REPRODUCTIVE CYCLE OF A HIGH-ELEVATION, OVIPAROUS LIZARD (SCELOPORUS SPINOSUS: REPTILIA: PHRYNOSOMATIDAE)

摘要

We studied the reproductive cycle of Sceloporus spinosus from Laguna La Preciosa, Puebla, Mexico, elevation 2,400 m. There was no sexual dimorphism in snout-vent length (males, 87.5 mm; females, 88.8 mm). Gonadal mass varied monthly and was related tosnout-vent length; both sexes had a synchronous reproductive cycle that peaked in late winter and early spring. In males, recrudescence occurred November-January with abundant primary and secondary spermatocytes. Maximum testicular mass was in Februarywhen seminiferous tubules showed spermiogenesis and spermatozoa were in the lumen and epididymis. Regression was evident in April, when testicular mass decreased, and it continued in May, although spermatozoa were in seminiferous tubules and lumen of epididymal ducts. In July-September, testicular mass was less, and only spermatogonias, Sertoli cells, and remains of sperm were in seminiferous tubules. In females, vitellogenesis be gan in late autumn, maximum deposition of yolk was in March, and ovulation was in April. Oviductal eggs were present in April-June and oviposition was in June^July. In August-September, only previtellogenic and atretic follicles were present; hatchlings were present in September. Size of clutch was 6-17 eggs and correlated with snout-vent length. One clutch is produced per reproductive season. Reproductive activity in both sexes was distinct from spring-summer activity in tropical sceloporines from high elevations, but was similar to other lizards in northern temperate areas.