Exaggerated expectations in ancient starch research and the need for new taphonomic and authenticity criteria

Abstract

Ancient starch research illuminates aspects of human ecology and economic botany that drove human evolution and cultural complexity over time, with a special emphasis on past technology, diet, health, and adaptation to changing environments and socio-economic systems. However, lapses in prevailing starch research demonstrate the exaggerated expectations for the field that have been generated over the last few decades. This includes an absence of explanation for the millennial-scale survivability of a biochemically degradable polymer, and difficulties in establishing authenticity and taxonomic identification. This paper outlines new taphonomic and authenticity criteria to guide future work toward designing research programs that fully exploit the potential of ancient starch while considering growing demands from readers, editors, and reviewers that look for objective compositional identification of putatively ancient starch granules.

The application of 3D modeling and spatial analysis in the study of groundstones used in wild plants processing

“…Despite a limited size of our experimental sample, our results emphasize the spatial relation occurring between use wear and starch granules, overall contributing to the debate regarding the potential of ancient starch granules in interpreting groundstone use (e.g., Mercader et al 2018). The methodological approach presented herein underlines even more the importance of combining use wear and residue analyses in order to provide an adequate interpretation of the use of groundstone, in particular regarding their exploitation in plant processing.…”

“…on the tool surfaces was only described qualitatively (localization and distribution manner) with the naked eye. Starch have been extracted and analyzed following criteria known and widely accepted by modern and ancient starch analysts (Atchison and Fullagar 1998; Barton and Torrence 2015;Field et al 2009;Fullagar et al 2008;Haslam 2006;Henry et al 2009;Loy et al 1992;Mercader et al 2018; Torrence and Barton 2016; Yang and Perry 2013). We stress that the origin of the starch granules was known to us, and the scope of this work is to assess where larger masses of starch granules gather on the stone surface and assess where they appear more damaged.…”

“…Lumps were also recorded in term of size in order to reconstruct the number of granules stored in each of it, according to the average size of a single grain of the analyzed species. Experimental starch description was based on the geometric morphometric typology of the grains (Mercader et al 2018), position and form of the hilum, presence and appearance of surface features, depressions, fissures, presence of lamellae and extinction cross, birefringency, and specific distribution (e.g., bimodal distribution, presence/ absence of lumps) ( Haslam 2004;Horrocks et al 2004;Piperno et al 2000) (Table 5).…”

“…As a matter of fact, investigating spatial distribution of residues in relation to patterns of surface modification would allow one to better understand how activities and gestures in working these materials affect residue disposition on the used tools. As recently stressed by Mercader et al (2018), by allowing to discern between naturally adhered organic remains (e.g., sediments) and use-related ones, patterns of residue distribution over a tool's surface positively contributes to the debate regarding ancient contamination, Here, we present experimental data coming from the analysis of an assemblage of modern groundstones systematically utilized to process wild grain grasses, roots, and fruits. Our methodological approach focuses on the combination of 3D scanning performed through close range photogrammetry, spatial analysis, use wear, and micro-residue (namely starch granules) analysis.…”

“…For this reason, even though we focused our analysis on wild plant processing, our results highlight the potential application of this methodological framework in future works focusing on groundstones used in domestic plant processing. In a broader perspective, our work aims to contribute to the ongoing debate in the field of starch research regarding ancient contamination and authentication of starch granules (Crowther et al 2014;Mercader et al 2018), providing new means for strengthening the validity of this analysis in the study of ancient human behaviors.…”