Pipistrellus pygmaeus (*)
Pipistrellus (Pipistrellus) pygmaeus Leach, 1825
Type locality: England, Devonshire, Dartmoor.
* Pipistrellus (Pipistrellus) mediterraneus Cabrera, 1904
* Leach, 1825. Zool. J., 1: 559.
* British Isles, Scandinavia south to Spain, Portugal, Corsica, Sardinina, Italy, Slovenia, and Greece
The Soprano Pipistrelle (Pipistrellus pygmaeus) is a small bat that was only formally separated from the Common Pipistrelle Pipistrellus pipistrellus in 1999.
The two species were first distinguished on the basis of their different-frequency echo-location calls. The Common Pipistrelle uses a call of 45 kHz, while the Soprano Pipistrelle echo-locates at 55 kHz. The two species are sometimes called the 45 kHz pipistrelle and the 55 kHz pipistrelle, or the bandit pipistrelle (common) and the brown pipistrelle (soprano). Since the two species were split, a number of other differences, in appearance, habitat and food, have also been discovered.
The frequencies used by this bat species for echolocation lie between 53-86 kHz, have most energy at 55 kHz and have an average duration of 5.8 ms. 
1. ^ Parsons, S. and Jones, G. (2000) 'Acoustic identification of twelve species of echolocating bat by discriminant function analysis and artificial neural networks.' J Exp Biol., 203: 2641-2656.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License