Known distribution of Calamaria gervaisii in the PhilippinesKnown distribution of Calamaria gervaisii in the Philippines. The five recognized major Pleistocene aggregate island complexes (PAICs), major islands and island groups, and additional deep-water islands are labeled for reference. Red dots indicate localities where the species has been observed. Red islands indicate the species is recognized to occur throughout the island. Red dashed lines indicate hypothesized geographic distributions. Red gradients indicate hypothesized geographic distributions, with darker shades indicating higher confidence in the species distribution. Current islands in the Philippines are shown in medium gray (or red); light gray areas enclosed in black 120-m bathymetric contours indicate the hypothesized maximum extent of land during the mid- to late Pleistocene.