Abstract Mate choice is a key driver of reproductive fitness and a central topic in behavioral ecology. Although integrating behavioral observations with paternity analyses can provide powerful insights into mate choice, such combined approaches remain rare in non-human primates. Here, we conducted a 1-year study on a free-ranging troop of Taihangshan macaques (Macaca mulatta tchelinesis) in northern China. Using behavioral observations and microsatellite genotyping, we examined female mating patterns via Friedman tests and compared offspring numbers among male rank/age groups via Kruskal–Wallis tests. Female copulations were biased to high-ranking and prime-aged males, and paternity was also biased toward these males. Notably, one low-ranking immigrant male and inferred extra-group males also achieved reproductive success. Although male–male competition possibly contributed to the observed biases toward high-ranking/prime-aged males and the success of immigrant/extra-group males, our observations of sexual interference suggested that female choice also played an important role. Females likely preferred high-ranking males for direct benefits (e.g., resource access and protection) and prime-aged males for their higher reproductive capacity. In addition, novel (new immigrant or extra-group) males may also have a reproductive advantage, reflecting female strategies to increase offspring genetic diversity or avoid inbreeding. Our findings revealed complex female reproductive strategies and contribute to the understanding of sexual selection in primates.

Studying the demographic history of wildlife populations provides fundamental information for conservation and sustainable development. The rhesus macaque (Macaca mulatta) is the most widely naturally distributed nonhuman primate species; however, local populations can face extirpation due to human disturbance. This study investigated the demographic history of free-ranging Taihangshan macaques (M. mulatta tcheliensis) in the Wulongkou area, Jiyuan City, China, a site developed for tourism in the early 1980s and representative of wildlife-based tourism in China. The key findings demonstrated that the Taihangshan macaque population in the southern Wulongkou area has experienced significant fluctuations over the past three decades. The mean group size tended to return to its historical average size. Natality was relatively stable from 2012 to 2022 and then increased, and newborn mortality increased from 2012 to 2019 and then decreased since 2020. Many males remained in their natal group or dispersed to neighboring groups within the same area. These findings suggested that the Taihangshan macaque population may be constrained by environmental factors rather than food availability, as food has been regularly provisioned since the onset of tourism. We emphasize the need for future studies to identify the key challenges and to incorporate population genetic analysis to better evaluate the future viability of the Taihangshan macaque populations.

Alpha male replacement occurs in many group-living non-human primates, but its characteristics remain under-explored. Species of the genus Macaca live in multi-male, multi-female groups and are structured into four levels of social styles, which may impact alpha male replacement. Rhesus monkeys (Macaca mulatta) are classified as Grade 1, yet little is known about alpha male replacements in this species. This study investigated the occurrence and characteristics of alpha male replacements in rhesus monkeys inhabiting the southern end of Taihang Mountains, China. The types of alpha male replacements included succession (8/11), Rank Reversal (1/11), and Group Fission (2/11). The average age at which adult males took the alpha rank was 10.2 (±4.1, n = 11) years of age. Their average social rank prior to attaining alpha rank was 3.91 (±3.05, n = 11). The average tenure of alpha males after 2017 was 2.6 (±1.4, n = 5) years, which appeared shorter than that before 2017 (>7.5 ± 2.9 years, n = 4). The occurrence of alpha male replacements did not significantly correlate with group sizes, natality, the ratio of adult males to adult females, or the proportion of immatures. Compared with tolerant Macaca species, alpha male replacement in rhesus monkeys tend to be biased toward Succession, a pattern that may be linked to their extremely despotic social style. This study suggests that social style could interact with changes in social structure, deepening our understanding of the evolution of primate social systems.

Abstract Zoogeographical divisions are shaped by species distribution patterns and ecological factors, in which regions delineate areas of faunal similarity and boundaries mark transitions in species composition. However, the zoogeographical division of China has not been assessed using shared‐species similarity among multiple basic geographic units, and the effects of given ecological factors on zoogeographical regions and their boundaries in China remain unclear. Herein, using the multivariate similarity clustering analysis method, we delineated the zoogeographical areas of China based on the distribution data of terrestrial vertebrate species. Then, we assessed the effects of ecological factors on zoogeographical subrealms, regions, and their boundaries by adopting generalized linear models and hierarchical generalized linear models. The results showed that the zoogeographical patterns of China comprised two realms, three subrealms, and eight regions. Contemporary climate, past climate change, vegetation, and terrain influenced the formation of subrealms, while contemporary climate, past climate change, vegetation, terrain, and tectonic movements influenced the formation of regions. Moreover, contemporary climate, past climate change, and tectonic movements shaped intersubrealm boundaries, while contemporary temperature seasonality governed interregion boundaries. Our findings provide a comprehensive quantitative analysis of zoogeographical patterns in China, offer a useful analytical framework for research on biogeographical divisions, and provide insights into the ecological drivers of biogeographical divisions across different spatial scales and biotic groups.

