New data on distribution of amphibians and reptiles in the Aral Sea Basin and surrounding areas of Kazakhstan. Part I. The Green Toads of Bufo viridis complex (Amphibia: Anura)

First the data on distribution of the toads of Bufo viridis complex are presented for Aral Sea Basin and surrounding areas of Southern and Western Kazakhstan. Karyological analysis revealed a presence of diploid toad populations in the valley of the middle and low flows of Syr-Darya River; in the northern coast of Aral Sea and the desert areas between the last and Irgyz-Turgay Basin; in the northern part of Karatau Range. The only tetraploid population was discovered in the central part of Karatau Range. Introduction From a time of first record of tetraploid green toad population in the mountains of Kirgizyia (Masik et al., 1976) and a first description of a tetraploid species Bufo danatensis Pisanets, 1978 (Pisanets, 1978) the toads of Bufo viridis complex continue to be one of the most problematical and curious taxonomic groups of amphibians. For near of quarter of century a huge number of data on distribution of diploid, triploid and tetraploid populations were collected, a series of new taxa were described and some ideas on origin and evolution of tetraploid toads were proposed. Recently Stöck et al. (2001a) has undertaken a deep taxonomic revision of the Asian Bufo viridis group comprising 23 nominal taxa. He presented data on type localities, nomenclatural and systematic histories, karyotypes and distribution; proposed current taxonomic status and tentative identification key as well as indicate the regions lack available data on B. viridis complex (Stöck et al., 2001a: Fig. 16). To present time the green toad populations with identified karyotypes are know from Iran, Tadjikistan, Turkmenistan, Uzbekistan, Kirgyzstan, Kazakhstan, Afganistan, Pakistan, Turkey, India, Mongolia and China (See literature references in Stöck et al. (2001b). In spite of a number of the green toad records with ploidy detection known for southern regions of Central Asia, a vast territory of northern deserts and steppes still stayed out of study. Except of few finds, a huge area between the Caspian and Aral Seas, the deserts between Syr-Darya and Amu-Darya Rivers including the rivers valleys and the territories of Central, Northern and Eastern Kazakhstan lack distributional data on the toads of Bufo viridis complex with identified karyotype. In current paper we try to improve a deficiency of our knowledge on distribution of the green toads of Bufo viridis complex and represent the results of our investigation in Aral Sea Basin and surrounding areas of Southern and Western Kazakhstan. Material and methods Field work was carried out in May –June 2002-2003 mainly in Aral Sea Basin (Western, Northern and Northeastern Aral Sea regions including the low flow of Syr-Darya River), Mugodzhar Mountains, Irgyz-Turgay Basin and partially in the valley of the middle flow of Syr-Darya River and Karatau Range (Fig. 1). The toads were collected in the first hours of the night when the reproductive activity was maximal. Only adult specimens with well-developed secondary sexual characters were sampled for measurements. Next day after capture the toads were anaesthized in MS-222 (Sandoz), weighed and measured in 20 body-proportion characters with a digital caliper (Mitutoyo mod. 500321) calibrated to 0.01 mm. The results of morphometrical analysis will be presented elsewhere. The adult specimens from 9 localities (totally 53 specimens) were taken alive to laboratory for a karyological analysis. From each specimen 100-200 μl of venous blood were incubated for 4 days at 25°C in MEM (Minimal Eagle Medium, GIBCO) with 20% calf serum and 3% Phytohaemogglutinin M. Chromosome preparations were produced by conventional air-drying method, using KCl 0.075M as hypotonic solution. Standard staining method was performed using Giemsa 5% in phosphate buffer pH 7.