Using high-resolution x-ray computer imaging technology, scientists from Duke University and the Max Planck Institute for Evolutionary Anthropology have been able to construct a 3-D model of the brain that was once housed in a 15-million-year-old monkey skull.
The ancient monkey skull belongs to the species of Old World monkeys known as Victoriapithecus, which includes baboons and macaques. The skull was originally found in 1997 in Lake Victoria in Kenya.
15-Million-Year-Old Secrets Uncovered
A study co-authored by Lauren Gonzales of Duke University and Fred Spoor of the Max Planck Institute for Evolutionary Anthropology sheds some light on some long-held secrets of the ancient skull.
Prior to their research, it was commonly thought and generally accepted that primate brains first grew in size, and then in complexity. However, the 3-D brain image that they were able to construct after using high-resolution x-ray imaging, shattered those previously accepted notions.
Their findings indicated that contrary to what had previously been believed of brain development in primates, the brain belonging to the 15-million-year-old monkey skull was actually quite complex despite being so small. Compared to modern-day monkeys of similar body size, the Victoriapithecus brain was estimated by Gonzales and Spoor to have only been about 36 cubic centimeters, less than half of their modern day counterparts.
The Complexities of a 15-Million-Year-Old Brain
What was truly fascinating about Gonzales and Spoor’s findings is the composition of the 15-million-year-old monkey skull’s brain. Their CT scans showed that the tiny brain housed in the ancient skull actually had a plethora of wrinkles and folds, indicating a vastly complex brain. In addition to the many wrinkles and folds, however, another stunning discovery was made.
The 3-D model showed that the olfactory bulb, which is the part of the brain used to perceive and interpret smells, was actually quite large. It had a size that was three times bigger than expected of a primate of that size, indicating that its sense of smell was highly elevated compared to primates of today. In comparison, primates of today have much larger brains, but much smaller olfactory bulbs. It is believed that this is due to a trade-off that occurred as sight improved over time.
The researchers believe that this means that the ancient primate that the 15-million-year-old monkey skull belonged to–quite possibly–did not have to make such a trade-off and instead had held on to both senses.
Implications of the Monkey Skull Discovery
The findings were published in the July 3 issue of Nature Communications, and despite dealing with something as ancient as a 15-million-year-old monkey skull, they are important because they are the only clues unearthed so far as to how primate brains developed over time. They also hint that the small brain size of the human ancestor homo floresiensis, the skull of which was discovered in Indonesia in 2003, isn’t as profound as had previously been thought. The findings of the study on the 15-million-year-old monkey skull and its brain will pave the way for future researchers looking into the development of primate brains over the course of history.
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