Characterization of testicular histology and spermatogenesis in the Levantine frog, Pelophylax bedriagae (Amphibia: Anura: Ranidae)

Abstract

Amphibians occupy a position of great interest in terms of vertebrate evolution. Additionally, amphibians are known as a transitional group between amniotes and anamniotes. However, there are few studies on the gametogenesis of anamniotes vertebrates, especially anurans. Therefore, the purpose of this study was to analyze the histological feature of germ cells and their arrangement in the testis of Levantine frog, Pelophylax bedriagae (Camerano, 1882). Spermatogenic cells were organized in spermatocysts. Each spermatocyst contained cells at the same stage of the spermatogenic cycle. Identification of each cellular type in seminiferous tubule was carried out according to the size and morphology of cells and the degree of nuclear material compaction. Spermatogonia were large cells localized at the base of the seminiferous epithelium. Primary spermatocytes were examined in different phases of first meiotic division and distinguished from other cell types by their dark spherical nuclei or looser chromatin. Two types of spermatids, spherical and elongated cells, were observed. Seminiferous tubules were surrounded by peritubular myoid cells, and they contained no lumen. The lack of lumen in the seminiferous tubules and the cystic spermatogenesis probably provide synchronously production of a large number of sperms. The location of hyaluronic acid was also determined in interstitial tissue between seminiferous tubules to probably provide testicular integrity and viscoelasticity.