Biogeographical division refers to dividing a given area into identifiable biogeographical realms and their corresponding boundaries, based on the geographical distribution of selected biological taxa. Previous studies have generally lacked clustering analyses of faunal compositional similarity across multiple geographical units and have rarely assessed how ecological factors shape zoogeographical divisions across different spatial scales. Here, we reevaluated the world’s zoogeographical realms using the multivariate similarity clustering analysis (MSCA) method based on the genus-level distributional data for terrestrial vertebrates, and then tested the relative importance and statistical significance of ecological factors on the formation of realms and their boundaries using generalized linear model and hierarchical generalized linear model, respectively. The results showed that: 1) totally six world’s zoogeographical realms, the Afrotropical, Australian, Nearctic, Neotropical, Oriental, and Palearctic realms had been delineated, and the Oriental–Australian boundary was more consistent with the Weber Line; 2) current climatic temperature and vegetation influenced the formation of zoogeographical realms, whereas the effects of current climatic precipitation, past climate, and tectonic movement varied among realms; 3) tectonic movement and precipitation seasonality of current climate significantly influenced the formation of boundaries between realms; and 4) the positions of zoogeographical boundaries between realms were dynamic and taxon-dependent. Our findings were expected to provide new insights into biogeographical researches.

Clarifying formation processes and dispersal history of given taxon provides important insights into understanding the origins and persistence of regional biodiversity. Here, we investigated the phylogeny, divergence times, genetic diversity, population structure, and demographic history of Uropsilus populations distributed across the Mts. Qinling-Dabashan area using two mitochondrial and three nuclear loci. The results indicated that Uropsilus populations in the Mts. Qinling-Dabashan area are composed of U. funiushanensis (east) and U. sp. 5 (west), with their most recent common ancestors dated back to 2.18 Ma (95% CI: 2.00-2.67 Ma). The populations exhibit pronounced east-west genetic differentiation, with additional north-south structuring observed within each species. During the Last Glacial Maximum, both U. funiushanensis and U. sp. 5 experienced population expansion, and the Hanjiang River posed a minimal barrier to north-south gene flow, whereas subsequent Holocene warming led to increased isolation. Overall, the Mts. Qinling-Dabashan have consistently provided suitable habitats, maintaining the genetic diversity of U. funiushanensis and U. sp. 5. These findings were expected to provide new insights into the speciation, historical dispersal, and the maintenance of genetic diversity of Uropsilus in the Mts. Qinling-Dabashan area of China.

The gut microbiome is a key regulator of host nutritional intake, growth, and health, playing an essential role in mediating host adaptation to environmental changes. The northernmost population of rhesus macaque, Taihangshan macaque (Macaca mulatta tcheliensis), faces severe survival challenges, such as food shortages and harsh temperatures during winter and early spring. Previous studies have shown that they cope with seasonal changes through behavioral adaptations, such as adjusting food resources and flexibly regulating macronutrient intake. However, the role of the gut microbiome in supporting the seasonal adaptation of Taihangshan macaques remains unclear. Herein, we investigated seasonal variations in gut microbiome alpha diversity, composition, and functions from fecal samples of Taihangshan macaques using metagenomic analysis. The results showed that: (1) totally 435 non-redundant metagenome assembled genomes (MAGs) were generated; (2) alpha diversity was significantly higher in spring and winter than in summer and autumn; and (3) in winter, pathways of fatty acid biosynthesis and essential amino acid (EAA) biosynthesis, as well as CAZymes (GH3 and GH5) involved in cellulose and hemicellulose degradation, were significantly enriched. In contrast, pathways related to carbohydrate, energy, and glycan biosynthesis and metabolism, along with CAZymes (GT8 and GH23) potentially facilitating fat synthesis and storage, were enriched in summer. These functional adjustments likely help the host cope with seasonal variations in food availability and environmental conditions. Overall, this study provides new insights into how the gut microbiome responds to seasonal changes in diet and environmental factors in mammals inhabiting temperate forests.

