Molecular Phylogeographical Structure And Cryptic Species Diversity Of Leopoldamys Edwardsi Complex(Rodentia:Muridae)

In 1987,phylogeography was defined by Avise for exploring historical reasons and formations by animal's distribution patterns in the evoluton,including studies on differentiations of interspecific and intraspecific populations.Also,it is an effective tool to reveal cryptic species diversity.Southern China is complicated in topographical structure and geographical features with many mountains;however,the impact of the complicated topographical features on species differentiations is under fully studied.It is controversial to realize the impact of Pleistocene climatic fluctuation on the phylogeographical structure and current geographical distribution range of species in this area.In this study,we studied Edward's Leopoldamys Leopoldamys edwardsi(Rodentia:Muridae)that is widely distributed in southern China and 4 subspecies were proposed in China,including L.e.edwardsi,L.e.gigas,L.e.hainanensis and L.e.milleti.The species type locality of L.edwardsi is located in Kuatun of Fujian.The mitochondrial genes(Cyt b,COXI)were utilized as molecular marker in this study.A total of 65 specimens of L.edwardsi were collected from 11 localities over 7 Provinces in China.The purpose of this study is to reveal the relationship between genetic structures of L.edwardsi and geographical distribution patterns,to realize the influences of the potential geographical barriers in southern China on the phylogeographical structure of L.edwardsi,to investigate the impact of Pleistocene climatic oscillation on historical demography,and to assess the cryptic species biodiversity.Four conclusions were suggested by results of this research,(1)all of L.edwardsi are divided into 3 reciprocally monophyletic matrilineal Lineages that corresponded to the different geographical regions.Lineage L1 is from Hainan Island,L2 from Jiangxi,Guangdong,Guangxi and Vietnam,L3 from Jiangxi,Hunan,Fujian,and Zhejiang;(2)the phylogeographical structure of L.edwardsi is obvious and its genetic structure is closely related to geographical patterns in southern China.L1 was isolated with L2 by Qiongzhou Strait,L2 and L3 were divided by Nanling-Wuyi Mountain Range,and Xuefeng Mountain was proved to be a major geographical barrier for the two subclades within L3(L3a and L3b);(3)the great topographical diversity in this region and Pleistocene climatic fluctuations might play common role in driving the genetic divergence,genetic diversity and historical demography of L.edwardsi;(4)based on phylogenetic relationship,K2P genetic distance and Bayesian species delimitation,we suggested that the 3 lineages should represent three distinct species,i.e.,traditionally described species L.edwardsi is a species complex(L.edwardsi complex).Lineage L1 that was traditionally defined as the subspecies L.e.hainanensis should be elevated to species status,the Hainan Edward's Leopoldamys L.hananensis;the L2 lineage,whose distribution region did not closely match those of currently recognized subspecies,should be considered as a cryptic species;Lineage L3 containing the type locality of subspecies L.e.edwardsi,should be correspond to L.edwardsi.