北京地区中华姬鼠与大林姬鼠的数量分类研究

Quantitative Classification of Mice A.draco and A.peninsulae from Beijing

利用主成分分析、系统聚类分析和非参数检验,对采自北京地区的88只姬鼠标本(黑线姬鼠Apodemus agrarius除外)的10个形态分类指标进行了分析,以便确定出最具种间特异性的形态分类特征并给出定量判别标准.结果表明:除黑线姬鼠外,北京地区另有中华姬鼠(A.draco)和大林姬鼠(A.peninsulae)两种姬鼠;门齿孔后缘距上臼齿列前缘水平线的距离(x_9)、上颌M^1后内侧齿突向舌侧突出的程度(x_1)及其与第2横嵴内侧齿突的相对大小(x_2)是区分后两种姬鼠的最有效的形态分类指标;3个指标的种间界限大致为:中华姬鼠x_9<0.4mm, x_1≥0.2mm,x_2≥0.6;大林姬鼠x_9≥0.4mm,x_1<0.2mm,x_2<0.6.

In this paper we tried to settle two problems： （1）Does Apodemus draco exist in Beijing areas, besides A. agrarius and A. peninsulae？ （2）What are the significant morphological differences between A. draco and A. peninsulae from Beijing？ Ten characteristics of skull, teeth and appearance of the 88 specimens of Apodemus collected from Beijing except A. agrarius were analyzed by principal component analysis, cluster analysis and nonparametric test for two independent samples. The results indicated that there is Apodemus draco in Beijing and the chief distinguishing characteristics between A. draco and A. peninsulae lay in： the distance between the posterior margin of the incisive foramina and the level of the anterior edge of the first molar （x9） ; the width of postero-internal lobe on the first upper molar （x1） and its ratio to that of the cusp in front of it （x2）. These quantitative characteristics differed significantly and overlapped very little between A. draco and A. peninsulae. The two species could be successfully identified depending upon the following standards： x9 〈 0.4mm, x1 ≥ 0.2mm and x2 ≥ 0.6 for A. draco, while x9 ≥ 0.4mm, x1 〈 0.2mm and x2 〈 0.6 for A. peninsulae.