Definition

1. Noun:
   • A taxonomic class of fish: "Class Osteichthyes" is the scientific name for the group of fish that possess a skeleton primarily composed of true bone, as opposed to cartilage. This class includes the vast majority of living fish species.

Usage

• The term "Class Osteichthyes" is used in formal, scientific contexts such as biology, zoology, and ichthyology (the study of fish) to categorize and discuss bony fish.
• It is typically used with a singular verb, as it refers to a single taxonomic group.

Examples

• Noun:
  • Salmon, tuna, and goldfish all belong to the class Osteichthyes.
  • The evolution of the swim bladder is a key characteristic of the class Osteichthyes.

Advanced Usage

• In phylogenetic classification: The class Osteichthyes is sometimes subdivided into two main subclasses: Actinopterygii (ray-finned fish) and Sarcopterygii (lobe-finned fish, which include the ancestors of tetrapods).
  • Modern taxonomy places coelacanths within the subclass Sarcopterygii of the class Osteichthyes.

Variants and Related Words

• Osteichthyan (noun/adjective): A member of the class Osteichthyes; pertaining to bony fish.
  • The osteichthyan lineage is incredibly diverse.
• Bony fish (common noun): The common, non-scientific term for members of the class Osteichthyes.
  • Bony fish are found in almost every aquatic habitat.

Synonyms

• Bony fishes: The direct common-name synonym for members of this class.
• Teleostomi (in some older or alternative classifications): A broader taxonomic group that includes bony fish and their close relatives.

Notes on Meaning

• The term specifically denotes the taxonomic rank of 'class' within the biological classification system (Kingdom: Animalia, Phylum: Chordata). It is not a general descriptive phrase but a formal scientific name.
• It is contrasted with Class Chondrichthyes, the class of cartilaginous fish like sharks and rays.

Noun

1. a class of fish having a skeleton composed of bone in addition to cartilage