Fig. 2From: Metagenomic analysis of ancient dental calculus reveals unexplored diversity of oral archaeal MethanobrevibacterTaxonomic analysis of the microbial composition of the ancient dental calculus samples collected. A MetaPhlAn heatmap of the top 25 species found in the ancient calculus. B Species-level principal coordinate analysis (PCoA) of β-diversity (Bray-Curtis distances) considering the microbiome from ancient calculus (this study) [5, 6, 11, 13, 31] modern calculus [13], plaque and tongue dorsum (HMP) [33]Back to article page