POSTHATCHING DEVELOPMENT OF THE REPRODUCTIVE ANATOMY IN MALE EASTERN FENCE LIZARD (SCELOPORUS UNDULATUS)
Recent observations from our lab suggest that the timing of fundamental events in the development of male lizard reproductive anatomy differs from mammals and birds. Masculinization of the embryonic urogenital tract occurs during embryonic development in mammals and birds but has not been thoroughly examined in reptiles. In this study we described the post-hatching development and maturation of the reproductive system in male Eastern Fence Lizards. Male lizards ranging from neonates to small adults were captured monthly by hand or with a noose pole in the Oconee National Forest, GA, USA over a span of two years. Testes and spermatic ducts were photographed at 1–5X magnification to obtain standardized morphological measures. The left testis and left reproductive tract were removed, sectioned, and stained with Masson’s trichrome to study the microanatomical changes associated with maturation. In small hatchlings, the mesonephric kidney and its associated duct are still present, as they have not yet differentiated to the epididymis and ductus deferens. The mesonephros gradually condenses anteriorly as the mesonephric tubules give rise to efferent ducts and the mesonephric duct differentiates to epididymal duct and ductus deferens. The seminiferous tubules of recently hatched lizards are populated by spermatogonia and Sertoli cells, with no distinct lumen. A positive relationship exists between testis size and spermatogenic stage in larger animals; however, testis size and spermatogenic activity were also affected by time of year. Male lizards approaching maturity show evidence of active spermatogenesis and secretions from the sexual segment of the kidney. Our results indicate masculinization of the urogenital tract in Eastern Fence Lizards occurs after hatching, and maturation of the reproductive system is influenced by the combination of size and season.
Georgia College Dept. of Biological & Environmental Sciences
Holder, Sarah; Riecke, Christina; and Milnes, Matthew R.
"POSTHATCHING DEVELOPMENT OF THE REPRODUCTIVE ANATOMY IN MALE EASTERN FENCE LIZARD (SCELOPORUS UNDULATUS),"
Georgia Journal of Science, Vol. 81, No. 1, Article 19.
Available at: https://digitalcommons.gaacademy.org/gjs/vol81/iss1/19