Figure legends
Figure 1: The Iberian Peninsula with records of Triturus marmoratus (solid round symbols) and T. pygmaeus (open round symbols). A – Localities sampled for the evaluation of SNP-marker diagnosticity. For details see Supplementary Information S1. The boxed area includes the Lisbon Peninsula and the Caldas da Rainha area. B – Localities sampled in the Lisbon Peninsula, with symbols as above. For details see Supplementary Information S2. The continuous distribution with T. marmoratus in dark grey and T. pygmaeus in light grey is from Arntzen et al. (2009) and Arntzen (2018). Note the existence of a T. marmoratus enclave around Caldas da Rainha. Localities codes are C for Caldas da Rainha, L for Lisbon and S for the Serra de Sintra.
Figure 2: Two-species distribution models for the newtsTriturus marmoratus and T. pygmaeus over the Iberian Peninsula, derived from the climatic variable ‘precipitation of driest quarter’. A – present day. The colour legend shows the inferred probability for the presence of T. marmoratus (blue) and T. pygmaeus (Pm=0, red). Intermediate colours represent intermediate probabilities. The light shaded area falls outside theTriturus range (see Figure 1). B – distribution models over the western part of the Iberian Peninsula for the climate conditions of the Mid Holocene. Inferred species ranges are shown in grey (Pm>0.5) and in white (Pm<0.5). Model representation is binary and cumulative, so that the stepped grey scale represents the number of models supporting the presence of T. marmoratus , from zero to nine. C – as in B, for three climate reconstructions at the Last Glacial Maximum. Note that most models support the contiguous species border to be more or less stable, whereas one model supports a more southern species border during the Late Glacial Maximum.