Taxonomy and phylogenetic relationship of zokors

Abstract

Zokor (Myospalacinae) is one of the subterranean rodents, endemic to east Asia. Due to the convergent and parallel evolution induced by its special lifestyles, the controversies in morphological classification of zokor appeared at the level of family and genus. To resolve these controversies about taxonomy and phylogeny, the phylogenetic relationships of 20 species of Muroidea and six species of zokors were studied based on complete mitochondrial genome and mitochondrial Cytb gene, respectively. Phylogeny analysis of 20 species of Muroidea indicated that the zokor belonged to the family Spalacidae, and it was closer to mole rat rather than bamboo rat. Besides, by investigating the phylogenetic relationships of six species of zokors, the status of two genera of Eospalax and Myospalax was affirmed because the two clades differentiated in phylogenetic tree represented two types of zokors, convex occiput type and flat occiput type, respectively. In addition, the two origins in Eospalax were found diverged at 3.71 million years ago (Ma) based on estimation of divergence time. It is suggested that the climate and ecology changes caused by the Qinghai-Tibet Plateau uplift event in 3.6 Ma led to the inner divergence of Eospalax. The intraspecific phylogenetic relationships of partial zokors were well resolved, the two clades of Eospalax cansus represented two geographical populations, respectively, and the divergent pattern of Eospalax baileyi was characterized by allopatric divergence spatially. In this study, we explored the taxonomic status and phylogenetic relationships of Myospalacinae at the molecular level. These works would be significant to understanding the evolutionary process and to clarify the mechanism of differentiation of Myospalacinae.