Myotis ater is known from a number of locations over a wide range from Southeast Asia to the Moluccas. The species, however, is difficult to identify externally, and some former records are no longer valid, while others need to be checked. Limits of the species’ distribution would greatly benefit from genetic work and the development of echolocation keys for Myotis in the region.
M. ater is easily confused with M. muricola, and has at times been considered to be part of it (Koopman and Gordon 1992; Koopman 1993), but is treated here as distinct following Simmons (2005). Francis and Hill (1998) reviewed specimens from Borneo and Peninsular Malaysia and determined that the two likely occur sympatrically in Borneo, Peninsular Malaysia, and Sulawesi. However, they did not make direct comparisons with material from Sulawesi, and they expressed some reservations about the identity of M. ater in Peninsular Malaysia (Francis and Hill 1998).
The only confirmed site for Borneo appears to be Mount Kinabalu and records elsewhere reported in Hill and Francis (1984) and Payne et al. (1985) are either M. muricola or M. gomantongensis (Francis and Hill 1998). For this reason we conservatively map only this site on the island despite the fact that the species might actually be common throughout the island like M. muricola (Francis and Hill 1998), and because M. ater has not been recorded in recent surveys (Struebig et al. 2006; Suyanto and Struebig 2007). We map the species on Sulawesi, and elsewhere in the Wallacea (e.g., Ambon, Halmahera, Buru, and Seram) (Corbet and Hill 1992; Flannery 1995). Reports of the species inhabiting Papua New Guinea and Australia represent either M. moluccarum or M. adversus (Cooper et al. 2001).
The species is often said to occur in Sumatra, but there is no reliable information for it on this island. We map M. ater in Siberut off Sumatra, following Corbet and Hill (1992) pending further investigation.
Specimens previously reported to M. muricola from Culion Island, near Palawan and Camarines, Luzon, Philippines are M. ater. Another bat collected in Bukidnon, Mindanao, Philippines might also represent M. ater (Heaney et al. 2005).
Subsequent records from Peninsular Malaysia confirm its presence (Kingston et al. 2003). There are no records of M. ater from Singapore (Pottie et al. 2005; Lane et al. 2006), but it is thought to have historically occurred here, based on its distribution in Borneo and Peninsular Malaysia (Lane et al. 2006).
The northernmost records of the species are from Viet Nam (Bates et al. 1999; Hendrichsen et al. 2001). A series of surveys of protected areas from 1997-2000 found M. ater in four of six of areas; the two where it was not found were the two sites that were surveyed most quickly (i.e., Huu Lien N.R. and Kon Cha Rang N.R.; Hendrichsen et al. 2001).
The only genetic study of M. ater in relation to other members of its genus used material from Huai Kha Khang Wildlife Sanctuary, Thailand (Bickham et al. 1986). More work is needed to determine the extent of its occurrence in that country (for an overview of bat species distribution in Thailand see, Bumrungsri et al. 2006). Oddly, there have been several subsequent genetic studies of Myotis in the region, but none include M. ater (e.g., Ruedi and Mayer 2001; Bickham et al. 2004).
With the species occurring in Viet Nam and Thailand it would not be surprising if it also was found in intervening Lao PDR. Although the species has not been recorded from here, Francis et al. (1999) report one specimen that could be M. ater.