al.42 (link). Phytoliths were
identified and counted using a Zeiss Axioscope 40 light microscope at
500× magnification. Phytolith identifications were made using published
material for the Neotropics17 ,43 (link)–46 (link) and by direct comparison with the phytolith
reference collection of the Archaeobotany and Palaeoecology Laboratory in the
Department of Archaeology of the University of Exeter. A minimum of 200
diagnostic phytoliths were counted per slide. A full scan of the slides was
performed to detect the presence of squash, manioc and maize. Phytolith
assemblages in SW Amazonia have been studied in modern soils46 (link) and 29 paleosols from the
early and late Holocene15 (link) in
different natural environments and land covers. In none of these natural
contexts have phytoliths of Manihot or Curcubita been found, strongly suggesting
that phytoliths of these two genera found in FIs are the direct result of human
activity and not of the chance occurrence of wild relatives on these FIs