Seasonal Dynamics of Reproductive Organs in Male Salamanders of the Species Hynobius nigrescens

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Why is it important?

Monthly changes in histological condition of the testes and sex accessory structures are reported for the first time in hynobiid salamanders with external fertilization. Spermatogenic wave that is reported in internally-fertilizing salamanders is not discernible in the testes throughout the year. By contrast, spermatogenic progress is synchronized in all the testicular lobules. Unlike internally-fertilizing salamanders, spermiation does not occur in fall and winter months, thereby inducing the absence of spermatozoa in the vasa deferentia prior to spring breeding.