Top 5 Human Evolution Discoveries of 2017 (PLOS)
A new species of ancient ape, Nyanzapithecus alesi
In a publication in Nature on August 10, 2017, Dr. Isaiah Nengo, Turkana Basin Institute, and De Anza College and his team from the National Museums of Kenya introduced the world to “Alesi”. Alesi is an infant ape skull, roughly the same size as a baseball, but with a big impact! This 13 million year old skull, found in the Napudet area west of Lake Turkana in northern Kenya, is from a new species named or Nyanzapithecus alesi and represents a time that researchers know very little about: when the last common ancestors of modern humans and all other living apes were around. While bits and pieces of fossil apes have been found over the years, this is one of the only intact skulls. This makes Alesi not only incredibly rare, but also incredibly useful. Skulls give us detailed insight into brain size – from the size of the cranium, the age the individual was when it died and what it ate – from the teeth, as well as vision and hearing – from the eye sockets and small ear bones. Researchers got not just one, but two important dates from this amazing find. The first is the time in earth’s history during which this small individual was alive: roughly 13 million years ago, determined from dating volcanic minerals surrounding the fossil. The second is how old the individual was when it died: about 16 months old, determined by using specialized X-ray technology at the European Synchrotron Radiation Facility in Grenoble, France. The synchrotron can scan and count the growth rings in Alesi’s unerupted teeth to figure out how long this baby ape had been growing when a nearby volcano buried her along with the forest she lived in, much like how scientists can count tree rings to determine how long a tree has been growing. It was the synchrotron scans of the unerupted adult teeth and ear canals that clinched the identification of the fossil as a nyanzapithecine – an extinct sister group to humans, great apes, and gibbons.