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A balanced bandpass filter (BPF) with a novel coupling scheme and source‐loaded coupling (SLC) technique is proposed. The J‐inverter is directly connected to the source or load, and the single‐band cell (SBC) is fed by the J‐inverter. Meanwhile, the J‐inverter is also coupled to a resonator. Equivalent differential‐mode (DM) and common‐mode (CM) circuits are presented, and their ideal frequency responses under DM and CM are also provided. Furthermore, the SBC equals paralleled short‐ and open‐circuited stubs in DM and equals two paralleled open stubs in CM. To validate the design concept, a four‐pole balanced BPF working at 2.66 GHz with fractional bandwidth (FBW) of 13.8% is designed and fabricated. Three transmission zeros (TZs) are generated, and the upper stopband suppression level reaches 34 dB. Meanwhile, a high CM rejection level attains 54 dB within the DM passband. [ABSTRACT FROM AUTHOR]

In this article, a novel coplanar waveguide (CPW) spiral cross resonators (SCRs) is introduced for creating a dual‐band balanced bandpass filter (BPF) with adjustable passbands. The resonant properties of the SCRs in both the differential mode (DM) and common mode (CM) are scrutinized. Furthermore, DM bisection offers two distinct parameters for internal coupling adjustment, enabling independent passband width control. A novel grounding wire feeding arrangement matches the external Q factor of the dual DM passbands. An additional stepped‐impedance short‐circuited conducting stub between resonators prevents excessive coupling while obtaining moderate bandwidths. Inherent CM suppression can be attained by distinguishing CM resonant frequencies distinct from the DM frequencies. To validate the design, a dual‐band balanced BPF designed and fabricated to operate at 2.42 and 5.2 GHz exhibits closely matching measured results compared to the simulated ones. [ABSTRACT FROM AUTHOR]

In this letter, a novel dual‐band bandpass filter (BPF) with independently controllable center frequencies, bandwidths, and transmission zeros (TZs) is presented. The proposed BPF is realized by using eighth‐mode substrate‐integrated circular cavities (EMSICCs) and coplanar waveguide (CPW) resonators. The CPW resonators are embedded in the upper surface of the EMSICCs, allowing for a compact size without additional circuit dimensions. Finally, a dual‐band BPF for WLAN is designed and fabricated with center frequencies of 2.45 and 5.2 GHz. The measured results closely align with the simulated ones, validating the performance of the filter. Multiple TZs are generated by cross‐coupling and source‐load coupling, which results in good out‐of‐band rejection performance. [ABSTRACT FROM AUTHOR]

Quasi‐reflectionless balanced bandpass filters (BPFs) using absorption network for common‐mode (CM) rejection and stopband extension are proposed and demonstrated. First, a quasi‐reflectionless balanced BPF is constructed by using absorption network and a uniform impedance resonator (UIR), where absorption network consists of lossy stubs loaded at both the input/output port and the ends of the coupling line (CLs). Owning to the resonating of absorption network, a three‐pole balanced BPF with CM and differential‐mode (DM) reflectionless performance are realized. Meanwhile, harmonic of DM is suppressed by exploring the loading position of the resistor. Second, to improve the selectivity of the filter, two open stubs are symmetrically loaded to the center of the UIR, a five‐pole quasi‐reflectionless balanced BPF with two transmission zeros are presented. Both proposed quasi‐reflectionless balanced BPFs are fabricated and measured. The measured results are in good agreement with the simulated ones, verifying the proposed design concept. [ABSTRACT FROM AUTHOR]

