Phylogenetic relationships of nautilids based on maximum-likelihood analysis of 18,595 concatenated SNPs with IQtree as in Combosch et al. (2017). Numbers on nodes indicate ultrafast bootstrap resampling percentages (>50) based on 1000 replicates–asterisks indicate full support (* = 100%). Bootstraps values were replaced on intraclade nodes as follows: “-” for bootstraps values >50 – <90, “+” for bootstrap values ≥90. Colors correspond to geographic populations as indicated in the map on the bottom left. Species other than Nautilus pompilius are indicated by name at the tip of the tree. The STRUCTURE plots show the posterior probability for individual assignments of samples to different genetic clusters in clade-specific analyses. Distinct colors indicate different genetic clusters as inferred by STRUCTURE (not populations as on the tree and map).