Understanding tripartite interactions among food plants, their associated microbiota, and herbivorous animals is crucial for advancing biodiversity conservation in grassland ecosystems. This study explores how plant palatability influences the epiphytic and endophytic microbiota of grassland plants and affects the gut microbiota of Brandt's vole (Lasiopodomys brandtii), a key but declining herbivore in Inner Mongolian steppes. We analyzed the microbial communities of eight candidate food plants and the fecal microbiota of field and captive voles using 16S rDNA high-throughput sequencing. Results show that high-palatable plants (e.g., Leymus chinensis) had significantly lower endophytic bacterial diversity compared to low-palatable plants (e.g., Cleistogenes squarrosa). Low-palatable plants were enriched with Actinobacteria (24.66 %) and exhibited higher secondary metabolite synthesis capabilities, such as antibiotic production by Pseudomonas, potentially deterring herbivory. In contrast, high-palatable plants were dominated by Proteobacteria (98.45 %), including genera like Ralstonia which enhance plant digestibility, and suppress plant defenses to prioritize growth. Crucially, field Brandt's voles consuming diverse plants show Bacteroidetes-dominated microbiomes for fiber digestion, while laboratoryreared voles on restricted diets develop dysbiosis with pathogenic Proteobacteria. Notably, 15 microbial phyla were shared between plant surfaces and vole guts, suggesting microbial transmission. These findings suggest a coevolutionary continuum wherein low-palatable plants utilize microbial defenses to resist herbivory, while high-palatable plants promote digestibility and vole attraction. This continuum shapes herbivore foraging behavior and nutrient cycling. We conclude that supporting diverse vegetation and microbe-mediated interactions is critical for conserving Brandt's vole populations and maintaining ecological balance in grassland systems.

Spatial learning and memory are critical for animal survival, enabling adaptation to changing and unpredictable environments. These abilities enhance competitiveness and fitness by supporting navigation, resource acquisition, and predator avoidance. Understanding how spatial learning and memory vary among species with different living conditions can provide insights into the evolutionary pressures shaping these skills. In this study, we examine learning and memory abilities from an ecological perspective by comparing Brandt's voles (Lasiopodomys brandti) with Kunming mice (Mus musculus) using complex maze tests. Brandt's voles exhibited significantly shorter total task time (TTT) and fewer number of errors (NEI) compared to Kunming mice, highlighting superior spatial learning ability. Short-term memory (STMR) results revealed no significant differences between species as well as sex. For long-term memory (LTMR), Brandt's voles demonstrated consistently better retention across all time points, reflected in lower TTT and NEI. While short-term forgetting rates (STFR) were comparable between species, long-term forgetting rates (LTFR) indicated that Kunming mice exhibited higher rates of memory loss over extended periods than Brandt's voles, with male mice exhibiting higher rates of memory decline than females. Overall, the findings suggest that Brandt's voles possess enhanced spatial learning and long-term memory capacities, likely reflecting adaptations to their living condition. This study contributes to our understanding of species- and sex-related differences in spatial learning and memory, providing evidence for the ecological basis of these cognitive traits in response to environmental challenges.

ABSTRACT Shrew moles (Uropsilus), belonging to subfamily Uropsilinae of family Talpidae, were predominantly found in Myanmar, Vietnam, Bhutan, and Southwestern China. However, the extent distribution range of species within Uropsilus remains unclear. In 2022, we collected 18 specimens of Uropsilus from the western mountains of Henan Province in central China. Based on the mitochondrial (CYT B) and nuclear (RAG1 + RAG2) genes, the phylogenetic relationships, divergence times, and species delimitation of Uropsilus were analyzed. The results showed that the genetic distance of CYT B between new species and other species of Uropsilus ranged from 8.44% to 18.23%; the new species was a distinct valid species and speciated in the early Pleistocene (2.16 Ma, 95% CI = 2.00–2.65) based on phylogenetic analyses. Morphologically, the new species was distinguishable from the other species of Uropsilus by its yellowish–brown dorsum and ash‐black venter, short tail, slender and curved zygomatic arch, upper inward‐curved I1, and lack of a gap between I1 and I2. The combined results of morphological and molecular phylogenetic analysis indicated that the samples from Henan Province represented a new species—Uropsilus funiushanensis sp. nov. The specimens collected from the mountainous area of western Henan Province and Shennongjia in Hubei Province were identified as the same species. We suggested the evolutionary mechanism of the dental formula of U. funiushanensis and U. soricilus groups should be explored in the future.

