An article published in the journal “Science Advances” reports a study of the known fossil skull of Chilecebus carrascoensis, an extinct monkey that lived about 20 million years ago, in the Miocene period, in today’s Chile. A team of researchers subjected it to a high resolution CT scan to obtain a 3D digital reconstruction that allowed to study its internal structure and therefore the brain’s structure. The new information on this primitive relative of monkeys and hominids that evolved later suggest that the evolution of these primates’ brains was non-linear and that it grew several times independently.