Hainan gibbons are among the world's most critically endangered primates, with a remaining population of only 35 individuals distributed across 5 social groups in the Bawangling Branch of the Hainan Tropical Rainforest National Park, China. Habitat conversion and forest fragmentation over the past 40 years have reduced their geographical distribution by 95%. In the absence of a quantitative assessment of the availability of remaining suitable habitat, it is unclear whether this species can survive to the end of this century. We used behavioral observations, ArcGIS, remote sensing, stereo optical imagery, and MaxEnt modeling to identify patterns of Hainan gibbon range use and compare changes in the distribution of suitable forest types and areas of forest fragmentation over the past 20 years (2000–2020). The results indicate that the combined range of the 5 extant Hainan gibbon groups totaled 14.89 km2. The home range of the smallest group (Group E, 3 individuals) was 1.51 km2, which likely represents the minimum home range size for this species. The remaining area of highly suitable and moderately suitable habitat totals 26.9 km2. However, habitat connectivity across the gibbon range is very low (less than 0.5), limiting the ability of Hainan gibbons to move between forest patches. The results of this study indicate that the availability of suitable habitat in Bawangling is insufficient to allow for future Hainan gibbon population growth. Therefore, immediate action must be taken to restore, reforest, and establish ecological corridors to reconnect areas of suitable habitat for these critically endangered gibbons. [ABSTRACT FROM AUTHOR]

This paper proposes a novel single‐feed filtering dielectric resonator antenna (FDRA) using fusion design method and the microstrip‐slot coupled feeding structure. Two pairs of slotlines are elaborately designed and perpendicularly loaded on the coupling slot to provide two radiation nulls at the edges of the passband. Therefore, a compact DRA with a quasi‐elliptic function bandpass response is constructed without extra filter circuits. Furthermore, two radiation nulls can be individually controlled through changing the length of the corresponding slotlines. For proving the effectiveness of the design, a prototype FDRA operation at 3.45 GHz is fabricated and measured. The measured results show that the peak realized gain is 5.84 dBi and the ‐10dB impedance bandwidth is 10.29% (3.29 ‐ 3.65 GHz). The proposed FDRA not only has good performance, but also has simple design. [ABSTRACT FROM AUTHOR]

A wideband bandpass filter (BPF) based on two dual‐mode stub‐loaded stepped‐impedance resonators (SLSIRs) with mixed electric and magnetic coupling (MEMC) is proposed. Magnetic coupling is realized by using a transmission line, open end‐coupling and inter‐digital‐coupling provide a weak and a strong electric coupling, respectively. Due to the canceling effect of MEMCs, together with its harmonic effect, four transmission zeros (TZs) aside the passband are created and the selectivity of the filter is therefore highly improved. To verify the proposed design, a four‐pole wideband BPF operating at 3.35 GHz with 3 dB fractional bandwidth (FBW) of 32.96% is designed, fabricated, and measured. The measured minimum insertion loss is 0.95 dB, and the passband return loss is better than 11 dB. [ABSTRACT FROM AUTHOR]

Aim In this article, we analysed two millennia of historical records and environmental information to reconstruct the past distribution and examine the current distribution of snub-nosed monkeys ( Rhinopithecus) in China. Location China. Methods We applied trend surface analysis ( TSA) to document patterns of range shifting in snub-nosed monkeys over time. Random forest was used to study the association between explanatory variables and changes in the distribution of snub-nosed monkeys over the past 2000 years. Results Our results showed that both the longitude and latitude of snub-nosed monkeys contracted from 0 to 2000 AD. We found that the integrated effects of human population size and changes in temperature in the Northern Hemisphere resulted in a westward and northward contraction of the snub-nosed monkey distributional range. However, the impact of fluctuating temperature was greatest during periods of low human population density (0-1200 AD), whereas from 1200 to 2000 AD, marked increases in human population size in China leading to extensive deforestation, agricultural expansion, hunting, logging and land terracing have had the greatest negative effects. Further analyses highlighted the fact that the rapid expansion of human population density in regions occupied by snub-nosed monkeys between 1700 and 2000 has resulted in the recent extirpation of this primate radiation in eastern, south-eastern and central China. Main conclusions We examined the interactive effects of human population growth, deforestation, agricultural expansion and climate variation on the past and current distribution of snub-nosed monkeys. Our data provide clear evidence that climate change, human population increase and human activities have differentially affected the viability and distribution of snub-nosed monkey populations over time. In particular, the marked expansion of the human population in China over the past 300 years has resulted in the extinction of Rhinopithecus populations across much of its range. [ABSTRACT FROM AUTHOR]

