Anatomy and Histology of the Male Reproductive System southern grass skink, Heremites septemtaeniatus (Sauria: Scincidae)

In reptiles, knowledge of reproductive studies can help clarify evolutionary relationships by identifying morphological traits and has a fundamental role in advancing our understanding of animal biology, ecology, and evolution. Numerous studies have concentrated on reproductive cycles in skinks; a large percentage of skinks, such as Heremites, are known to be viviparous (45%). The genus Heremites is a member of the diverse family Scincidae with about 2039 species. Heremites septemtaeniatus is one of the species of the Heremites genus, which occurs in Iran. In this study, the histological changes of the male reproductive system were described for the viviparous lizard, H. septemtaeniatus. Six adult males were collected from March to late September around West Islamabad, Kermanshah, Iran. The specimens were anesthetized, euthanized, and dissected in the zoology laboratory according to the protocol of the Ethics Committee on Laboratory Animal Research-Razi University. Then, the male reproductive system was studied anatomically. Testes and testicular ducts were removed and fixed in 10% neutral buffered formalin, dehydrated, embedded, and sectioned at 5 μm. The prepared slides were stained with hematoxylin and eosin stain and were examined by light microscopy. The testis has a simple squamous epithelium, while the epididymal epithelium is pseudostratified columnar. Males of H. septemtaeniatus follow a seasonal testicular cycle. In H. septemtaeniatus, males appear from winter hibernation earlier in the season than females. Results showed that annual variations occurred in the diameter and height of the epithelium of seminiferous tubules and ductus epididymis; the testicles became larger in the reproductive phase (Spring) and their lumen was full of sperm. From early July to late September, the diameter and thickness of the testicular ducts decreased. There were minor annual differences in the timing of reproductive events, which we attribute to the variation in thermal conditions and the amount of precipitation.