Based on a comparative investigation of morphological and genetic data, a taxonomic revision of the genus Niviventer in Vietnam and the adjacent regions of East Indochina was carried out. The phylogenetic relationships within 13 species (N. andersoni, N. excelsior, N. eha, N. brahma, N. culturatus, N. coninga, N. rapit, N. niviventer, N. confucianus, N. tenaster, N. fulvescens, N. langbianis and N. cremoriventer) were investigated based on a full set of cytochrome b sequences and the cytochrome coxidase subunit I genes that are currently available. The full species rank for N. huang and N. bukit, which previously were regarded as forms of N. fulvescens, was approved. The occurrence of the members of the Malayan complex of species (N. tenaster, N. bukit and N. cremoriventer) among the mammal fauna of Southern Vietnam was established. The geographical distribution of the genetic lineages/species in Indochina is specified. It was shown that eight Niviventer species, namely N. niviventer, N. confucianus, N. bukit, N. tenaster, N. fulvescens, N. huang, N. langbianis and N. cremoriventer, occur in Vietnam. Some species (N. bukit, N. huang and N. langbianis) were demonstrated to be sympatrically distributed, whereas the others (N. fulvescens N. huang and, apparently, N. cremoriventer N. langbianis) formed vicariate pairs. Four species (N. niviventer, N. confucianus, N. fulvescens, and N. langbianis), were found to inhabit Northern Vietnam and the adjacent provinces of China (Yunnan, Guizhou); four species (N. tenaster, N. bukit, N. huang and N. langbianis) were recorded in the mountain regions of Central Vietnam and Laos; and three others (N. bukit, N. cremoriventer and N. huang) were found to inhabit most of the plains in Indochina, including Southern Vietnam, Cambodia, and a part of Thailand. It should be stressed that N. huang (but not N. fulvescens as it is usually considered) is the most common Niviventer species in Indochina, and its distribution range stretches over the plains of Thailand, Cambodia and Vietnam up to the southeastern provinces of China. Craniometrical characters and indexes were studied by applying discriminant analysis; the species-specific pattern of skull proportions and its applicability for species identification were demonstrated for some of the characters and indexes. By morphological analysis of genetically verified specimens, morphologically detailed descriptions of the external appearance and structural traits of the skull were presented for all eight Vietnamese Niviventer species. Practical recommendations and guidelines for visual species identification are also given. The size of the body and skull, the comparative length and the specific pattern of coloration of the tail and tail tip as well as the dorsal side of the feet, the size and shape of the auditory bullae, the comparative length of the incisive foramina and the bony palatal bridge and the extent of development of supraorbital ridges were demonstrated to be the most informative features for species identification.

A revision of the genus Leopoldamys is presented, and both the species composition and distribution in Indochina and Sundaic regions is reinvestigated. The phylogeny of the genus is recovered based on Cyt b, COI, and IRBP gene analyses. Five basal and 16 secondary monophyletic phylogenetic lineages were identified. A taxonomic reassessment of the continental and Sundaic populations is performed based on morphological verification of the genetically defined clades. Six clades were recovered in the phylogenetic analyses and correspond to morphologically defined species: L. revertens (distributed in lowlands of eastern and central Indochina), L. herberti (western and central Indochina, northward to northern Vietnam), L. edwardsi (China and northern Vietnam, northward of 21°N), L. milleti (endemic of Dalat Plateau, southern Vietnam), L. sabanus (Borneo), and L. vociferans (lowlands of the Malacca Peninsula, northward to southwestern Thailand). The absence of proper L. sabanus in continental Indochina is revealed. The substitute name for the species known from the majority of Indochina under the name of L. sabanus should be L. revertens. The name L. neilli, which has been ascribed to populations from Thailand and Vietnam, is a junior synonym of L. herberti. Two related but rather divergent clades are found in Sumatra and the Malacca Peninsula. Based on their considerable genetic distances, these forms should be regarded as separate species from the L. sabanus type-bearing populations of Borneo, or as the members of L. sabanus polytypic superspecies. The substitute name for the lineage-bearing taxon from Malacca should be L. vociferans. The continental populations of Leopoldamys can be distinguished from each other by external and cranial characters and may be subdivided into four species. Two of these species (L. revertens and L. milleti) are well distinguished by external and cranial morphology, whereas the other two species (L. herberti and L. edwardsi) may be treated as sibling species that are difficult to distinguish based on morphological characters.

No abstract

Background: The taxonomic position of enigmatic pygmy dormouse Typhlomys (Rodentia: Platacanthomyidae) from Vietnam is reconsidered based on both morphology and sequence data. Results: The analysis of mitochondrial and nuclear genes has shown that the pygmy dormouse from Lao Cai Province of northern Vietnam belongs to a distinct phylogenetic lineage of Typhlomys. The DNA analysis has demonstrated a strong genetic difference (0.245 to 0.252 for the cytochrome oxidase gene (COI), 0.079 to 0.082 for interphotoreceptor retinoid-binding protein gene (IRBP), and 0.028 for the growth hormone receptor gene (GHR) between this lineage and the sample from South China. Multivariate analysis of cranial and dental data, as well as of some external characters, has also separated the Vietnamese population from the pygmy dormouse from Fujian in southern China, the type locality of Typhlomys cinereus (Bull Soc Philomath Paris 12:8-10, 1877).

No abstract