For the last decade, chytridiomycosis was considered to be caused by a single species of fungus, Batrachochytrium dendrobatidis (Bd), but a second chytrid species, Batrachochytrium salamandrivorans (Bs), was recently isolated from an infected Salamandra salamandra in the Netherlands. To date, Bs has only been found in the Netherlands. To assess whether Bs is present in China, we analyzed a total of 665 samples, including 425 wild samples, 41 preserved specimens, and 199 captive samples, from 30 different species, including both urodeles and anurans. Our sample sites covered 15 provinces in China. All of the samples tested negative for Bs, resulting in a 95% confidence limit for a prevalence of 0.6%. The absence of Bs observed in this large-scale survey in China has significant implications for amphibian conservation and for border trade management strategies intended to control amphibian diseases. We strongly recommend the continued close monitoring of Bs to verify the status of this potentially devastating amphibian fungus in China.

In order to study the diversity, phylogenetic relationships and distribution of marsh frogs of the Pelophylax ridibundus complex in Kazakhstan and northwest China, we conducted phylogeographic analyses of 125 samples from 53 localities using the mtDNA ND2 and COI genes and the SAI nuclear gene sequences. Phylogenetic inference of mtDNA revealed three main lineages—sister lineages Balkhash and Syrdarya (as the Central Asian P. sp. novum), and the Anatolian P. cf. bedriagae, while from nDNA data, we additionally detected the western form, P. ridibundus. According to mtDNA data, the mean genetic distances between P. sp. novum and two other forms of marsh frogs was more than 5%. Genetic homogeneity within populations of the Syrdarya lineage and P. cf. bedriagae is characterized by low nucleotide diversity and high haplotype diversity. Demographic analyses of the lineages showed past population expansions of the Balkhash and the Syrdarya forms. Divergence from the most recent ancestor had occurred in the Early Pleistocene period (2.46 Mya) for the Balkhash and the Syrdarya lineages, and 1.27 Mya for the P. cf. bedriagae. Our findings provide a first investigation of the lineage diversification and population dynamics of the Central Asian marsh frogs and will be useful for further taxonomic implications and conservational actions.