Ceratodus

Ceratodus is an obsolete taxonomic name formerly used to classify the Australian lungfish ( Neoceratodus forsteri). It was once believed to represent an extinct genus of lungfish separate from the living species. However, modern phylogenetic analysis has revealed that Neoceratodus forsteri is the sole surviving member of the Ceratodontidae family, and therefore, the genus Ceratodus is no longer considered valid.

The name Ceratodus was based on fossil teeth found in Europe and elsewhere, dating back to the Triassic period. These teeth were distinct in morphology and were initially believed to belong to a separate group of lungfish. As more complete fossils were discovered and studied, the relationship between these extinct forms and the Australian lungfish became clearer. It was realized that the differences were due to evolutionary changes within the lineage leading to Neoceratodus forsteri.

The term Ceratodus might still be encountered in older literature or paleontological contexts when referring to fossil lungfish teeth with a characteristic ridged, crushing surface. However, its use as a valid genus name is discouraged in modern scientific classifications. Current scientific practice involves classifying extinct lungfish based on more comprehensive skeletal features rather than relying solely on tooth morphology, which can be subject to convergent evolution. The history of the Ceratodus classification highlights the ongoing refinement of our understanding of evolutionary relationships through paleontological discoveries and phylogenetic analysis.