Integrative taxonomy and biogeography of Asian yellow house bats (Vespertilionidae : Scotophilus) in the Indomalayan Region

Yellow house bats (Scotophilus) have been known for centuries as a widespread genus of vesper bats in the Indomalayan Region. Despite this, their taxonomic status and phylogeographical patterns remain unclear due to differing criteria employed by early taxonomists and inconsistencies between morphological and molecular assessments. To address these issues, we undertook a comparative phylogeographic analysis of Asian Scotophilus spp. using integrated genetic and morphological analyses of samples collected across the region. These demonstrate that yellow house bats in Asia can be classified into just two widespread species, namely the smaller S. kuhlii (e.g., FA ≤ 53.1 mm, GLS ≤ 20.18 mm) and the larger S. heathii (e.g., FA ≥ 53.4 mm, GLS ≥ 20.85 mm), which occur in sympatry in different parts of the Indomalayan Region. Although these two sympatric species share similar eco-ethological preferences, they differ considerably in their geographic distributions and intraspecific variation in mtDNA sequences and morphological traits. These disparities were likely misinterpreted as indicating potential cryptic diversity in previous studies, whereas we suggest they are related to interspecific differences in sex-biased gene flow and phenotypic plasticity to adapt to varying environments. Our study highlights the importance of using multiple datasets to resolve taxonomic uncertainties and reconstruct demographic and phylogeographic histories of sympatric species.