Figure 1. Geographic sampling. Locations of the 19 Arabian Peninsula sampling sites, including eight from the Red Sea, five from the Arabian Sea/Sea of Oman, and six from the Persian/Arabian Gulf. Dark green shading represent the distribution of mangrove populations along the Arabian coasts, obtained from Spalding, Kainuma and Collins (12 ). Leaf tissue was collected from ten trees per sampling site for DNA extraction and whole genome sequencing. An eastern Australian population was also included as an outgroup (not shown).