Recent molecular systematic studies of arvicoline voles of the genera Neodon, Lasiopodomys, Phaiomys, and Microtus from Central Asia suggest the inclusion of Phaiomys leucurus, Microtus clarkei, and Lasiopodomys fuscus into Neodon and moving Neodon juldaschi into Microtus (Blanfordimys). In addition, three new species of Neodon (N. linzhiensis, N. medogensis, and N. nyalamensis) have recently been described from Tibet. Analyses of concatenated mitochondrial (Cytb, COI) and nuclear (Ghr, Rbp3) genes recovered Neodon as a well-supported monophyletic clade including all the recently described and relocated species. Kimura-2-parameter distance between Neodon from western Nepal compared to N. sikimensis (K2P = 13.1) and N. irene (K2P = 13.4) was equivalent to genetic distances observed between recognized species of this genus. The specimens sampled from western Nepal were recovered sister to N. sikimensis in the concatenated analysis. However, analyses conducted exclusively with mitochondrial loci did not support this relationship. The occlusal patterns of the first lower (m1) and third upper (M3) molars were simpler in specimens from western Nepal in comparison to N. sikimensis from eastern Nepal and India. Twelve craniodental characters and four external field measurements were examined from specimens of N. sikimensis from eastern Nepal and India, N. irene, and Neodon from western Nepal. Neodon from western Nepal were significantly different from N. sikimensis from eastern Nepal and India in ten out of 16 characters measured and from N. irene for all characters except ear height. Specimens from western Nepal were smaller in size than N. sikimensis from Eastern Nepal and India and larger than N. irene. Together the results of the molecular and morphological analyses indicate that Neodon from western Nepal are distinct under the phylogenetic, genetic and morpho species concepts.
Bibliographical noteFunding Information:
NP Grants in Aid of Research from the American Society of Mammalogists (http://www. mammalogy.org/committees/grants-aid) and Carolyn M. Glass Fund of the University of Vermont. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. The Department of National Parks and Wildlife Conservation, Nepal provided collection permits. We are grateful to the staff at the Center for Molecular Dynamics Nepal especially Jyoti Joshi and Priya Joshi for providing high quality sequences. We also thank Dr. Bruce Patterson, Dr. Adam Ferguson, and John Phelps at the Field Museum and Darrin Lunde and Nicole Edmison at the Smithsonian National Museum of Natural History, for providing access to the specimens in their research collections. Dr. Jan Decher of the Zoological Research Museum Alexander Koenig kindly provided photos of skulls previously examined by Nadachowski and Zagorodnyuk  and Dr. Paula Jenkins of the Natural History Museum in London kindly provided clarification of the status and source of the type series of N. sikimensis. We greatly appreciate the constructive comments and suggestions provided by two anonymous reviewers.
© 2019 Pradhan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.