Neodon

Abstract: During a faunal survey in southern Xizang, we collected 27 specimens of voles that could not be identified as any knownspecies in the Arvicolinae. These specimens shared the following morphological characteristics, not corresponding withany other arvicoline species: the first lower molar possessed five closed triangles, the third upper molar exhibited eitherfour or three inner angles, and the tails of all specimens measured 30% of the body length. Their proximal baculum of theglans was very sturdy and trumpet-shaped, the distal baculum was tongue-like and sturdy, and the lateral bacula were veryshort. Molecular phylogenetic analyses based on nucleotide sequences of the mitochondrial cytochrome b (cyt b) geneclustered these specimens as a distinct lineage within the genus Neodon. According to the morphological and moleculardata, we described them as a new species, Neodon linzhiensis. Our phylogenetic analysis strongly supported that Lasio- podomys fuscus, Phaiomys leucurus, Neodon sikimensis, N. irene and the new species formed a monophyletic group, notincluding N. juldaschi. We suggested that L. fuscus and P. leucurus should be transferred to Neodon and that N. juldaschi should be removed from this genus. Following our new delineation of Neodon, we proposed a redefinition of the morphological diagnostic characters of the genus.

Abstract: N a d a c h o w s k i A., Z a g o r o d n y u k I. 1996. Recent Allophaiomys-like species: Pleisto­ cene relicts or a return to an initial type. Acta zool, cracov., 39(1): 387-394. Abstract. Recent Allophaiomys-like voles from the Palaearctic belong to Blanfordimys, Phaiomys and Neodon and form a group of about 6-8 species. They are characterized by a number of primitive features, e. g., simple molar morphology and high diploid chromosome numbers. Their ranges are small and located in the southern parts of the distribution of Arvicolini. All these features are characteristic of Pleistocene relicts. Mechanisms in the evolution of Allophaiomys Microtus are discussed.

Abstract: The species of Lasiopodomys Lataste 1887 with their related genera remains undetermined owing to inconsistent morphological characteristics and molecular phylogeny. To investigate the phylogenetic relationship and speciation among species of the genus Lasiopodomys, we sequenced and annotated the whole mitochondrial genomes of three individual species, namely Lasiopodomys brandtii Radde 1861, L. mandarinus Milne-Edwards 1871, and Neodon (Lasiopodomys) fuscus Buchner 1889. The nucleotide sequences of the circular mitogenomes were identical for each individual species of L. brandtii, L. mandarinus, and N. fuscus. Each species contained 13 protein-coding genes (PCGs), 22 transfer RNAs, and 2 ribosomal RNAs, with mitochondrial genome lengths of 16,557 bp, 16,562 bp, and 16,324 bp, respectively. The mitogenomes and PCGs showed positive AT skew and negative GC skew. Mitogenomic phylogenetic analyses suggested that L. brandtii, L. mandarinus, and L. gregalis Pallas 1779 belong to the genus Lasiopodomys, whereas N. fuscus belongs to the genus Neodon grouped with N. irene. Lasiopodomys showed the closest relationship with Microtus fortis Buchner 1889 and M. kikuchii Kuroda 1920, which are considered as the paraphyletic species of genera Microtus. TMRCA and niche model analysis revealed that Lasiopodomys may have first appeared during the early Pleistocene epoch. Further, L. gregalis separated from others over 1.53 million years ago (Ma) and then diverged into L. brandtii and L. mandarinus 0.76 Ma. The relative contribution of climatic fluctuations to speciation and selection in this group requires further research.

Abstract: The common vole, Microtus arvalis belongs to the genus Microtus in the subfamily Arvicolinae. In this study, the complete mitochondrial genome of M. arvalis was recovered using shotgun sequencing and an iterative mapping approach using three related species. Phylogenetic analyses using the sequence of 21 arvicoline species place the common vole as a sister species to the East European vole (Microtus levis), but as opposed to previous results we find no support for the recognition of the genus Neodon within the subfamily Arvicolinae, as this is, as well as the genus Lasiopodomys, found within the Microtus genus.