The paleontologist of the University of Flinders, in Australia, John Long reveals in a study published in Nature how the reproductive sex with penetration evolved in our most primitive ancestors. In one of the major discoveries in evolutionary biology to date, scientists have found evidence that internal fertilization and copulation appeared in an ancient species of prehistoric fish called placoderms , some 385 million years ago in the territory that today it's Scotland.
Fossil evidence found in this group of extinct jawed fishes of the genus Microbrachius shows that they copulated even though many of their descendants stopped doing so. This data could alter the history of sexual relations in animals. And it is that the research, carried out by an international team of scientists, places the origin of internal copulation at the beginning of the evolution of vertebrates and implies that external fertilization in prehistoric fish, such as free spawning, could have evolved later. .
"It was something unexpected," says John Long, lead author of the study, referring to the finding. "Before, biologists thought that there could be a reversal from internal fertilization to external fertilization, but we have shown that it has probably happened this way." Mind you, the researchers assume that more evidence is needed to show that this process was generalized and not just a specialized function of certain subgroups of placoderms .
Photo: Brian Choo / Flinders University
