Lutra 53(2)_Dekeukeleire_2010

First record of soprano pipistrelle (Pipistrellus pygmaeus Leach, 1825; Chiroptera: Vespertilionidae) in Wallonia (Belgium)

The soprano pipistrelle, Pipistrellus pygmaeus, is a cryptic species that highly resembles the common pipistrelle, Pipistrellus pipistrellus (Barrett et al. 1997). Jones & Parijs (1993) show that standard measurements of the animal itself are of little use for distinguishing between both; the soprano pipistrelle is generally smaller than the common pipistrelle, but the overlap is too large to allow an unambiguous identification. Although the most useful method for determining the two species remains genetic analysis and the analysis of echolocation calls (Mayer & Helversen 2001), several authors mention reliable morphological characteristics to discriminate between the two species. The most important of these are the internarial ridge, the penial morphology and the wing membrane cell pattern (Häusler et al. 2000, Ziegler et al. 2001, Sendor et al. 2002, Dietz et al. 2007). The soprano pipistrelle has a wide geographical distribution in Europe (Mayer & Helversen 2001). It lives in sympatry with its sibling species, the common pipistrelle, over most of its range. From Belgium there are only a few records of soprano pipistrelle, all of which are based on echolocation sound analyses (Kapfer et al. 2007). All observations come from Flanders (Provinces of West-Vlaanderen, Antwerp and Limburg) and Brussels, and they were mainly made in spring. In recent years, the species has been recorded annually in Brussels (Herr 2010). On the 6th of August, 2009, between 9 pm and 2 am, bats were captured with mist nets at the northern entrance of an old railway tunnel (50°04’51” N 4°34’22” E) in Viroinval (Namur, Belgium)....