Phallic Morphological Characteristics And Taxonomic Application Of 16 Species Of Muridae In China

Muridae is the second largest family of order RODENTIA in species numbers in China and is closely related to human life.Due to its high species abundance and rapid species diverfication,there are still problems in species morphological identification and taxonomy,and the morphological characteristics of many species are ambiguous in taxonomy and species identification.Phallic morphology is a branch developed from classic morphology taxonomy,and it occupies an important position in studying mammal taxonomy and phylogenetic relationships.Species are reproductively isolated,and the penis might be of specific as a mating organ.Due to the special position of the penile bone,it bears much less environmental pressure than other bones,it is relatively conservative in evolution;however,the morphological difference of penile bone is likely to be an important factor in reproductive isolation between species,it is likely more effectively differentiated between species especially more useful in identifying highly closed species than other external morphological features.As the same,it can reflect the phylogenetic relationships of species and genus.Penis morphology has certain advantages and can solve some controversial problems in taxonomy.Taxonomists believe that penis morphology is of great significance in taxonomic identification and can reveal phylogenetic information of species.This study described the penis of 16 Muridae species distributed in China by anatomic observations of penis,and compared the phylogenetic relationships among species of numerical taxonomic analyses to that of molecular phylogeny results.The results showed that the morphology of penis is specific between different genera.The characteristics of penis is converge in genus level but specific between species within the genus,and its morphological characters are stable with minor variation within species.Therefore,the morphology of the penis can be used for species taxonomy and identification,and can also reveals phylogenetic relationships in some extents in species and genus levels.The main results and innovations of this study are as follows:(1)molecular species identification for specimen is used to insure validity of species used to conduct penile morphology studies;(2)firstly reported the penile morphology of eight species including N.lotipes,N.huang,N.sacer,Apodemus ilex,Chiromyscus langbianis,Rattus andamanensis,Mus pahari,and M.caroli;(3)verified that phallic morphology is better in distinguishing highly related species than traditional taxonomic methods,such as the cases of N.confucianus and N.sacer;(4)firstly reported that three species are found to have dimorphism of penis morphology within species,including N.confucianus,N.sacer and Leopoldamys edwardsi;(5)phylogenenic cluster tree of phallic morphology was made and compared to molecular phylogenetic tree for the 16 Muridae species;(6)provided phallic morphological evidences for the distinct species position in taxonomy reported in recent years for N.sacer and A.ilex.