Sampling sites for Phelsuma species along the granitic and coralline Seychelles islands. Species and subspecies are coded using different symbols: dark blue triangles - P. astriata astriata; light blue triangles - P. astriata semicarinata; white triangle - P. astriata (Fregate population); dark green circles - P. sundbergi longinsulae; light green squares - P. sundbergi sundbergi; light green circles - P. sundbergi ladiguensis. Within the granitic islands (insets a and b), different shadings show areas that would be emerged at −30 m (dark grey) and −50 m (light grey) below present sea-level stands. Low-stands below 60 m would allow contact between all islands in this granitic group. Current data on Indian Ocean sea level changes support low-stands of up to 145 ± 5 m below present sea level (bpsl) at six episodes in the last 0.5 Myr, some of which persisted for up to 50,000 years at a time see  and geological records going back further suggest low-stands of 80–120 m bpsl at 0.64, 0.88, 1.04, 1.26 and 1.54 Mya, and eleven additional low-stand episodes of 50 m or more bpsl during the last 5 Myr . Detailed locations and accession numbers are given in Additional file 1.