Taxa involving three bisexually reproducing ploidy levels make green toads a unique amphibian system. We put a cytogenetic dataset from Central Asia in a molecular framework and apply phylogenetic and demographic methods to data from the entire Palearctic range. We study the mitochondrial relationships of diploids to infer their phylogeography and the maternal ancestry of polyploids. Control regions (and tRNAs between ND1 and ND2 in representatives) characterize a deeply branched assemblage of twelve haplotype groups, diverged since the Lower Miocene. Polyploidy has evolved several times: Central Asian tetraploids (B. oblongus, B. pewzowi) have at least two maternal origins. Intriguingly, the mitochondrial ancestor of morphologically distinctive, sexually reproducing triploid taxa (B. pseudoraddei) from Karakoram and Hindukush represents a different lineage. We report another potential case of bisexual triploid toads (B. zugmayeri). Identical d-loops in diploids and tetraploids from Iran and Turkmenistan, which differ in morphology, karyotypes and calls, suggest multiple origins and retained polymorphism and/or hybridization. A similar system involves diploids, triploids and tetraploids from Kyrgyzstan and Kazakhstan where green toads exemplify vertebrate genomic plasticity. A new form from Sicily and its African sister species (B. boulengeri) allow internal calibration and divergence time estimates for major clades. The subgroup may have originated in Eurasia rather than Africa since the earliest diverged lineages (B. latastii, B. surdus) and earliest fossils occur in Asia. We delineate ranges, contact and hybrid zones. Phylogeography, including one of the first non-avian datasets from Central Asian high mountains, reflects Quaternary climate and glaciation.

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M'e describe the spatial pattern of variation of morphometric characters and call acoustic properties of tetraploid green toads (Bufo vzdk complex) from eight populations in Central Asia, and we analyse the causal agents responsible for the patterns observed, by means of partial Mantel tests. Populations siLgnificantly differ with respect to both body size and body shape. Since animals inhabiting the driest regions are smaller, but not younger, than animals from less dry areas, we suggest that their small body size is due to the limiting effect of arid climate on growth rate. Differences in body shape are positively associated only with geogaphic distances, and we suggest that isolation by distance might have played an important role in determining the pattern of variation. Populations significantly differ also with respect to the acoustic properties of the call, in particular, with respect to temperatureadjusted pulse rate and body size-adjusted fundamental frequency; that is, with respect to those properties which are under the strongest morphological or physiological constraints, and that show the lowest variability within individuals (static properties). The pattern of variation of calls shows positive association with geographic distances, but not with climatic distances. Calls do vary, and in this region the main causal agent responsible for call variation might have been the isolation by distance. The evolutionary implications of these results are discussed.

In the present paper we compare, on the basis of morphometrical characters and acoustical properties of the advertisement calls, a sample of 158 male green toads (Bufo vidzi complex) collected in 12 breeding populations of south Kazakstan and north Kyrgyzstan. The samples of three populations resulted in only diploid toads (2n = 22), those of eight populations in only tetraploid toads (2n=44) whereas in one locality diploid, tetraploid and many triploid toads were collected. Diploid toads show significantly larger body size and proportionally larger head and shorter limbs than both tetraploids and triploids, whereas no evident morphometrical differences were observed between triploids and tetraploids. Diploid advertisement calls have spectral and temporal properties that significantly differ from those of both triploid and tetraploid advertisement calls. In particular, diploids produce significantly longer calls with higher pulse-rates and lower frequencies than those of tetraploids. We address the question of the factors that could be responsible for these differences and we discuss four hypotheses: (1) the direct effect of polyploid mutation, (2) genetic drift, (3) reproductive character displacement and (4) environmental selection.

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