The infraclass, also called Dipneusti, consisting of the lungfishes. The Dipnoi plus the fossil infraclass Porolepimorpha make up the subclass Dipnotetrapodomorpha, one of five subclasses of the class Sarcopterygii. The extant lungfishes are in two orders as follows:

• Order Ceratodontiformes, Family Ceratodontidae
• Order Lepidosireniformes, Family Lepidosirenidae (South American lungfishes), Protopteridae (African lungfishes)