A taxonomy of Javan hominid mandibles

The mandibular remains from Java have been controversial since the discovery of Kedung Brubus (Mandible A) in 1890. These mandibles, now called Kedung Brubus, and Sangiran 1, 5, 6, 8, 9, and 22, have been assigned to a wide variety of taxa. It is now commonly accepted that all seven mandibles can be accommodated in a single species;Homo erectus. A recent assessment to this effect was performed by Kramer (1989). Utilizing powerful statistical techniques he distinguished the Sangiran mandibles from the robust australopithecines and placed them all withinH. erectus. The jaws are not a homogeneous sample. Morphologically they are a mixture ofAustralopithecus africanus («Homo habilis») males (5,6), anA. africanus («H. habilis») female (8),H. erectus males (1,9), and aH. erectus female (22) and Kedung Brubus. The dating of these fossils remains unresolved, with a minimum date of 500,000 ya and a maximum of 1.6 mya. Any of the mandibles may have been transported and secondarily redeposited. If the jaws are allH. erectus then they have a sexual dimorphism exceeding that of modern gorillas. When Kedung Brubus is included with those from Sangiran the range of size dimorphism is well beyond that known for any primate, thus more than one species may be invloved. This dimorphism is found inA. africanus («H. habilis») but not inH. erectus samples anywhere else in the world. TheH. erectus skulls found in Java correspond with mandibles 1, 9, and 22. It is not likely that the largest mandible (6) is aH. erectus, because the skull would have had heavy temporal lines and probably a sagittal crest, neither of which is found on anyH. erectus specimen. But, a cranium has been found which morphologically matches the Sangiran 6 mandible. A double sagittal crest is present on Sangiran 31 a reported «Meganthropus» specimen.