Published: Fri, August 11, 2017
Science | By Hubert Green

Alesi our 13m-year-old ancestor

Alesi our 13m-year-old ancestor

The tiny Alesi skull is 13 million years old.

Miller says scientists will continue research to see if they can learn even more about the baby ape's brain capacity and brain organization.

Scientists think the skull was from an infant ape that died in a forest and was subsequently covered by ash from a nearby erupting volcano.

"This discovery will help to fill in missing information regarding the adaptations that influenced ape and human evolutionary histories, and shed light on long-standing mysteries about at least one enigmatic ape species".

The discovery, made in Kenya, indicates what the common ancestor of all living apes and humans may have looked like. They found that numerous most informative parts of the skull are preserved inside the fossil, shedding light on how the common ancestor of all living apes and humans might have looked like.

The scientific journal Nature has published Dr. Nengo's findings in detail. In particular, Begun doesn't agree that Nyanzapithecines should be recognized as a distinct group, or that they were more modern than other known primates from the time, namely Proconsul (an extinct genus of primates that lived between 23 to 25 million years ago) and Ekembo (a similar genus that lived 20 to 17 million years ago).

Researchers have discovered a 13 million-year-old skull of a new species of ape, the most complete known fossil of its kind.

Our common ancestor with chimpanzees lived in Africa six to seven million years ago, and many spectacular fossil finds have revealed how humans evolved since then.

Other species in this genus, previously known from jaws and teeth, date to as early as around 25 million years ago.

But the inner ear helps researchers know that fossil comes from a period after monkeys and early apes diverged.

Kenyan fossil hunter John Ekusi discovered the skull in 2014 in the Napudet area, west of Lake Turkana in northern Kenya.

"We have a handsome ape cranium (skull) from a period that we knew virtually nothing about, and this is one of those wonderful cases where discovery leads to all sorts of new and interesting perspectives", says Craig Feibel, a professor of geology and anthropology at Rutgers University.

"We've been looking for ape fossils for years-this is the first time we're getting a skull that's complete", he added. Numerous most informative parts of the skull are preserved inside the fossil, and to make these visible the team used an extremely sensitive form of 3D X-ray imaging at the synchrotron facility in Grenoble, France.

"We were able to reveal the brain cavity, the inner ears and the unerupted adult teeth with their daily record of growth lines", Paul Tafforeau of the European Synchrotron Radiation Facility in Grenoble, France. The three-dimensional X-ray images taken of these adult teeth were so detailed that researchers could count their enamel layers, which were laid down over time like rings inside a tree, helping the scientists estimate that the baby primate was 16 months old when it died. They also said that several aspects of the new species link it to living apes.

"There was some discussion for a while about whether the modern apes actually originated in Africa or in Eurasia, because gibbons today live in Southeast Asia, and this pretty squarely confirms that the origin of apes was in Africa".

Researchers first thought Alesi had been a gibbon because it had a small snout.

"This gives the initial impression that it is an extinct gibbon", said Chris Gilbert of Hunter College, New York. Faces resembling gibbons evolved independently in several extinct monkeys, apes and their relatives, the researchers say. That means Alesi most likely moved more slowly and cautiously.

"Gibbons are well known for their fast and acrobatic behavior in trees", said Fred Spoor, of University College London and the Max Planck Institute of Evolutionary Anthropology.

© Isaiah Nengo, Photo by Christopher Kiarie.

"The majority of that group, and the oldest members of that group, are African but we would not have been able to resolve all of that without Alesi", said Nengo. The Leakey Foundation, the FoothillDe Anza Foundation, the Fulbright Scholars Program, the National Geographic Society, the European Synchrotron Radiation Facility, and the Max Planck Society funded the work.

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