基于线粒体基因、形态学和栖息地指标的两种鼢鼠分类研究

以祁连山东段高寒草甸区栖息的鼢鼠(Eospalax spp.)为研究对象,通过分子系统学、形态学和栖息地特征调查相结合的方法对区域内鼢鼠的分类地位进行了研究。利用分子生物学技术,测定了线粒体D-loop 序列,构建了系统发育树并计算了鼢鼠间遗传距离。测量了鼢鼠头骨指标以及体貌形态特征,并调查了不同鼢鼠栖息地草地类型、优势种植物及土壤紧实度等。结果发现4 个采样地的鼢鼠属两个不同种,即甘肃鼢鼠(Eospalax cansus)和高原鼢鼠(Eospalax baileyi)。两种鼢鼠的遗传距离为0.147;眶间宽、听泡宽在两性间均差异显著(n_雄=14,n_雌=16,P < 0.05),颧宽在雄性间差异显著(n_雄= 14,P < 0.05);甘肃鼢鼠尾部和后足有稀疏短毛,而高原鼢鼠则有密毛。甘肃鼢鼠主要栖息在海拔较低的高寒草甸区,其优势植物主要有矮嵩草(Kobresia humilis)、蕨麻(Potentilla anserina )、早熟禾(Poa annua);高原鼢鼠主要栖息在海拔较高的高寒灌丛草甸区,其优势植物主要有早熟禾(Poa annua)、金露梅(Potentilla fruticosa)、披碱草(Elymus dahuricus),但两者栖息地的土壤紧实度无差异(P >0.05)。本研究结果为同区域分布甘肃鼢鼠和高原鼢鼠的野外鉴别提供技术依据。

Classification of two zokor species based on mitochondrial gene,morphological and habitat indices

This paper reports a study on zokors sampled from four localities in alpine meadows in the eastern Qilian Mountains in NW China. We studied the taxonomic status of zokor in small regions by molecular phylogenetic, morphological and habitat features. We sequenced the mitochondrial D-loop sequences, reconstructed phylogenetic trees and estimated genetic distances. In addition, we measured the zokors’ skulls and compared their morphologies. Finally, we investigated the habitat vegetation types, the dominant species of plant, and soil compactness of thezokor habitats. The results showed that the zokors belong to two species，Eospalax cansus and Eospalax baileyi, from four different samples. There were significant differences in orbital width and the tympanic bullae (n_male= 14, n_female = 16,P＜0.05) between the two zokor species, and a significant difference in zygomatic breadth between males of the two zokor species (n_male= 14, P＜0.05). The two zokor species were also obviously different in external characters. E. cansus had spare and short hair on the tail and metapodia. However, E. baileyi had dense hair on the tail and metapodia. E. cansus prefer to live in alpine meadow at lower altitudes.  The dominant plants of its habitat were Kobresia humilis, Potentilla anserina, and Poa annua. E. baileyi prefer to live in higher altitude alpine shrub meadows. The dominant plants of its habitat were Poa annua, Potentilla fruticosa and Elymus dahuricus. There were no differences in soil compaction (P＞0.05) between two zokors’ habitats. This study has provided some technical basis to distinguish E. baileyi and E. baileyi in the field.