When Paul C. Sereno went hunting for dinosaur bones in the Sahara, his career took a sharp turn from paleontology to archaeology. The expedition found what has proved to be the largest known graveyard of Stone Age people who lived there when the desert was green. The first traces of pottery, stone tools and human skeletons were discovered eight years ago at a site in the southern Sahara, in Niger. After preliminary research, Dr. Sereno, a University of Chicago scientist who had previously uncovered remains of the dinosaur Nigersaurus there, organized an international team of archaeologists to investigate what had been a lakeside hunting and fishing settlement for the better part of 5,000 years, originating some 10,000 years ago. In its first comprehensive report, published Thursday, the team described finding about 200 graves belonging to two successive populations. Some burials were accompanied by pottery and ivory ornaments. A girl was buried wearing a bracelet carved from a hippo tusk. A man was seated on the carapace of a turtle. The most poignant scene was the triple burial of a petite woman lying on her side, facing two young children. The slender arms of the children reached out to the woman in an everlasting embrace. Pollen indicated that flowers had decorated the grave. The sun-baked dunes at the site, known as Gobero, preserve the earliest and largest Stone Age cemetery in the Sahara, Dr. Sereno's group reported in the online journal PLoS One. The findings, they wrote, open “a new window on the funerary practices, distinctive skeletal anatomy, health and diet of early hunter-fisher-gatherers, who expanded into the Sahara when climatic conditions were favorable.” The initial inhabitants at Gobero, the Kiffian culture, were tall hunters of wild game who also fished with harpoons carved from animal bone. Later, a more lightly built people, the Ténérians, lived there, hunting, fishing and herding cattle. Other scientists said the discovery appeared to provide spectacular evidence that nothing, not even the arid expanse of the Sahara, was changeless. About 100 million years ago, this land was forested and occupied by dinosaurs and enormous crocodiles. Around 50,000 years ago, people moved in and left stone tools and mounds of shells, fish bones and other refuse. The lakes dried up in the last Ice Age. Then the rains and lakes of a fecund Sahara returned about 12,000 years ago, and remained, except for one 1,000-year interval, until about 4,500 years ago. Geologists have long known that the region's basins retained mineral residue of former lakes, and other explorers have found scatterings of human artifacts from that time, as Dr. Sereno did at Gobero in 2000. “Everywhere you turned, there were bones belonging to animals that don't live in the desert,” he said. “I realized we were in the green Sahara.”
