For a long time, paleontologists were convinced that coelacanths, robust fish very common in the Carboniferous oceans 350 million years ago, had disappeared in the Cretaceous, around the same time as the last dinosaurs. Therefore, the discovery at the end of 1938 of a living specimen in the Indian Ocean caused a great surprise.
Now, a study published in the journal Nature Communications highlights that, although coelacanths use their gills to breathe, these animals of about two meters of lake also have a lung located in their abdomen , although it is a vestigial organ that has lost its function; something similar happens, in essence, with the human appendix. According to the essay, a team of researchers from the Rio de Janeiro State University carried out a series of 3D recreations in which they analyzed five phases of the vital development of a species of coelacanth called Latimeria chalumnae .
Thus, the scientists found that in the embryonic phase it had a perfectly developed lung that, however, stopped growing shortly thereafter, probably as a consequence of the fish's adaptation to a deeper environment. The researchers suggest that perhaps this adaptive mechanism allowed them to survive the great Cretaceous extinction 65 million years ago.
