Katarzyna Haczkiewicz et al.
Zoology (Jena, Germany), 122, 63-79 (2017-05-14)
Spermatogenesis in frogs was for the first time divided into two phases: prespermatogenesis, when gonocytes proliferate in developing tadpole testes, and active spermatogenesis when spermatogonial stem cells (i.e. descendants of gonocytes), either self-renew or enter into meiotic cycles within cysts