Vascular organization of lungfish, a landmark in ontogeny and phylogeny of air-breathers

Dipnoan lungfish have evoked considerable interest over the last two centuries. These fish belong to a subclass of osteichthyes which flourished during the early Paleozoic era. This subclass comprises only three surviving genera: Neoceratodus (Australia), Protopterus (Africa), and Lepidosiren (South America).