Taxonomy
The relationship of lungfishes to the rest of the bony fish is well understood:
- Lungfishes are most closely related to Powichthyes, and then to the Porolepiformes.
- Together, these taxa form the Dipnomorpha, the sister group to the Tetrapodomorpha.
- Together, these form the Rhipidistia, the sister group to the Coelacanths.
The relationships among lungfishes are significantly more difficult to resolve. While Devonian lungfish had enough bone in the skull to determine relationships, post-Devonian lungfish are represented entirely by skull roofs and teeth, as the rest of the skull is cartilaginous. Additionally, many of the taxa already identified may not be monophyletic. Current phylogenetic studies support the following relationships of major lungfish taxa:
Class Osteichthyes
Subclass Sarcopterygii
Order Dipnoi
,--Family Diabolichthyidae (
extinct)
| ,--Family Uranolophidae (
extinct)
| | __,--Family Speonesydrionidae (
extinct)
'-|-| '--Family Dipnorhynchidae (
extinct) | ,--Family Stomiahykidae (
extinct) '----|___ ,--Family Chirodipteridae (
extinct) | '-|--Family Holodontidae (
extinct) |------Family Dipteridae (
extinct) | __,--Family Fleurantiidae (
extinct) '-| '--Family Rhynchodipteridae (
extinct) '--Family Phaneropleuridae (
extinct) | ,--Family Ctenodontidae (
extinct) '-| ,--Family Sagenodontidae (
extinct) '-|--Family Gnathorhizidae (
extinct) '--Order
Ceratodontiformes |--family Asiatoceratodontidae (
extinct) |--Family Ptychoceratodontidae (
extinct) |--Family Ceratodontidae | '--Genus
Ceratodus (
extinct) | '--Genus
Metaceratodus (
extinct) '--Family
Neoceratodontidae | '--Genus
Mioceratodus (
extinct) | '--Genus
Neoceratodus - Queensland lungfish '--
Order Lepidosireniformes '--Family Lepidosirenidae - South American lungfish '--Family Protopteridae - African lungfish