A modified quarter‐wavelength (λ/4) stepped‐impedance resonator (SIR) is proposed to design a miniature dual‐band bandpass filter (BPF). The proposed λ/4 SIR has two individually controllable resonances for constructing dual passbands. Moreover, two independent geometrical parameters are adopted to realise individual adjustment of the coupling strengths between two adjacent λ/4 SIRs at the dual passbands. As a result, both the centre frequencies and bandwidths of the two passbands of the filter can be individually designed. Furthermore, multiple transmission zeros are created by the introduced source‐load coupling, which improves highly the selectivity of both passbands. The dual‐band BPF is designed at 2.35 and 5.8 GHz, and its simulated and measured responses are presented and show good agreement. [ABSTRACT FROM AUTHOR]

In many primate species that form one-male breeding units (OMUs), the threat of a takeover by a bachelor male represents a major challenge to group stability and individual reproductive success. In the case of snub-nosed monkeys, which live in large multilevel or modular societies (MLS) comprising several OMUs that travel, feed and rest together and as well as one or more all male units (AMUs), the process by which rival males challenge resident OMU males for access to females is poorly understood. From September 2012 to October 2013, we recorded 48 cases in which rival males visited an OMU in a MLS of Yunnan snub-nosed monkeys ( Rhinopithecus bieti) inhabiting the Baimaxueshan National Nature Reserve, Yunnan Province, China. In 40 cases, rival males engaged in mild agonistic interactions (approaching, staring, teeth-baring and chasing) but failed to take over the group; we counted these visits as failed takeovers, recognizing that they may nevertheless allow rival males to assess the competitive ability of residents. During eight successful takeovers, however, there was severe physical aggression between challenging and resident males, with serious injuries to participants. We found that neither the number of adult and subadult females in an OMU, the number of non-pregnant, non-lactating adult females in an OMU, nor the rank of a resident male relative to other resident males in the MLS predicted which OMU a challenging male targeted for takeover. However, a resident male's rank significantly predicted whether takeover attempts were successful. Specifically, challenging males were more successful in displacing a lower-ranking resident male than a higher-ranking male. Given that a Yunnan snub-nosed monkey MLS may contain as many as 40 resident and 36 bachelor males, continued research is required to determine the set of factors that enable resident males to maintain high social rank and successfully defend their harems. Am. J. Primatol. 78:974-982, 2016. © 2016 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

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The highly polymorphic genes within the major histocompatibility complex (MHC) not only play a major role in immunity resistance, but also seem to provide hints for mate choice in some animal populations. In the present study we investigated MHC-related mate choice in a small natural population (group size 40-55 individuals) of a polygynous primate, the Sichuan snub-nosed monkey (Rhinopithecus roxellana). We found that there was no evidence either for MHC-disassortative mating, or for females to mate with males based on MHC heterozygosity or specific alleles. Nevertheless, of the 11 alleles identified, we found that the frequencies of 2 alleles, Rhro-DRB2 (P < 0.01) and Rhro-DRB5 (P < 0.05) were higher in offspring than in their parents. These findings suggest that MHC-DRB in this population of R. roxellana is unlikely to be associated with mating preferences. Limited female opportunities for mate choice are likely due, in part, to the harem breeding structure present in R. roxellana, and the relatively small number of resident adult males in our study band (N = 4-6). In addition, we suggest that differences in the frequency of particular alleles across generations may be linked to parasite resistance in a fluctuating environment; however, confirmation of this finding requires further study. [ABSTRACT FROM AUTHOR]

