We studied a population of E. atkinsi in eastern Cuba and describe post-reproductive variables (clutch size, eggs, embryonic development, and hatchlings) along with gonadal ultrastructure using microscopic techniques (LM and TEM). We found that most eggs had an advanced stage of embryonic development, with embryos having elongated limbs, noticeable blood vessels, nubs of digits, and in some cases expanded toe discs. In all clutches, we observed adult males or females next to the oviposition sites, suggesting biparental care during embryonic development. Snout–vent length versus oviducal eggs were highly correlated, and CT-scan images of gravid females highlight the number and disposition of the oviducal eggs below the axial skeleton and pelvic girdle. Hatchling coloration was similar to adults, but we also observed highly polymorphic color variation. We describe spermatogonia, spermatocytes I–II, spermatids, and spermatozoa. The mature sperm has an elongated head and tail with an undulating membrane, a structure used in phylogenetic reconstructions. Cross-sectional undulating membrane consists of an axoneme with an associated juxtaxonemal fiber, an axial sheath, and an axial fiber. In the ovary, oogonia are located in a peripheral germinal nest, surrounded by follicle cells. During folliculogenesis, two stages of development were observed: pre-vitellogenesis and vitellogenesis. Our results indicate that E. atkinsi displays remarkable reproductive adaptations and can be used as a model for other endemic Cuban species.