浙江九龙山发现北仑姬蛙新种群的两性异形

Sexual Dimorphism of Beilun Pygmy Frog(Microhyla beilunensis)from Jiulongshan Mountain,Zhejiang

2017年和2018年的4月在浙江九龙山国家级自然保护区发现一种姬蛙,经形态学比较、16S rRNA序列比对及系统发育分析,鉴定为北仑姬蛙(Microhyla beilunensis),是该种的地理新分布。通过测量31只成体(25雌和6雄)的体长、头长、头宽、吻长、鼻间距、眼间距、眼径、前臂及手长、后肢全长和足长10个形态指标,研究该种的两性异形。结果显示,该种具有雌性大于雄性的个体大小两性异形;体长之外的9个局部形态特征均与体长成正相关,去除体长效应后,北仑姬蛙雄蛙前臂及手长显著大于雌蛙,其余形态特征在两性间均无差异;主成分分析(特征值≥1)显示,头长、头宽、吻长、鼻间距、眼间距、眼径、前臂及手长、后肢全长和足长等9个特定体长的形态变量辨析出两个主成分,共解释了原始数据52.5%的变异,头宽和前臂及手长在第一向量上具有较高的正负载系数,且两性形态在第一向量上差异显著,这表明头宽和前臂及手长可用于区分雌雄个体。

Amphibian resources are abundant and unique in China,and more new amphibian species were found through molecular techniques.A Microhyla species was found during a field survey in Zhejiang Jiulongshan National Nature Reserve in April of 2017 and 2018.They were identified based on morphological comparison,BLAST comparison and phylogenetic analysis of mitochondrial 16 S rRNA gene.Thirty-one adult(25♂♂and 6♀♀)were captured and measured for snout-vent length(SVL),head length(HL),head width(HW),snout length(SL),internasal distance(IND),internorbital distance(IOD),diameter of eye(DE),length of lower arm and hand(LLAH),total length of leg(TLL)and foot length(FL)to examine sexual dimorphism of this species.Corresponding data were processed by one-way ANOVA,linear regression and principal component analysis.Our results showed that:(1)the species was identified as M.beilunensis and this sample locality is a new geographic distribution of M.beilunensis(Figure 1);(2)M.beilunensis displays female-biased sexual size dimorphism(Table 3);(2)other nine morphological traits were positively related with SVL in both sexes of M.beilunensis(Figure 3);(3)the mean value of LLAH in males was larger than female after removing the effect of SVL(Table 3);(4)a principal component analysis resolved two components(eigenvalues 1)from nine SVL-adjusted morphological traits,accounting for 52.47%%of variation in the original data(Table 4).The first component had high positive loading for HW and LLAH,and morphological traits between male and female differed significantly in their scores on the first axe(Table 4),indicating that HW and LLAH could distinguish females and males.