Grasslands play an indispensable role in global ecological balance. However, land utilization practices such as mowing, grazing, and mining have led to degradation, affecting plant diversity and reducing carbon (C) and nitrogen (N) stocks. Revealing these degradation mechanisms after various land utilization practices is essential for implementing effective management practices to restore and sustain degraded grasslands. This study examines the effects of different land use types-mowing, light grazing, heavy grazing, and mining-on plant community characteristics, biomass, soil C and N dynamics in the Hulunbuir Grassland of Inner Mongolia. Our results revealed that across 50 herbaceous species, dominant vegetation shifted significantly: light grazing favored native grasses like Cleistogenes squarrosa and Artemisia frigida, while heavy grazing and mining promoted invasive species (e.g., Taraxacum mongolicum). Plant diversity and biomass were highest under mowing, but mining reduced species richness by 35 % and biomass by 50 % compared to mowing. Soil organic carbon (SOC) and total nitrogen (STN) stocks varied significantly across land-use types and plant growth phases, peaking in mowing sites (SOC: 9.85 ± 1.45 g/kg; STN: 1.55 ± 0.05 g/kg at 0-20 cm depth) and declining sharply in mining areas (SOC: 3.44 ± 0.46 g/kg; STN: 0.76 ± 0.06 g/kg). Strong correlations linked plant diversity and root biomass to SOC and STN retention, whereas Asteraceae biomass showed minimal influence. Structural equation modeling demonstrated that land use influenced SOC and STN stocks primarily through indirect effects on plant, root, and litter biomass rather than direct impacts. These findings underscore the need for daptive, site-specific restoration frameworks to mitigate degradation, prevent invasive species encroachment in mining areas and grazing livestock for sustainable grassland restoration.

Rodents are important reservoirs of zoonotic pathogens, and the Capillaria hepatica they carry pose a potential threat to public health in grassland ecosystems. Climate-driven changes in precipitation show complex effects on disease ecology, particularly in steppe grasslands where extreme weather events are becoming increasingly frequent. Here, to investigate the effects of precipitation patterns on the epidemic dynamics of C. hepatica in host populations, we conducted a 7-year manipulation experiment in twelve 0.48-ha field enclosures in semiarid steppe grassland. We found that rainfall increases in the early growing season intensified the infection rate and infection intensity of the parasite. Structural equation model demonstrated that additional precipitation indirectly affected epidemic dynamics by changing population parameters including body weight and population size. On the other hand, C. hepatica in the enclosure also exhibited obvious male-biased parasitic characteristics, which were not observed in the wild population. In brief, our results provide experimental evidence for the impacts of rainfall patterns on parasite epidemiological dynamics at population level and highlight the importance of early rainfall increase on the parasite transmission in the semiarid grassland.

Nutrition is a complex and contested area in biomedicine, which requires diverse evidence sources. Nonhuman primate models are considered an important biomedical research tool because of their biological similarities to humans, but they are typically used with little explicit consideration of their ecology and evolution. Using the rhesus macaque (RM), we consider the potential of nutritional ecology for enriching the use of primates as models for human nutrition. We introduce some relevant aspects of RM evolutionary and social ecology and discuss two examples where they have been used in biomedical research: obesity and aging. We next consider how insights from nutritional ecology can help inform and direct the use of RM as a biomedical model. We conclude by illustrating how conceptual tools might inform the use of RM as a model for human nutrition and extracting insights from RM that might be relevant to broader theoretical considerations around animal model systems.

Rhesus macaque (Macaca mulatta), the iconic species of genus Macaca, is characterized by the greatest geographical distribution of all nonhuman primates and is an important resource in many wildlife-related tourism areas, especially in China. In the current study, the genetic diversity was assessed by ten microsatellite loci with DNA obtained from muscle tissue of deceased individuals of free-ranging but tourist-habituated rhesus population naturally inhabiting the Wulongkou Scenic Area, Jiyuan, China, where they have been exploited for tourism since the early 1980s. The results showed that the genetic diversity for the studied rhesus population was relatively lower compared with its wild and captive counterparts, and the samples collected from the population subdivision in the studied area could mask the finding. Therefore, we proposed that a group-based study of the genetic diversity would help to clarify the genetic structure/diversity of rhesus macaques in this area, and then reasonable management recommendations could be provided for the sustainable development of local wildlife-dominated tourism.

