Lungfish are freshwater fish belonging to the order Dipnoi. Lungfish are best-known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed internal skeleton. Today, they live only in Africa, South America, and Australia. While vicariance would suggest this represents an ancient distribution limited to the Mesozoic supercontinent Gondwana, the fossil record suggests that advanced lungfish had a cosmopolitan freshwater distribution and that the current distribution of modern lungfish species reflects extinction of many lineages following the breakup of both Pangea and subsequently Gondwana and Laurasia. Anatomy and morphology All lungfish demonstrate an uninterrupted cartilaginous notochord and an extensively developed palatal dentition. Basal lungfish groups may retain marginal teeth and an o