Hierarchy classification:

1. top of the aat hierarchies
2. Agents Facet
3. Living Organisms (hierarchy name)
4. living organisms (entities)
5. Eukaryota (domain)
6. Animalia (kingdom)
7. Chordata (phylum)
8. Vertebrata (subphylum)
9. Osteichthyes (class)

Narrower term/s

• Dipnoi (order)

Anotations

Scope note:

Class of vertebrate fish characterized by lobed paired fins with a fleshy base over a bony skeleton and joined to the body by a single bone, persisting notochord, internal nares, and two dorsal fins with separate bases as opposed to the single dorsal fin of ray-finned fishes. They are extremely ancient in origin, appearing in the Lower Devonian about 390,000,000 years ago. They gave rise to amphibians. In some classifications, it is listed as a class instead of a subclass. Recognition of the subclass or class Sarcopterygii is controversial because some ichthyologists believe that the two major groups, the Crossopterygii (including the rhipidistians and coelacanths) and the Dipnoi arose from independent origins, given that the current structures of the two groups are widely divergent. The primitive members, however, show several similarities, supporting the view that they had a common ancestor.