Geographic variation of the large-eared field mouse (Apodemus latronum Thomas, 1911) (Rodentia: Muridae) with one new subspecies description verified via cranial morphometric variables and pelage characteristics

Abstract

Background: The large-eared field mouse (Apodemus latronum Thomas, 1911), a common rodent, mainly inhabits southwestern China. Since its first description nearly a century ago, there have been numerous taxonomical and morphological arguments as to its validity, but relatively little work was done on mapping out the geographic variations observed in samples of the species. In this study, we used 142 specimens of A. latronum from Xizang, Sichuan, and Yunnan to conduct a multivariate analysis, coefficient of difference (CD) analysis of cranial measurements, and a comparison of some pelage characteristics. Results:The results of the analysis on 15 measurable cranial characters indicated that the specimens from Lijiang, Weixi, and Binchuan areas of the Yunnan province are apparently different from all the other specimens of A. latronum described so far and are allopatrically distributed. Conclusions: These samples form the core of our new description for A. latronum lijiangensis subsp. nov. as a new subspecies, and a detailed discussion on the relationships between the differentiation of A. latronum and its evolvement in southwestern China is provided.

中国姬鼠属的核型研究

“…In addition, extensive geographical divergences within the species have been reported for morphological and genetic traits in East Asian Apodemus species: e.g., A. chevrieri ( Yue et al, 2012 ), A. agrarius ( Sakka et al, 2010 ), A. draco ( Fan et al, 2012 ; Kaneko, 2010 , 2012 , 2015 ; Sakka et al, 2010 ), A. ilex ( Kaneko, 2010 , 2012 , 2015 ; Liu et al, 2012 ), A. latronum ( Kaneko, 2010 , 2012 , 2015 ; Li & Liu, 2014 ; Sakka et al, 2010 ), A. semotus ( Hsu et al, 2001 ), A. peninsulae ( Kaneko, 2010 , 2012 , 2015 ; Sakka et al, 2010 ; Serizawa et al, 2002 ), A. speciosus ( Kageyama et al, 2009 ; Shintaku et al, 2012 ; Shintaku & Motokawa, 2016 ; Suzuki et al, 2004 ; Tomozawa et al, 2014 ; Tomozawa & Suzuki, 2008 ), and A. argenteus ( Suzuki et al, 2004 ). These complex patterns are thought to have formed through geographic isolation and genetic exchange (e.g., A. speciosus between Robertsonian chromosome races; Shintaku & Motokawa, 2016 ; Suzuki et al, 2004 ; Tomozawa & Suzuki, 2008 ) after the formation of each species.…”