BACKGROUND: Global warming poses one of the most formidable challenges confronting the contemporary world, exerting extensive and profound impacts on both natural ecosystems and human society. Nevertheless, the detrimental effects of elevated temperatures on reproductive system in animals and humans remains elusive. METHODS: In this study, C57BL/6 mice were exposed to high ambient temperatures (HAT). Subsequently, the testes and sperm parameters of the mice were evaluated following the exposure. RESULTS: The HAT mice had significantly lower weight, food and water intake than those in the control group. The weight of testis and epididymis was significantly lower in the HAT group. The HAT group showed significant reductions in seminiferous tubule area, spermatogenic epithelium area, and seminiferous epithelium thickness. The HAT group exhibited significantly reduced sperm density, viability, and plasma membrane integrity rate. The HAT group exhibited a significantly elevated rate of sperm malformation. Moreover, the expression levels of Dnah8 and Dnah17, two genes associated with Multiple Morphological Abnormalities of the Flagella (MMAF), were markedly reduced in the HAT group. The proportion of TUNEL-positive cells significantly increased in the HAT group. Furthermore, there was a significant upregulation in mRNA expression levels of apoptotic genes Caspase-3 and Bax in the HAT group. Conversely, there was a notable decrease in mRNA expression level of anti-apoptotic gene Bcl-2. The concentration of MDA in the HAT group was significantly higher, while SOD activity and T-AOC were significantly lower. CONCLUSIONS: Therefore, it can be inferred that elevated air temperature leads to multi-layered damage to animal reproduction. This suggests that extreme high temperatures resulting from climate warming will have a detrimental impact on animal reproduction. This study provides support for elucidating the mechanism underlying the reproductive effects of high temperature.

Allomaternal behavior, such as allonursing, provisioning, transporting, cleaning, and protection by group members other than the infant's mother, is widely observed in nonhuman primates. Reduced food availability, high predation risk, infanticide, and high maternal reproductive costs are proposed as selective factors promoting allomaternal care. In this study, we examined patterns of allomaternal behavior in a multimale-multifemale group of Taihangshan macaques (Macaca mulatta tcheliensis) inhabiting a cold (winter temperatures can reach -20 °C), high-latitude (34°54'-35°42'N) environment in northern China. We found that 42.45% (45/106) Taihangshan macaques engaged in allomaternal behavior, including 59.52% (25/42) adult females, 66.67% (6/9) adult males, 75% (9/12) subadult females, and 20.83% (5/24) juveniles. Nulliparous female caregivers exhibited significantly higher frequency of allomaternal care than multiparous females, and caregiving behavior was associated with higher infant survival among inexperienced females, supporting the predictions of the "learning to mother hypothesis." Furthermore, the proportion of allomaternal care initiated by relatives was significantly higher than that initiated by nonrelatives, emphasizing the role of kinship in the evolution of allomaternal behavior in this species. Additionally, adult males participated in infant caretaking and provided more care to their genetic offspring compared with unrelated infants, which is consistent with the paternal investment hypothesis. Therefore, allomaternal caregiving appears to benefit mothers by reducing their infant care costs, while also providing inclusive fitness benefits and caregiving experience for caregivers.

Infant-care behavior, a range of caring behaviors by parental or alloparental individuals towards infants unable to live independently, plays a significant role in the survival of infants and the continuation of the species in non-human primates. During a behavioral ecological study of Taihangshan macaques, we observed 2 cases of infant adoptions by unrelated adult females. In case 1, a multiparous female adopted a lost infant from a neighboring group, with the infant being snatched back by her biological mother 35 days after the adoption. This is the first report of cross-group adoption in Macaca. In case 2, a nulliparous adult female, who had been once adopted by her elder sister, adopted an orphan from her group for 36 days. We describe the details of adoptions in Taihangshan macaques and explore possible reasons for adoptions to contribute to understanding the evolution of infant-care behavior and altruistic behavior of adoption in primates.

