δ18Oc-δ18Op differences between teeth and bones plotted against the structural carbonate content (wt%) of apatite. Samples that have δ18Oc-δ18Op differences higher than 14.7‰ are considered doubtful as regards potential diagenetic alteration (see text). For carbonate contents (wt%) higher than 13.4%, the δ18Oc values are considered to be inherited from inorganic diagenetic processes. A high difference between δ18Oc and δ18Op is interpreted as the result of a microbially-mediated alteration of the apatite phosphate or too high δ18Oc values resulting from the addition of inorganic carbonate or isotopic exchange with an external source of inorganic carbon. The grey crosses refer to previously published South African bone and tooth samples (Rey et al., 2016).