An infant ape cranium named as “Alesi”, excavated from the site of an archaeological dig at Napudet, west of Lake Turkana in Kenya.
Scientists have named a new species of ape based on a 13-million-year-old skull fossil.
It belonged to a new species called Nyanzapithecus alesi that was closely related to the common ancestor of people and modern apes although that ancestor likely was even older, University College London paleontologist Fred Spoor said.
The sole specimen is that of an infant that would have grown to weigh about 11 kilogrammes (24 pounds) in adulthood. Its adult brain volume would have been nearly three times larger than that of known African monkeys from the same time, the researchers estimate.
“If you compare to all living things, it looks most like a gibbon“, study co-author Isaiah Nengo of the Stony Brook University in NY told AFP. The same probably held for N. alesi, making it an unlikely direct ancestor of living gibbons, they conclude.
The skull may answer a long-standing question about the origin of the lineage that led to people and modern apes such as chimpanzees, gorillas, orangutans and gibbons, indicating their common ancestor evolved in Africa, not Eurasia, the scientists said.
The lemon-sized skull was found in Kenya by an global team of researchers, and was dated to the middle of the Miocene era, a little-understood time when many species of ape arose in Africa, including common ancestors of both modern apes and humans.
“With this we put the root of the hominoidea in Africa more firmly“, said Nengo.
Scientists assigned it to a new species, Nyanzapithecus alesi. If an evolutionary relationship existed with the older N. alesi, the first members of the Oreopithecus genus probably originated in Africa, Nengo proposes.
That group, which has no official name yet, lived and died millions of years ago.
As well as dating to the “dark ages” of human origins, it is also the most complete extinct ape skull in the fossil record.
“Alesi is the one that has allowed us to. know who is in that group. and when we take a close look we see that most of the group are found in Africa“.
The record of African fossil hominoids (primates that include apes, humans and their ancestors) lacked a almost complete cranium from between 17 million and 7 million years ago, the study notes.
“We have a handsome ape cranium 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“, Craig Feibel, who chairs Rutgers’ Department of Anthropology and is a professor of geology and anthropology, said in a statement.
The skull resembles a baby gibbon’s. But the balance organ inside its inner ear differed from gibbons and suggested Alesi’s species moved through trees more cautiously and had shorter arms than gibbons, which swing through trees with acrobatic ease.
Growth lines on the adult teeth showed Alesi was one year and four months old at death.
Commenting on the study, anthropologist Brenda Benefit of the New Mexico State University described this as a fossil find “that I never thought would be made during my lifetime“.
“It’s a major finding that fills a large gap in the evolutionary record“.
“This is an exceptional discovery“, agreed Paul Tafforeau of the European Synchrotron Radiation Facility in Grenoble, France, who helped examine the skull.
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