Pleistocene climatic oscillations exerted significant influences on the genetic structure and demography of rhesus macaque (Macaca mulatta) in eastern China. However, the evolutionary history of rhesus macaques in subtropical and temperate China remained unclear and/or controversial. Herein, we analyzed the autosomes, mitochondrial genomes, and Y-chromosomes from 84 individuals of Chinese rhesus macaque. The results revealed that (1) all individuals were clustered into pan-west and pan-east genetic groups, which exhibited Shaanxi Province as the northernmost region of western dispersal route of rhesus macaques in China; (2) in subtropical and temperate China, rhesus macaques were divided into four lineages (TH, DB, HS, and QL), and their divergence times corresponded to the Penultimate Glaciation (300-130 kya) and Last Glaciation (70-10 kya), respectively; (3) the individuals from Mt. Taihangshan (TH) are closely related to individuals from Mt. Dabashan (DB) in the autosomal tree, rather than individuals from Mt. Huangshan (HS) as indicated by the mitogenome tree, which supports the hypothesis that the ancestral rhesus macaques radiated into Mt. Taihangshan from Mt. Huangshan via Mt. Dabashan; and (4) the demographic scenario of the four lineages showed the ancestral rhesus macaques bottleneck and expansion corresponding to the suitable habitat reduction and expansion, which confirmed they had experienced northward recolonization and southward retreat events from Mt. Huangshan area via Northern China Plain to Northernmost China along with Pleistocene glacial cycles. This study provides a new insight into understanding how Pleistocene glaciation has influenced faunal diversity in subtropical and temperate China, especially for those exhibiting differential patterns of sex dispersal.

The dual impact of climate change and human activities has led to a sharp decline in global primate biodiversity.China,which has the most diverse primate species in the northern hemisphere,faces severe eco-logical threats during its transition from an agricultural to a modern society due to the expansion of modern ag-riculture,over-exploitation and consumption of natural resources,and excessive land development.In re-sponse,China has implemented various ecological conservation measures,including habitat restoration and protection.These efforts have made substantial progress in biodiversity conservation,with certain regions see-ing an increase in primate populations.This study conducted a systematic review of historical documents and field research data related to Chinese primates,evaluating the endangered status of primate species in China.Despite improvements in the habitats of most primate species and some population growth,many species still face severe threats,including declining and small populations.Species such as the Myanmar snub-nosed mon-key(Rhinopithecus strykeri),eastern black crested gibbon(Nomascus nasutus),and Hainan gibbon(N.hainanus)remain particularly vulnerable due to their limited distribution ranges and extremely small popula-tions.Insufficient scientific data,fragmented information,and a lack of comprehensive studies in conservation biology further exacerbate these challenges.Additionally,there is a notable lack of detailed population monito-ring data for species such as the Bengal slow loris(Nycticebus bengalensis),Pygmy slow loris(N.pygmae-us),Indochinese gray langur(Trachypithecus crepusculus),Shortridge's langur(T.shortridgei),and capped langur(T.pileatus),hindering the development of practical and targeted conservation management strategies.Therefore,for national biodiversity conservation,there is an urgent need for specialized primate surveys,enhanced habitat protection and restoration,and increased focus on cross-border conservation strate-gies and regional cooperation.Establishing a comprehensive and systematic research database platform,con-ducting continuous and in-depth research in primate biology.Additionally,strengthening public awareness on wildlife conservation remains essential.Such integrated and systematic efforts will provide scientific support for the current and future conservation and management of primate species in China.

The greater long-tailed hamster is primarily distributed in North Korea, Siberia (Russia), and central and northern China, while the Gansu hamster is restricted to southern Gansu Province, China. The genera Tscherskia and Cansumys have each been considered monotypic. The taxonomic status of these two genera has long been debated, and the specific status of T. ningshaanensis has also been contentious. Researchers have variously treated T. ningshaanensis as a subspecies of either T. triton or Can. canus. In this study, we estimated the phylogeny, divergence times, species delimitation, and biogeographical history of T. ningshaanensis by using one mitochondrial (CYT B) and three nuclear loci (GHR, IRBP, and RAG1) and compared the external and skull morphology variations between T. ningshaanensis and T. triton. The results showed that: 1) The genus Cansumys is a distinct genus in Cricetinae; 2) The notion that the genus Tscherskia is a monotypic genus is unsupported, T. ningshaanensis and T. triton were identified within this genus; and 3) The formation of T. ningshaanensis may have been driven by uplift of the Qinling Mountains. We conclude that T. ningshaanensis is a valid species within the subfamily Cricetinae.