Fossil skull of Chilecebus carrascoenis, a 20 million year old primate from the Andes.
Photo: AFP PHOTO / AMERICAN MUSEUM OF NATURAL HISTORY / N. WONG AND M. ELLISON / Profimedia
Human evolution is a fascinating process in which missing pieces of the puzzle are still occasionally added. One of these are the remains of a prehistoric primate that lived in the Andes 20 million years ago. It was so incredibly small it fit in a human palm. This discovery is now helping scientists shed light on how the human brain evolved, following the example of primate brain development.
Primates are generally divided into two groups: the Old World, from which our species originated, and the New World species in the Americas and Oceania. Each group is specific and in both we see different episodes of brain expansion. “In some groups, we see several episodes of actual reduction in relative brain size “, said the scientist John Flynn from the American Museum of Natural History, whose team discovered the fossil skull in the Chilean Andes in 1995.
At the same time, a new study has brought a surprising discovery. The brain size of primates, long thought to have gradually increased over time, appears to have undergone a deviation.
Watch a video about this monkey here:
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Source: Youtube
The skull “spoke” after nearly 30 years
Scientists from China and the United States used high-resolution images to examine the only known fossilized skull of the extinct Cilecebo. This is a New World monkey that was about the size of today’s tamarin. It lived mainly in mountain forests and fed on leaves and fruits. His brain had several grooves known as folds, indicating a higher degree of cognitive complexity. That said, this little monkey is proof that brain size isn’t always associated with maturity.
Cilecebus.
The little chilecebus provided a great find
New research was conducted Xijunem Ni of the Chinese Academy of Sciences. The fossilized skull has been precisely dated because it was discovered among volcanic rocks. By including the species in its larger family tree, it was inferred that brain enlargement occurred repeatedly and independently in the evolution of anthropoids.
In modern primates, the sizes of the visual and olfactory centers of the brain are inversely related. This means that species with strong eyesight usually have a weaker sense of smell and vice versa. But it was in Chilecebus that a small olfactory bulb did not lead to a stronger sense of smell. This proves that the two abilities are not related in any way, which is a new discovery.
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Monkey Skull rewrites history
It turns out that neither the location nor the size of the fossil record matter. A 20-million-year-old monkey skull that fits in the palm of an adult’s hand may contain remnants of partial brain development in ancient primates.
Human history can be rewritten even with a tiny discovery that provides new information. “This extraordinary discovery at an altitude of 10,000 meters in the Andes has helped to shed light on the development of our history. As you can see, each discovery can test previous hypotheses … (and) be able to understand the evolution of brain complexity in primates. “ He added John Flynn. A really well-preserved fossil thus helped to change the hypothesis. Thanks to her, it became clear that the brain regions of primates developed separately. Digital reconstruction also suggests that organ development over time has been complicated, as this video shows:
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Source: Youtube
The study concludes with new evidence that the primate brain, which includes humans, evolved gradually, rather than increasing overall size over time. Paleontologist Xijun Ni argues that the primate visual system has become larger and more complex over millions of years without requiring substantial changes in other parts of the brain. Major brain structures have evolved at different rates in different primate lineages. Likewise, the size of the brain increased in proportion to the size of the body.
“New findings from Nio’s group on the cerebral organization of the C. carrascoensis monkey suggest that the great diversity of neural folding patterns we observe today in New World monkeys, which outweighs the diversity of these patterns in the brains of modern African and Asian monkeys. , has deep evolutionary roots “. concludes the biological anthropologist Benefit Brenda.
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