LOS ANGELES - The middle-aged woman and the boy, perhaps her son or simply another member of her tribe, were out hunting on the African plains or maybe hunting for water when they fell into a sinkhole, dying almost instantly.
Shortly thereafter, a monsoon or a flood washed them into a deeper basin, where they were covered with mud and rapidly fossilized.
In 2008, nearly 2 million years later, anthropologists discovered their nearly complete skeletons in the Malapa cave north of Johannesburg, South Africa, a find experts call one of the most important of recent times. The hominid pair may be direct ancestors of humans or they may be from a closely related branch on the human evolutionary tree, researchers reported yesterday in the journal Science.
The discovery of nearly intact skeletons, experts agree, provides a window into evolution during one of the key periods of human development, when hominids were changing from the apelike species known as Australopithecus into the more modern forms we know as Homo.
The new skeletons are the only complete specimens that lie between the Australopithecus afarensis known as Lucy, from 3 million years ago, and the Homo erectus known as Turkana boy from 1.5 million years ago.
The researchers have Google Earth and another boy, Matthew, 9, son of paleoanthropologist Lee R. Berger, to thank for the discovery. Berger, from the University of the Witwaters- rand in Johannesburg, used images from Google Earth to identify caves in the Cradle of Humankind World Heritage Site that might hold fossil deposits.
On their first visit to the Malapa cave, Matthew found a block of stone bearing a hominid collarbone and a jawbone.
Excavation uncovered the rest of that skeleton, of what appears to be an 11- to 12-year-old boy and another of a woman in her mid-30s, as well as skeletons of at least 25 species of animals, including antelope, mice, saber-toothed cats, a wildcat, a brown hyena, a wild dog and a horse.