NEW DATA ON THE DISTRIBUTION OF TWO CRYPTIC FORMS OF THE COMMON SPADEFOOT TOAD (Pelobates fuscus) IN EASTERN EUROPE L. J. Borkin, 1 S. N. Litvinchuk, 2 J. M. Rosanov, 2 M. D. Khalturin, 2 G. A. Lada, 1,3 , A. G. Borissovsky, 4 A. I. Faizulin, 5 I. M. Kotserzhinskaya, 1,6 R. V. Novitsky, 7 and A. B. Ruchin 8 Submitted March 17, 2003. The genome size variation in almost four hundred specimens of Pelobates fuscus fuscus, collected from 61 localities in Russia, Latvia, Belarus, Ukraine, Moldavia, and Kazakhstan, was studied by DNA flow cyto- metry. The existence of two geographic groups differed by genome size was confirmed by allozyme analy- sis. The distribution of the western type (with smaller genome size) and the eastern type (with larger ge- nome size) P. f. fuscus is described. Keywords: Amphibia, Anura, Pelobatidae, Pelobates fuscus, distribution, cryptic speciation, genome size, allozymes. INTRODUCTION The common spadefoot toad, Pelobates fuscus (Laurenti, 1768), is a wide-ranging European anuran species, which is distributed from central France in the west to western Siberia and northwestern Ka- zakhstan in the east. Like other spadefoot toads, P. fuscus is a nocturnal animal, and it practices hidden digging mode of life. Taxonomically, the species consists of two subspecies, namely P. f. insubricus endemic to the Po valley in northern Italy, and P. f. fuscus, which occupies the remaining huge part of the species’ range. The variation in P. fuscus is poorly known (Nöllert, 1990, 1997; Borkin, 1998). In 1997, occasionally, we have found that speci- mens of P. f. fuscus from Pskov and Ryazan prov- inces (European Russia), treated at the same day, showed pronounced differences in the amount of nu- clear DNA. Later, based on many samples from vari- ous localities, we identified two distinct groups of the common spadefoot toad with different genome size. Geographically, these groups with smaller or larger genome size were found to be distributed in the west and in the east of eastern Europe, respectively (Barabanov et al., 1998; Borkin et al., 2001a, 2001b, 2003; Khalturin et al., 2003). This study concentrates on the distribution of the western type and the eastern type of P. f. fuscus based on numerous genome size data, which have been ac- cumulated since 1995. MATERIAL AND METHODS Almost four hundred specimens from 61 locali- ties in Russia (45), Ukraine (9), Belarus (2), Kazakh- 1026-2296/2003/1002-0115 © 2003 Folium Publishing Company Russian Journal of Herpetology Vol. 10, No. 2, 2003, pp. 115 – 122 1 Zoological Institute, Russian Academy of Sciences, Universitetskaya nab. 1, St. Petersburg 199034, Russia. E-mail: borkin@spas.spb.su 2 Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr., 4, St. Petersburg 194064, Russia. 3 Tambov State University, 33, ul. Internatsionalnaya, Tambov 392622, Russia. 4 Udmurt State University, 1/1, ul. Universitetskaya, Izhevsk 426034, Russia. 5 Institute of Ecology of the Volga River Basin, Russian Academy of Sciences, 75(27), ul. Dzerdzhinskogo, Toliatti 445032, Russia. 6 Shmalgauzen Institute of Zoology, National Academy of Sciences of Ukraine, 15 B. Khmeknitskogo, Kiev 01601, Ukraine. 7 Institute of Zoology, National Academy of Sciences, 27 ul. Akademicheskaja, Minsk 220072, Belarus. 8 Mordovian State University, 68, Bolshevistskaya str., Saransk 430000, Russia.