Ivanov G. A. RussiaSaratovSaratov State University, 33 Astrakhanskaya Str., Saratov 410012, Russiaecoton@rambler.ru Author's articles LONG-TERM DYNAMICS OF THE SIZE-WEIGHT AND SEXUAL STRUCTURE IN POPULATIONS OF PELOBATES FUSCUS (ANURA, PELOBATIDAE) IN THE MEDVEDITSA RIVER VALLEY (SARATOV REGION)