One of Dibble's students was the first to notice a piece of bone the size of a quarter, said Dibble, who is a curator at the University of Pennsylvania Museum of Archaeology and Anthropology. To everyone's surprise, the bone was part of a remarkably complete skull and upper body of a child that died 108,000 years ago, as shown by various dating techniques.
The work was funded by National Geographic, whose cable channel will present a special program at 8 p.m. Thursday based on the finding, titled The World's Oldest Child.
From analyzing the teeth, Dibble's team estimated he or she was 6 to 8 years old. Dibble bestowed the name Bouchra, meaning good news in Arabic. It's a feminine name, but he has since decided it's more likely to have been a boy.
Dibble's team has yet to release the skull to the scientific community, nor have team members published peer-reviewed papers. But they say it's remarkably complete. Experts are eager to see it, hoping for a look back into a pivotal period.
In that earlier time, 108,000 years ago, modern Homo sapiens - people who looked like us - had emerged in Africa and begun to spread to the Middle East. Neanderthals populated parts of Eurasia. Africa was thought to be a patchwork of so-called modern Homo sapiens and somewhat different-looking "archaic humans."
"This will fit into the global debate on how and where and when modern humans arose," Dibble said.
"It joins a very small sample of hominid remains in Africa from that period," said archaeologist Curtis Marean of Arizona State University. "We don't know a lot about human populations at that time."
The young age of the child is also of scientific interest, he said. "As far as I know, this is the first juvenile from that crucial time period."
Dibble said he had seen people get worked up over a possible glimpse of bone before "and it's never anything." This time his team had gotten lucky.
The Moroccan site, called Smuggler's Cave, was home to a group of people who ate rabbits, gazelles, and seafood, and made some of the world's earliest art in the form of shell beads, Dibble said.
The only earlier evidence for art is the use of ochre pigments in southern Africa, he said. Neanderthal people by that period had begun to bury their dead, but left no evidence for any form of symbolic communication or art.
The child had bigger teeth than a person would have today - a trait that's also seen in some of the first modern humans to venture out of Africa. "They looked like us but not exactly like us," Dibble said.
Some think it's possible this child's people were part of our ancestry, thanks to climate changes that let people move and mix throughout Africa.
Anthropologist Jean-Jacques Hublin, who helped Dibble characterize the skull, said that while the focus had always been on southern Africa, north Africa may prove as important.
"Maybe instead of a little garden of Eden in South Africa as the source population for extant humans, the situation in Africa 100,000 years ago was more complicated, with many other groups showing evolution toward what we call behavioral and anatomical modernity," said Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
One thing that impresses Hublin is that the shell beads from Morocco and southern Africa are made from similar species. "It's amazing to think that at the distance of several thousand kilometers, humans had been developing behaviors that are so similar."
The child may also help scientists better understand the evolution of humanity's uniquely long childhood. Chimpanzee mothers breastfeed their babies until they are about four, said Hublin, but after that, the little chimps can find food themselves. "Humans have a completely different strategy," he said, which requires members of extended families or tribes to help women and their children stay fed. "The question is, did this pattern emerge recently in the course of human evolution or is it something that is old and emerged gradually?"
Hublin believes Neanderthal children grew up faster, with an 8-year-old Neanderthal equivalent in maturity to a 12-year-old modern human. They hit puberty earlier and started reproducing at 14 or 15, he said.
Anthropologist Erik Trinkaus of Washington University in St. Louis said there wasn't enough evidence one way or the other to know if Neanderthals had an extended childhood just as we do.
Trinkaus says he hopes the new finding will reveal if the people of this time and place were anatomically modern humans or archaic Homo sapiens.
Archaic people had somewhat different features - including a brow ridge or lack of a chin. But they may have been ancestral to us since these populations were capable of interbreeding.
And while he hasn't seen the child yet, he thinks it could add to our emerging story of humanity's origin and early history. "It's a group of humans living in a peripheral area of the world, in some ways adapting to a harsh environment," he said. There were Neanderthals living just across the Strait of Gibraltar, in Spain, and some of the tools in Morocco resemble Neanderthal tools from Spain.
Hublin doesn't think the region is necessarily peripheral. "Emphasis has been put so much in south Africa because this is where we had data. But it's like the story of the drunk man looking for his keys - he doesn't look in the dark."
So perhaps this child could add some light.
Contact staff writer Faye Flam
at 215-854-4977 or firstname.lastname@example.org.