摘要We collected 75 adult Tonkin forest skinks(Sphenomorphus tonkinensis)from Hainan,South China and incubated eggs at four constant temperatures ranging from 22℃ to 28℃ to study sexual dimorphism,female reproductive characteristics and embryonic thermosensitivity.The largest male was 53.4 mm snout-vent length(SVL),and the largest female was 54.3 mm SVL.The mean SVL was slightly greater in adult females(49.9 mm)than in adult males(48.8 mm),but the difference was not significant.Head length,head width,fore-limb length and hind-limb length were longer in adult males and abdomen length was longer in adult females after accounting for SVL.Accordingly,we conclude that S.tonkinensisis basically a sexually size-monomorphic species with sexual dimorphism in head size,abdomen(trunk)length and limb size.Females laid up to two clutches of 1-4 eggs each per egg-laying season from February to May.Egg mass,clutch size and clutch mass were independent of female SVL.Embryonic stages at laying varied from Dufaure and Hubert's stage 30 to 31.With female SVL held constant,the negative correlation between egg mass and clutch size was not significant,suggesting that the offspring(egg)size-number trade-off between is not evident or eggs are well optimized for size in S.tonkinensis.None of the eggs at 28℃ hatched;hatching success was lower at 22℃ than at 24℃ or 26℃.The mean incubation length was 52.9 d at 22℃,40.4 d at 24℃ and 33.6 d at 26℃.Hatchlings from eggs incubated at 22℃,24℃ and 26℃ did not differ morphologically at hatching,suggesting that temperatures within this range do not differentially affect hatchling morphology in S.tonkinensis.