Quaternary range-shifts of arboreal rodents of the genus Habromys (Cricetidae, Neotominae) in Mesoamerica and their evolutionary consequences

Abstract

Arboreal mice of the genus Habromys (Cricetidae, Neotominae) comprise a clade of seven monotypic and endangered species that inhabit Mesoamerican cloud forests, one of the most threatened of the world’s ecosystems. Previous genetic analyses have suggested that closely related lineages are poorly differentiated, which is probably an evolutionary consequence of distributional shifts driven by Quaternary climate oscillations through a complex topography. Here, we assess the potential role of distributional shifts through time on current patterns of genetic differentiation in Habromys. Following recent best-practices recommendations for estimating ecological niches and paleodistributions for montane species, we estimated the potential distribution of the genus across the last glacial-interglacial cycle under three alternative Global Circulation Models to explore the more recent evolutionary history of this genus. Distributional shifts and population connectivity among populations of Habromys were greatly affected by past climate change coupled with topographic habitat heterogeneity. The effectiveness of some barriers to dispersal has changed over time as result of the climatic oscillations. Poorly differentiated genetic lineages might be an evolutionary consequence of intermittent connections and corridors for montane species motivated by glaciations. Some valleys and lowland habitats probably served as previously unrecognized barriers to dispersal during warmer periods. This study emphasizes the dynamic nature of species’ geographic distributions and potential barriers to create current patterns of genetic variation in Mesoamerican rodents.