The southern snow skink, Niveoscincus microlepidotus, exhibits an unusual biennial reproductive cycle with an extended gestation period of approximately 1 year. Morphological data were gathered on a monthly basis, providing a detailed picture of the reproductive cycle. Vitellogenesis begins in spring, immediately after parturition. Maximum follicular diameter is reached before the winter hibernation period and ovulation occurs the following spring. Embryos are fully developed and reach maximum size by early autumn. Yolk reserves are depleted before winter. Birth of between one and four young occurs the following spring. Plasma progesterone concentrations are low (2.7 ± 0.9 ng mL^–1) in post-partum females, begin to rise in autumn in vitellogenic females and peak (38.5 ± 7.9 ng mL^–1) in pre-ovulatory females after hibernation. Concentrations are high (15.4 ± 5.9 ng mL^–1) in early pregnancy and decline to basal levels before winter and well before birth in spring. Plasma oestradiol concentrations peak during vitellogenesis (1.0 ± 0.3 ng mL^–1) and decline to basal levels during pregnancy (0.2 ± 0.03 ng mL^–1). A second oestradiol peak occurs before parturition (0.7 ± 0.2 ng mL^–1). Thus, functional completion of vitellogenesis and gestation is achieved by autumn in successive years. The mechanisms that defer ovulation and parturition by a further six months are unknown.

Item Type:	Refereed Article
Research Division:	Biological Sciences
Research Group:	Zoology
Research Field:	Comparative physiology
Objective Division:	Environmental Management
Objective Group:	Terrestrial systems and management
Objective Field:	Terrestrial biodiversity
UTAS Author:	Girling, JE (Dr Jane Girling)
UTAS Author:	Jones, SM (Professor Susan Jones)
UTAS Author:	Swain, R (Dr Roy Swain)
ID Code:	24582
Year Published:	2002
Web of Science® Times Cited:	24
Deposited By:	Zoology
Deposited On:	2002-08-01
Last Modified:	2014-04-17
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