Fig. 1

Biogeographical and phylogenetic reconstruction, and haplotype network. Legend: A phylogenetic tree for the four monophyletic focal species and one ingroup species (X. bispinatus) constructed using COI and EF1α. The phylogeny was constructed with sequences from 12 species as outgroup (Additional file 1: Table S3), which were removed from this figure. Posterior probability values are indicated by asterisks on nodes (*PP >0.95); numerous less important, yet strongly supported nodes (i.e., nodes nested deep within clades; PP >0.95), are not presented. Scale bars indicate branch length, which correspond to number of substitutions. Pie charts on branches show the relative probabilities of different geographical regions from the ancestral reconstruction. Circle sizes on trees contain no information, whereas circle sizes in the haplotype networks indicate number of individuals per haplotype. The haplotype networks shown here are based on COI only. Colour codes indicate regions, as shown in the bottom right corner, and are the same for pie charts in branches and in networks. Scale bars in the haplotype networks show the relationship between number of substitutions and branch lengths (these differ slightly among the haplotype networks)