Fig. 2: Sino-Himalayan Mountains and distribution ranges of the two mountainous species studied.

a The distribution ranges of P. monticolus and T. elliotii cover the Sino-Himalayan Mountains and mid-elevational mountains in Central China. The southern Tibetan zone (STZ) is in the southeastern part of the Qinghai-Tibetan Plateau, which has an average elevation of 4500 m a.s.l. This zone is dominated by shrubland (i). The southwest mountainous zone (SMZ) has a vertical climatic zonation along an elevation gradient, ranging from the temperate coniferous forest (ii), mixed forests (iii) and subtropical broadleaf forest (iv). The eastern Himalayan zone (EHZ) is on the southern margin of the Qinghai-Tibetan Plateau and encompasses a broad range of ecological habitats varying from grassy meadows to a dense humid evergreen forest (i-iii). The western mountainous plateau zone (WMPZ) is on the east side of the Sino-Himalayan Mountains and is characterised by temperate broadleaf forests (iii). b Left, the distribution ranges of P. monticolus (yellow shade) and T. elliotii (blue shade) partially overlap in the southwest mountainous zone and western mountainous plateau zone, as well as in parts of the Loess Plateau zone and east meadow zone. In the non-overlapping parts of their distributions, T. elliotii occurs in the southern Tibetan zone, and P. monticolus lives in the eastern Himalayan zone. The yellow and blue dots show the sampling localities of P. monticolus and T. elliotii used in the genomic analysis. Right, upper, T. elliotii; middle, P. monticulus; bottom, distribution ranges of the T. elliotii and P. monticulus are shown by the blue and yellow outlines, respectively, while the areas where they overlap are shown by the black outline.