关键词: 高原鼢鼠, 地理种群, 形态变异, 主成分分析, 聚类分析

Abstract: The variation of seventeen morphological traits for plateau zokor (Myospalax baileyi) collected from twelve geographical populations was analyzed based on principal component analysis and cluster analysis. The results of principal component analysis showed that the cumulative contributive proportions of the first three principal components for males and first four components for females were 78.483% and 79.587% respectively. The skull characteristics included profile length, basal length,and occipital width and otherwise,coupled with the least distance between the parietal ridges and the least distance between the frontal ridges representing the extent of zygomatic expanding might become the most contributive factors for the morphological variation among populations. The results of principal component analysis and cluster analysis congruously revealed that the populations were divided into two large regional groups:the Gansu group and the mixed group including
Qinghai and Sichuan populations. These results actually reflected two different directions of evolution:one showed a lesser skull,divided parietal ridges and frontal ridges,such as Gansu group;another showed a larger skull,closed parietal ridges and frontal ridges,such as the mixed group.  This morphological variation of regional groups may result from the selection of environmental factors in the subterranean burrow system.

Key words: Cluster analysis, Geographical population, Morphological variation, Plateau zokor (Myospalax baileyi), Principal component analysis