OH 5 - Analysis

Analysis

Louis wrote "A new fossil skull from Olduvai" for Nature the week following the excavation, detailing the titular find and the "living floor" of Bed I which was replete with fossils of other mammalian fauna. "The Newest Link in Human Evolution: The Discovery by L.S.B. Leakey of Zinjanthropus Boisei", his account of the dig, was published in the January 1960 issue of Current Anthropology. It was annotated by anthropologist Francis Clark Howell, who had been allowed to examine the Leakeys' Olduvai findings before public announcements of their discovery.

Louis also wrote "Finding the World's Earliest Man" for the September 1961 issue of National Geographic, estimating the fossil's age to be 600,000 years old. University of California, Berkeley, geochemists Garniss Curtis and Jack Evernden used potassium-argon dating to re-assess the site, finding that Olduvai's Bed I was actually about 1.75 million years old. Such an application of geochronology was unprecedented; OH 5 became the first hominin to be dated by that method. The same process was used for OH 7, the holotype of Homo habilis (handy man).

After the cranium was reconstructed with a model of the absent mandible, contemporaneous newspapers referred to it as "Nutcracker Man" due to the large posterior teeth and jaws which gave it a resemblance to vintage nutcrackers. Phillip Tobias, a colleague of the Leakeys, has also received attribution for this nickname. Primitive tools fashioned out of rocks and bone were excavated at and around Olduvai's Bed I, sometimes called the FLK Zinjanthropus site since the finding of OH 5.

Louis initially believed P. boisei to be a direct ancestor of modern humans (as evident from the title of his National Geographic article) and the maker of those tools found near its remains, but he withdrew this idea once he and Mary unearthed Homo habilis – which had a larger brain – in the same area less than two years later. Despite that, OH 5 made the Leakeys famous and brought more attention to the developing field of paleoanthropology. The cranium was taken to Kenya after its discovery and was there until January 1965 when it was placed on display in the Hall of Man at the National Museum of Tanzania in Dar es Salaam. It remains there as of 2009, still recognized by the name Zinjanthropus, or simply Zinj.