Living Fossils - Queensland Lungfish
The Queensland Lungfish is the only surviving member of its Family, Ceratodonitidae, and the Order Ceratodontiformes. That doesn’t mean that there aren’t other lungfish, though! There are six extant species, including the Queensland Lungfish.
The Queensland Lungfish is a lobe-finned fish, sometimes called fleshy-finned fish, which is interesting enough because Tetrapoda descended from Sarcopterygii (Lobe-finned fish.) (Remember, evolution isn’t progress, it’s diversification through change through decent.) (See Tiktaalik song) It is one of the six extant species of Dipnoi (lungfishes) which flourished during the Devonian, and is the most primitive surviving member of Dipnoi. It can survive out of water for several days, but, unlike its four African cousins, it cannot survive total water depletion and must be kept moist. Fossils almost identical to the Queensland Lungfish have been found, indicating that it has remained nigh unchanged since 100 mya , and, therefor, is a viable living fossil.