Lungfish are freshwater fish belonging to the Subclass Dipnoi. While vicariance would suggest this represents an ancient distribution limited to the Mesozoic supercontinent Gondwana, the fossil record suggests that advanced lungfish had a widespread freshwater distribution and that the current distribution of modern lungfish species reflects extinction of many lineages following the breakup of Pangaea, Gondwana, and Laurasia. Image:Acanthodii.jpg This prehistoric fish-related article is a stub. You can help Fossil Wiki by [ expanding it].