Expedient shell scrapers in the Kingdom of Tonga

Shell has played a significant role as a raw material for tool manufacture in the South Pacific. Archaeological research on Lapita (2850-2650 cal. BP) sites in the Kingdom of Tonga recovered an assemblage of Anadara antiquata valves with what appears to be deliberate edge modification. These were collected, but at the time of collection, the origin of the shells was unknown. No other researcher had determined if these shells had been modified anthropogenically or whether the modification was the result of natural taphonomic processes. This study investigates whether or not the recovered valves represent a type of expedient shell tool, and if so, how they can be differentiated from naturally fragmented Anadara antiquata. The techniques used to assist in making these determinations include morphological analysis, a variety of experimental analyses, and a low power starch analysis.Taken together, the results of these analyses provide a robust case for the consideration of the valves as scraping tools, and further, they provide guidelines for identification of such artifacts in the field.