Definition

Noun: * A taxonomic subclass of bony fish (class Osteichthyes) comprising the lungfishes. These are freshwater fish characterized by having both gills and a modified air bladder that functions as a lung, allowing them to breathe air. They are considered evolutionarily significant as they share characteristics with both fish and amphibians.

Usage Examples

• Noun:
  • The subclass Dipnoi includes species like the Australian and South American lungfish.
  • Fossils show that the subclass Dipnoi has existed for hundreds of millions of years.
  • Biologists study the subclass Dipnoi to understand the transition from aquatic to terrestrial life.

Advanced Usage

• In taxonomic hierarchy: The term is used in formal scientific classification. For example: "The species belongs to the order Ceratodontiformes, which is within the subclass Dipnoi."

Variants and Related Words

• Dipnoi (noun): Often used interchangeably as the common name for the group, especially in less formal scientific contexts. (e.g., "The Dipnoi are a small group of fish.")
• Dipnoan (adjective/noun): Relating to or characteristic of the subclass Dipnoi; a member of this subclass. (e.g., "dipnoan anatomy," "a dipnoan fossil").
• Lungfish (noun): The common name for the fish belonging to the subclass Dipnoi.

Synonyms

• Lungfishes (common name)
• Dipnoans (scientific common name)

Different Meanings

• This term has a single, specific meaning in zoological taxonomy. It does not have general English usage outside of scientific contexts.

Noun

1. bony fishes of the southern hemisphere that breathe by a modified air bladder as well as gills; sometimes classified as an order of Crossopterygii