Various bat species are expanding their ranges due to changes in climate and landscape. These range expansions should be monitored thoroughly because they may alter local bat communities. The steppe whiskered bat Myotis davidii, for instance, has probably expanded its range from Central Asia to Eastern Europe. However, monitoring the range expansion of M. davidii is challenging because M. davidii and its sister species M. mystacinus are morphologically similar. Here, we investigated whether M. davidii occurs in Austria, which would extend its known range to the North-West. To facilitate the morphological identification of M. davidii and enable efficient monitoring approaches, we propose a morphometric approach. We analysed morphometric data of 102 M. mystacinus and 78 M. davidii. We applied sex-specific linear discriminant analyses to investigate whether a combination of hindfoot length, tibia length and forearm length could be used to distinguish M. davidii from M. mystacinus. The discriminant functions correctly identified 88% of females and 82% of males of the genetically verified individuals. Combined with dental characteristics, bat workers can reliably identify M. davidii based on morphometric traits. To investigate whether M. davidii had been previously found in Austria, we applied the discriminant functions to data of 61 Austrian M. mystacinus specimens preserved in the Natural History Museum Vienna. Since we did not find M. davidii specimens in the museum’s collection – the most comprehensive of Austrian mammal collection – we presume that M. davidii is a relatively new element of the Austrian fauna. This indicates that M. davidii has expanded its range over the last decades. The discriminant functions will facilitate monitoring of this potential range expansion.