Hammerstone

Abstract: Since stone tool cut marks and carnivore tooth marks were first described systematically on Plio-Pleistocene archaeological bone1,2, bone surface modification has played a prominent role in interpreting early archaeological site formation and hominid behaviour3–15. Here we introduce a new class of bone surface modification, which we call percussion marks. Percussion marks were produced during experimental breakage of marrow bones, and occur as pits or grooves impressed on a bone's surface by natural protrusions on the granitic hammerstone and anvil used. Although percussion marks can superficially mimic carnivore tooth marks, they nonetheless are closely associated with hammerstone impact notches and show consistent micromorphological features which distinguish them from tooth marks and other classes of bone surface modification. Given indications of prehistoric hammer-stone breakage of marrow bones1,7, an awareness of percussion marks is critical for accurately identifying the biological agents of bone modification at archaeological sites and provides a new diagnostic of carcass processing by hominids.

Abstract: Recently, Alcantara Garcia et al. (in press) presented a new method and criteria for distinguishing between fractures imparted by hominid hammerstone percussion and carnivores chewing on ‘green’ limb bones of ungulates. The method uses a combination of fracture plane and fracture angle data that are useful for elucidating the relative role of hominids in the accumulation of prehistoric archaeofaunas, especially when employed in concert with other classes of taphonomic data. We briefly summarise the method and apply it to the ungulate limb bone subassemblage from Swartkrans Member 3, a c. 1.0 million year old site from South Africa that preserves Early Stone Age lithic artefacts, hominid fossils, and an abundant mammalian fauna with cutmarked, hammerstone-percussed and burned bone specimens. Results of the fracture pattern analysis corroborate indications from other lines of taphonomic data that there was minimal carnivore–hominid interdependence in the formation of the fauna, and that carnivores were probably responsible for the majority of the bone collection in Member 3. However, we also document a significant hominid influence on assemblage formation, a finding that expands and refines our understanding of large animal carcass foraging by hominids in southern Africa during the early Pleistocene. Copyright © 2004 John Wiley & Sons, Ltd.