Actinopterygii
Actinopterygii
Actinopterygii (/ækˌtɪnɒptəˈrɪdʒiaɪ/), also known as the ray-finned fishes, is a class of the phylum Chordata that includes the majority of fish species.
Etymology
The term "Actinopterygii" is derived from the Greek words "aktis" meaning ray, and "pteryx" meaning fin. This refers to the characteristic bony or spiny rays that support the fins of these fish.
Characteristics
Actinopterygii are characterized by the presence of lepidotrichia, or fin rays, in their fins. These rays are bony or cartilaginous structures that support the fins. This is a distinguishing feature of Actinopterygii, and it is not found in other groups of fish such as the Sarcopterygii or lobe-finned fish.
Other characteristics of Actinopterygii include a swim bladder, which helps the fish maintain buoyancy, and gills for respiration. The gills are covered by a bony plate called the operculum.
Classification
Actinopterygii is the largest class of fish, and it includes over 30,000 species. This class is further divided into several orders, including Perciformes, Cypriniformes, and Siluriformes, among others.
Related Terms
- Chordata: The phylum to which Actinopterygii belong.
- Lepidotrichia: The bony or cartilaginous structures that support the fins of Actinopterygii.
- Sarcopterygii: A class of fish that is distinguished from Actinopterygii by the presence of fleshy, lobed fins.
- Perciformes: An order of Actinopterygii that includes perch and similar fish.
- Cypriniformes: An order of Actinopterygii that includes carp and similar fish.
- Siluriformes: An order of Actinopterygii that includes catfish.
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