Memoranda Soc. Fauna Flora Fennica 89: 25–31. 2013 25 Pool frog (Pelophylax lessonae) CAMERANO 1882 (Anura, Ranidae), an addition to the Finnish amphibian fauna Tom Hoogesteger, Joel Rahkonen & Ari Karhilahti Hoogesteger, T., Department of Biological and Environmental Science, FI-40014 University of Jyväskylä, Finland. E-mail:
[email protected] Rahkonen, J., Department of Biological and Environmental Science, FI-40014 University of Jyväskylä, Finland. E-mail:
[email protected] Karhilahti, A., Zoological Museum, FI-20014 University of Turku, Finland. E-mail:
[email protected] A population of pool frogs (Pelophylax lessonae) has been discovered in the municipality of Kaari- na, southwestern Finland. The species had not previously been recorded from Finland. The frogs show the external characteristics of the northern clade of the species, which suggests that they are of different origin than the allochthonous edible frogs (Pelophylax kl. esculentus) that are also present in southwestern Finland. Introduction is the case in Denmark and southernmost Swe- den, where P. kl. esculentus is common but nei- In the northern and central parts of Europe, the ther of the parental species is present (Gasc et al. green frog complex consists of two species: the 1997, Fog et al. 2001, Christiansen et al. 2005). marsh frog (Pelophylax ridibundus) and the pool Ridibundus – esculentus -systems, in which P. frog (P. lessonae), as well as the hybrid between kl. esculentus reproduces with P. ridibundus, are these two species, the edible frog (P. kl. esculen- known from Germany, the Baltic coast of Poland tus). The hybrids reproduce by means of hybri- and the island of Bornholm, Denmark (Rybacki dogenesis, in which one parental genome is com- & Fog 1995, Fog et al.