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This paper presents new findings on abnormal specimens of amphibians in the Volga basin. Some anomalies have been noted for the first time: macrophthalmia, eardrum anomalies in marsh frogs (P. ridibundus), the absence of a tympanic membrane in green toads and ectromelia in spadefoot Pallas samples (P. vespertinus).
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Fayzulin et al. (2018) studied this question.
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