana; paired fins with a fleshy base over a bony
Read MoreSubclass Actinopterygii (ray-finned fishes) Generally lack choanae; no fleshy base to paired fins; no internal nares; air sacs usually function as swim bladder; skeleton usually well ossified. Subclass Sarcopterygii (lobe-finned fishes) Usually possess a choana; paired fins with a fleshy base over a bony
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fishAnnotated classificationActinopterygii (ray-finned fishes) Fins supported by rays of dermal bone rather than by cartilage. A group of jawed fishes so diverse that no single definition for them can be derived; better understood by determining the distinctive characters of the primitive members and then tracing their…
Read MoreActinopterygii (ray-finned fishes) Fins supported by rays of dermal bone rather than by cartilage. A group of jawed fishes so diverse that no single definition for them can be derived; better understood by determining the distinctive characters of the primitive members and then tracing their…
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- fishActinopterygii: ray-finned fishes
The Actinopterygii, or ray-finned fishes, are the largest class of fishes. In existence for about 400 million years, since the Early Devonian, it consists of some 42 orders containing more than 480 families, at least 80 of which are known only from fossils. The class contains…
Read MoreThe Actinopterygii, or ray-finned fishes, are the largest class of fishes. In existence for about 400 million years, since the Early Devonian, it consists of some 42 orders containing more than 480 families, at least 80 of which are known only from fossils. The class contains…
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chondrosteanEvolution…the most primitive of the ray-finned fishes. They were most numerous and possessed the greatest diversity during the last part of the Paleozoic Era and the beginning of the Mesozoic Era (some 252 million years ago). The earliest chondrosteans were those of the order Palaeonisciformes, a label derived from a…
Read More…the most primitive of the ray-finned fishes. They were most numerous and possessed the greatest diversity during the last part of the Paleozoic Era and the beginning of the Mesozoic Era (some 252 million years ago). The earliest chondrosteans were those of the order Palaeonisciformes, a label derived from a…
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Triassic PeriodFishes and marine reptilesActinopterygians (ray-finned fishes), however, continued to flourish during the Triassic, gradually moving from freshwater to marine environments, which were already inhabited by subholostean ray-finned fishes (genera intermediate between palaeoniscoids and holosteans). The shellfish-eating hybodont sharks, already diversified by the end of the Permian, continued into…
Read MoreActinopterygians (ray-finned fishes), however, continued to flourish during the Triassic, gradually moving from freshwater to marine environments, which were already inhabited by subholostean ray-finned fishes (genera intermediate between palaeoniscoids and holosteans). The shellfish-eating hybodont sharks, already diversified by the end of the Permian, continued into…
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- chondrostean
…major subdivisions of the superclass Actinopterygii, the other two being the holosteans and the teleosts. The only living representatives are the sturgeons (family Acipenseridae) and paddlefishes (family Polyodontidae) in the order Acipenseriformes. Some taxonomies also include the
Read More…major subdivisions of the superclass Actinopterygii, the other two being the holosteans and the teleosts. The only living representatives are the sturgeons (family Acipenseridae) and paddlefishes (family Polyodontidae) in the order Acipenseriformes. Some taxonomies also include the
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teleost…major subdivisions of the class Actinopterygii, the most advanced of the bony fishes. The teleosts include virtually all the world’s important sport and commercial fishes, as well as a much larger number of lesser-known species. Teleosts are distinguished primarily by the presence of a homocercal tail, a tail in which…
Read More…major subdivisions of the class Actinopterygii, the most advanced of the bony fishes. The teleosts include virtually all the world’s important sport and commercial fishes, as well as a much larger number of lesser-known species. Teleosts are distinguished primarily by the presence of a homocercal tail, a tail in which…
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