Ceratodontinae

Ceratodontinae is a subfamily of lungfish belonging to the family Ceratodontidae. This subfamily is notable for containing the only extant lungfish in the world, the Queensland lungfish (Neoceratodus forsteri). Historically, the fossil record indicates a much wider distribution and greater diversity of ceratodontine lungfish, with numerous extinct genera and species found across Gondwana and later across Africa, South America, and Australia. These ancient lungfish played a significant role in freshwater ecosystems for millions of years.

The defining characteristics of Ceratodontinae, both living and extinct, include the presence of single, epiphysealless lungs, which are a key adaptation for surviving in oxygen-poor waters. They possess paired lobed fins and a continuous dorsal, caudal, and anal fin. Fossil ceratodontines are often identified by their distinctive dental plates, which are fused teeth forming powerful grinding surfaces. The evolutionary lineage of Ceratodontinae traces back to the Triassic period. The continued existence of Neoceratodus forsteri in Australia represents a remarkable example of a living fossil, offering insights into the biology and evolutionary history of ancient sarcopterygian fish. The subfamily's distribution has drastically contracted over time, with only one representative surviving in a limited geographic range.