Systematics Taxonomy Study Of Niviventer Confucianus(Rodentia:Muridae) In Shandong Province,China

Niviventer confucianus is the most widely distributed species in Niviventer genus.It has subspecies differentiation at most.Since found by Milne Edwards in Sichuan,Baoxing,China,it's classification of inter and intra specific species has always been a lot of controversy.The current consensus view is that Niviventer con.fucianus is a species complex and may has many eryptic species.Shandong Province has unique geographical position.It is surrounded by sea on three directions.It has high habitat diversity in the province and border with neighboring provinces.Thomas(1908)first found a kind of Niviventer confucianus in Yantai,Shandong,which has different shape with those in other area,and named it N.c.sacer.Since then many scholars expanded the N.c.sacer distribution range and put forward that the area north of the Yangtze river are all the N.c.sacer distribution.However,some scholars research showed that the Niviventer confucianus in Shandong have significant differences in karyotype with.We also found during field investigation that Niviventer confucianus in Shandong are kind of different in tail color with those in other area.So we call into question about the classification of the position of Niviventer con.fucianus in Shandong.In this research,we combine molecular systematic taxonomy and morphological method to comprehensively explore the classification status of Niviventer con.fucianus in Shandong.The main results show that:(1)Niviventer confucianus is a species complex in China.It can be divided into Central,Southeast,Shandong,Tibet&Yunnan four lineages.(2)Niviventer confucianus in Yantai,Weihai,Taishan,Laiwu,Zibo,Mengshan in Shandong Province formed a separate lineage in phylogenetic tree and haplotype network.The genetic distance between this lineage and other lineages 1s above 0.053.Automatic Barcode Gap Discovery method also show Niviventer con.fucianus in these area in Shandong is a separate population.(3)Niviventer confucianus Shandong lineage is closest to N.bukit.(4)Nivivente,confucianus Shandong lineage has significantly larger skull than Niviventer confucianus in other area,but has no significant difference between the skull form.(5)Niviventer confucianus Shandong lineage has significantly larger external and skull shape than Niviventer confucianus Central lineage,which has overlap distribution range in Zibo,Mengshan in Shandong Province.But there is no significant difference between skull form of two lineages.This study shows that Niviventer confucianus Shandong lineage is a cryptic species.It has significant differentiation with Niviventer confucianus in other lineages,which is mainly embodied in the external shape and size on the skull.Here,we speculate that the uniqueness of Niviventer confucianus Shandong lineage may because of the isolated habitat by the vast plain of Shandong Province.The isolation may hinder gene flue between different lineages of Niviventer confucianus.And the reason of close relationship with N.bukit may because of parallel evolution.But the specific reasons still need to be explored.