Environmental and climatic drivers of phenotypic evolution and distribution changes in a widely distributed subfamily of subterranean mammals

How environmental factors shape species morphology and distributions is a key issue in ecology, especially in similar environments. Species of Myospalacinae exhibit widespread distribution spanning the eastern Eurasian steppe and the extreme adaptation to the subterranean environment, providing an excellent opportunity for investigating species responses to environmental changes. At the national scale, we here use geometric morphometric and distributional data to assess the environmental and climatic drivers of morphological evolution and distribution of Myospalacinae species in China. Based on phylogenetic relationships of Myospalacinae species constructed using genomic data in China, we integrate geometric morphometrics and ecological niche models to reveal the interspecific variation of skull morphology, trace the ancestral state, and assess factors influencing interspecific variation. Our approach further allows us to project future distributions of Myospalacinae species throughout China. We found that the interspecific morphology variations were mainly concentrated in the temporal ridge, premaxillary-frontal suture, premaxillary-maxillary suture, and molars, and the skull morphology of the two current species in Myospalacinae followed the ancestral state; temperature and precipitation were important environmental variables influencing skull morphology. Elevation, temperature annual range, and precipitation of warmest quarter were identified as dominant factors affecting the distribution of Myospalacinae species in China, and their suitable habitat area will decrease in the future. Collectively, environmental and climate changes have an effect on skull phenotypes of subterranean mammals, highlighting the contribution of phenotypic differentiation in similar environments in the formation of species phenotypes. Climate change will further shrink their habitats under future climate assumptions in the short-term. Our findings provide new insights into effects of environmental and climate change on the morphological evolution and distribution of species as well as a reference for biodiversity conservation and species management.