RESULTS: Three morphological forms were confirmed within the region; two concur with previously recognized taxa, namely R.affinis macrurus andR.affinis superans,and are strongly supported by morphological and genetic data. The third form is morphologically distinct, but its taxonomic status remains unclear. It is probable that this third form represents a distinct taxonomic entity; however, more data are required to confirm this. R. a. macrurus is known from the north of peninsular Thailand, Cambodia, Myanmar, Laos, and Vietnam (Indochinese subregion); R. a. superans is found throughout the Thai-Malay Peninsula (Sundaic subregion); whilst the third form is presently known from east central Myanmar (Shan state) and lower northern Vietnam (Nghe An Province).
CONCLUSIONS: Our results suggest that at least three morphological forms occur in mainland Southeast Asia including one form which appears to be new to science. Echolocation call data for R. affinis are not a robust taxonomic tool as it shows a significant degree of variation which is not explained or supported by genetic and morphological findings. This study highlights significant levels of morphological variation in mainland Southeast Asia and provides an essential basis for further studies aiming to understand the population genetics, phylogeography, and taxonomy of the species.