With the discovery of living things that refuted the thesis regarding the transition from water to land, evolutionists clutched at other theories on the subject. (See Coelacanth.) Some evolutionists regarded lunged fish as the ancestors of all terrestrial animals. The general name given to these fish that are able to use their lungs as well as gills is Dipneuma. There are three different species of these fish living in the seas around America, Africa and Australia.
Since the 1850s, it was actually thought that these fish had evolved into primitive amphibians. By the 1950s, however, they ceased being regarded as transitional forms because they were very exceptional specimens. By that time no one any longer supported the idea that they were the ancestors of terrestrial life forms.128
Since 1930’s, the Dipneuma assumption has been put aside gradually. When the final years of 1950’s were reached, organisms with double respiratory features was characterized as very exceptional by a paleontology publication known to be a classic.129
In addition, the fact that the fossil remains of these fish are regarded as being 350 million years old, and have undergone no change at all in that time, also removed their candidacy as transitional forms. These animals are not transitional links between two species that subsequently disappeared, but distinct species that have been alive since very early times.
128 Jacques Millot, “The CCFlacanth.” Scientific American, December 1955, Vol. 193, p. 39.
129 Maria Genevieve Lavanant, Bilim ve Teknik, April 1984, No. 197, p. 22.