Cytological evaluation of spermatogenesis and organization of the germinal epithelium in the male slider turtle, Trachemys scripta.

The germ cell development in the slider turtle (Trachemys scripta) testis was investigated by viewing the histology of the seminiferous epithelium in plastic sections with a light microscope. Germ cell morphologies in the slider turtle testis were similar to the morphologies of other vertebrate germ cell types. However, the slider turtle seminiferous epithelium contained germ cells that progress through spermatogenesis in a temporal rather than a spatial pattern, resulting in a single spermatogenic event that climaxed with one massive sperm release in November. Mature sperm then are stored within the epididymis until breeding commences in the following spring. The germ cell development strategy in the slider turtle is different from that of other amniotes and is more reminiscent of the developmental strategy found in the anamniotic testis. This temporal progression of germ cells through spermatogenesis within a tubular testis represents a transitional model that may be evolutionarily significant.