Historical evidence of the 1936 Mojokerto skull discovery, East Java

To resolve ambiguities in the literature, we detail the discovery history of the Mojokerto child's skull (Perning 1), employing letters, maps, photographs, reports, and newspaper accounts not previously used for this purpose. Andoyo, an experienced vertebrate-fossil collector with the Geological Survey of the Netherlands Indies, found the skull on February 13, 1936, while collecting for Johan Duyfjes, who had mapped the field area geologically. On February 18-19 Andoyo sent the fossil and a 1:25,000-topographic map showing the discovery point to Survey headquarters. The locality lies between Perning and Sumbertengu villages, approximately 10km northeast of Mojokerto city, East Java. G.H. Ralph von Koenigswald, Survey paleontologist, identified the specimen as Pithecanthropus and then named it Homo modjokertensis (it is now accepted as Homo erectus). Unfortunately he confused the discovery record in a March 28 newspaper article by characterizing the skull as a "surface find" [Dutch: oppervlaktevondst] while also attributing it to ancient beds. von Koenigswald probably had insufficient basis for either assertion, having not yet talked to Andoyo or Duyfjes. Eugene Dubois challenged von Koenigswald on the "surface-find" issue, Andoyo was consulted, and Duyfjes went to the site. Duyfjes and von Koenigswald then published scientific papers stating that the skull was unearthed 1m deep from a hill-slope outcrop of conglomeratic sandstone in Duyfjes' Pucangan formation. A cross section by Andoyo, which may show the Mojokerto site, also indicates a skull at 1m depth in conglomeratic sandstone. Photographs taken in 1936-1938 show a shallow pit at a single field location that fits Duyfjes' site description and is identified as the Mojokerto-skull site in 1940-1943 publications. By WWII the scientific community accepted the skull as an early hominid. Although von Koenigswald's "surface-find" comment remains a source of doubt in the record, we consider in situ discovery for the Mojokerto skull to be very likely.