Issues of phytolith taphonomy at Palaeolithic sites: Investigation and results from Attirampakkam, India

•Phytolith assemblages at Palaeolithic sites are vulnerable to taphonomy-related bias.•Morphotype redundancy and multiplicity complicate inferences about the fossil record.•Phytolith inventories in soil and 134 modern plant species were analysed and compared.•Grass, sedge and palm morphotypes were found to be the most reliable taxa.•The protocol provides a critical test for interpreting past land cover changes.