Li MA,Jianchi PEI,Cuntong ZHOU,et al.Sexual Dimorphism, Female Reproductive Characteristics and Egg Incubation in an Oviparous Forest Skink (Sphenomorphus incognitus) from South China[J].Asian Herpetological Research(AHR),2018,9(2):119-128.[doi:10.16373/j.cnki.ahr.180011]
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Sexual Dimorphism, Female Reproductive Characteristics and Egg Incubation in an Oviparous Forest Skink (Sphenomorphus incognitus) from South China
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Asian Herpetological Research[ISSN:2095-0357/CN:51-1735/Q]

2018 VoI.9 No.2
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Sexual Dimorphism, Female Reproductive Characteristics and Egg Incubation in an Oviparous Forest Skink (Sphenomorphus incognitus) from South China
Li MA12 Jianchi PEI2 Cuntong ZHOU23 Yu DU24 Xiang JI2 and Wen SHEN1*
1 School of Sports and Health, Hangzhou Normal University, Hangzhou 310036, Zhejiang, China
2 Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, Jiangsu, China
3 College of Ecology, Lishui University, Lishui 323000, Zhejiang, China
4 Hainan Key Lab for Herpetology, College of Tropical Biology and Agronomy, Hainan Tropical Ocean University, Sanya 572022, China
egg hatchling morphology incubation length reproduction Scincidae sexual dimorphism
We studied sexual dimorphism and female reproduction in an oviparous forest skink (Sphenomorphus incognitus) from South China. We incubated eggs under five thermal regimes (22, 25, 28, 25 ± 3 and 27 ± 5 °C) to examine the effects of constant versus fluctuating temperatures on incubation length and hatchling morphology. In our sample the largest male and female were 110 mm and 108 mm snout-vent length (SVL), respectively. Adult males and females did not differ in mean SVL; adult males were larger in head size (both length and width), longer in fore- and hind-limb lengths and shorter in abdomen length than females of the same SVL. Accordingly, we conclude that S. incognitus is a sexually monomorphic species in terms of SVL but shows sexual dimorphism in head size, abdomen length and appendage length. Females laid a single clutch of 3?10 eggs per breeding season from early May to mid-August, with larger females generally laying more (but not always larger) eggs per clutch than did smaller ones. Embryonic stages at laying ranged from Dufaure and Hubert’s (1961) stage 31 to 32, with a mean stage of 31.3. The positive relationship between clutch mass and female SVL was not significant. The offspring size-number trade-off does not exist in S. incognitus, as revealed by the fact that egg mass was independent of relative fecundity. Incubation length decreased as temperature increased, and stable temperatures resulted in delayed hatching. Hatchlings incubated under the five thermal regimes did not differ from each other in any examined trait, suggesting that S. incognitus is among oviparous reptilian species where incubation temperature has no role in modifying hatchling morphology as long as eggs are not exposed to extreme temperatures for prolonged periods of time.


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Last Update: 2018-06-26