Background:During fieldwork conducted in the Bac Yen District of Son La Province, near the Ta Xua Nature Reserve, a representative of a previously never registered genus and species of rodent in Vietnam, the Yunnan field mouse (A. ilex O. Thomas, 1922), was discovered. New information:This finding significantly expands our knowledge of the distribution of Apodemus species in northeastern Indochina. Morphological and genetic analysis of the specimen ruled out accidental introduction and established that the Vietnamese population is natural and belongs to the eastern phylogenetic branch of this species, which also inhabits the southern Yunnan-Guizhou Plateau, as well as the upper reaches of the Mekong, Hong Ha, and Da Rivers. Thus, the list of rodent species and genera in Vietnam has been expanded with a new species. Data on the species' geographic distribution across its range are also provided.

We surveyed the distribution of small terrestrial mammals along the Da (Black) River in the Bac Yen district, Son La province, Vietnam. We recorded 21 species in the area. Species identifications were carried out using morphological and genetic methods in accordance with up-to-date taxonomy. The Da River is traditionally considered a zoogeographic boundary dividing different biogeographic regions in northern Vietnam. Our study was aimed at testing whether it can really be considered as such. Based on the observed distributions, we conclude that the water course is not the distribution boundary for 14 species out of 21 found in the area. Out of the seven remaining species, only those which are associated with the Chinese mountain-forest faunal complex demonstrate their southern boundary along the Da River. Thus, it is unjustified to consider this river as a biogeographic boundary for mammals.

The paper presents novel findings of little-known species of rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, with the first morphological and genetic characterisation and taxonomical description of the new species, T. taxuansis. The study also summarises all the data available on this genus species distribution, museum collections and notes on its taxonomy, which are important to establish the proper conservation status of the species. An exhaustive map of the findings is provided, along with a refined taxonomic key for all six currently morphologically characterised species of the genus. It is shown that, based on the data available to date, the genus is still far from complete. Most species, apparently, do not need a special conservation measure; their status may be established as Least Concerns and Near Threatened (B1a+2a) and the current population trend is stable (IUCN). The paper introduced innovative findings regarding lesser-known rodents, the blind tree mice Typhlomys in Son La Province, Vietnam, along with the primary morphological and genetic identification and taxonomic explanation of the novel species T. taxuansis.

The paper presented novel findings of little-known species of rodents the Tonkin limestone rat Tonkinomys daovantieni in Cao Bang Province, Vietnam with its morphological and genetic characterisation. The study summarises data on the distribution of this data deficient species, available museum collections, genetic samples, information on its taxonomy and ecology, important to establish the proper conservation status of the species. An exhaustive map of the findings is provided. It is shown that, based on the data currently available, the species does not require taxonomic revision and also, apparently, does not need a special conservation measure; its status may be established to date as Near Threatened B1a+2a and the current population trend - Stable, IUCN.

Based on new molecular data for mitochondrial ( Cyt b ) and nuclear ( IRBP , RAG1 ) genes, as well as an extensive analysis of morphological material, we accessed actual species taxonomy and relationships among Asian red-cheeked squirrels Dremomys distributed in eastern Indochina and southern China. Phylogenetic analyses demonstrated that Asian red-cheeked squirrels, which are currently attributed to D. rufigenis , are not homogenic but instead consisted of two independent species-level clades—northern and south-central. The latter clade was additionally subdivided into two highly divergent clades based on Cyt b gene phylogeny. In spite of multidimensional statistics approach applied (PCA) only minor cranial differences were found between populations of study what lay a basis to treat it as cryptic species. Based on our findings, red-cheeked squirrels inhabit northern Vietnam and southern China, which are usually attributed to D. rufigenis , should be treated as distinct genetic species D. ornatus Thomas, 1914. In ones turn, based on its peculiar external morphology we can attribute the specimens from southern and central Vietnam to D. rufigenis proper and treat them as D. rufigenis fuscus Bonhote, 1907 and D. r. laomache Bonhote, 1921, respectively.

Wide scope of investigations in ecology and biodiversity has been held during last century in Indochina and Sunda region, but in terms of fauna of mammals, Southeast Asia is still remains one of underinvestigated region in the World. It can be illustrated by the facts that new species have repeatedly being described from Laos, Northern Vietnam and Thailand during last decade [Averianov et al., 2000; 2,3,5,6,9] and there are good reasons to believe that the aria can present to a zoological science a lot of interesting finds. In this way, new species and genus was described in 2009 [10] in Son La province, Northern Vietnam and was named Pseudoberylmys muongbangensis. In spite of detailed morphological description, an illustrative materials did not allow to perform careful comparative taxonomical analysis based on the data presented in paper, unfortunately, authors also did not perform any genetic analysis of specimens obtained, which can be used to appreciate the status of new taxon based on molecular data. The fact forced us to organize an independent expedition to obtain original materials from type locality to perform comparative morphological and molecular genetics analysis to validate a taxonomical status and evolutionary relationships of these animals.