Christmas Island pipistrelle
It was a small bat (it weighed ), and lived only on Christmas Island, Australia.van Dyck S. & Strahan R. (eds) 2008. The mammals of Australia. It was thought to be the same as the Pipistrellus tenuis,Koopman K.F. 1993. Order Chiroptera. 137-241 in: Wilson D.E. & Reeder D.M. (eds) Mammal species of the world: a taxonomic and geographic reference. Smithsonian Institution Press, Washington D.C. but research on the bat's baculum (a penis bone) showed that Pipistrellus murrayi'' was a different species.