Although sex-biased dispersal has profound effects on the viability of small and isolated populations resulting from habitat change and anthropogenic disturbance, the direction and strength of sex-biased dispersal in the endangered Sichuan snub-nosed monkey ( Rhinopithexus roxellana) remains poorly understood. Here, we investigated dispersal patterns of R. roxellana using 15 polymorphic microsatellite loci. Using noninvasive methods we obtained 337 fecal samples from individuals residing in four multilevel troops that inhabit the Shennongjia Nature Reserve (SNR). Our study site contains an isolated population of approximately 1,000 Sichuan snub-nosed monkeys located in the easternmost distribution of the species' range. Our results indicated that the mean coefficient of relatedness among troop members was low (mean relatedness ± SE = 0.038 ± 0.025). However, the mean relatedness of monkeys residing in the same troop was significantly higher than the mean relatedness of monkeys belonging to different troops, suggesting that some members of the same troop were closely relatived. Sex-biased dispersal tests revealed that dispersal in R. roxellana was male-biased. Moreover, analysis of isolation-by-distance indicated that the correlation between pairwise genetic distance and geographical distance was positive for females, while it was negative for males. These data suggest that males tended to disperse further than females, although these values were not statistically significant. Considering previous field data collected on Sichuan snub-nosed monkeys from other sites, we suggest that mating competition among males and female mate choice represent the major causes of male-biased dispersal in R. roxellana. Am. J. Primatol. 76:72-83, 2014. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Extant colobines represent a predominantly arboreal primate radiation, but there are outliers such as some species of snub-nosed monkeys ( Rhinopithecus spp.) that utilize both arboreal and terrestrial substrates. We quantified the degree of terrestriality and the distribution of individuals across canopy levels, the extrinsic and intrinsic determinants and constraints of strata association as well as use of postures in relation to behavior and food sources in a wild population of Yunnan snub-nosed monkeys ( Rhinopithecus bieti) in the Samage Forest, China. The subjects spent 80.5% of the observation time in the trees and 19.5% on the ground. Ground use occurred most frequently in the context of travelling (61%) and less often in the context of feeding and resting (30% combined). Adult males frequented the ground significantly more often than other age-sex classes. Age-sex differences were also apparent in substrate preferences, which likely reflect body weight constraints. Adult males were significantly more associated with solid substrates and less with terminal branches than adult females and juveniles. Juveniles were seen more often on unstable ground (i.e. on thin and oblique branches) and in the upper canopy. Substrate use also varied with behavior: feeding was much more common in the upper stratum, outer canopy, on highly inclined and thin branches, as compared to resting. Severe weather also influenced canopy use in that tree crowns were used less often during periods of snowfall. The most frequently exhibited resting and feeding postures was sitting. Standing and suspensory postures were most often used in the context of feeding on lichens. [ABSTRACT FROM AUTHOR]

Sleeping site locations are important to free-ranging primate groups. Sites are strategically selected by primates so as to optimize security, comfort and foraging efficiency. Data were collected on the distribution of sleeping sites of the Yunnan snub-nosed monkey ( Rhinopithecus bieti) between Sep 2005 and Sep 2006 at Gehuaqing in Baimaxueshan Nature Reserve, China. We identified 54 sleeping sites, which were used 137 times during the study period. These sleeping sites were distributed throughout the monkey group's total home range. R. bieti preferred certain sleeping sites over others: 63% of the sleeping sites were used 2 or more times in 13 months. Groups reused locations in an unpredictable long-term pattern, but avoided using the same sleeping site on consecutive nights. To reduce the time and energetic costs of travel, monkeys preferred sleeping near commonly used feeding sites. We recorded 124 feeding sites in the home range, which were used 174 times. A total of 27 sleeping sites were also feeding sites, and all remaining sleeping sites were close to feeding sites. There was a positive correlation between the intensity of use of sleeping sites and feeding sites. The present study suggests that the availability and the location of immediate sources of food is a key factor in the choice of sleeping sites. [ABSTRACT FROM AUTHOR]

ABSTRACT A novel microstrip dual-band bandpass filter (BPF) with multimode square ring loaded resonators (SRLRs) is proposed in this article. The improved SRLR is loaded by a meander ring stub and a stepped-impedance resonator for compactness to realize the dual-band performances. Even- and odd-mode method is applied to explain mode splitting characteristics. Moreover, another mode in the second passband is generated by adding a half-wavelength U-shaped resonator. This resonator also introduces cross-coupling between feed lines so that an additional transmission zero is produced, which enhance the selectivity. The dual-band BPF operating at 2.4 and 3.5 GHz for WLAN and WIMAX applications is designed and fabricated. Measurement results agree well with the simulated results. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2692-2695, 2013 [ABSTRACT FROM AUTHOR]

This article examines the effect of ambient temperature, day length, weather conditions, and seasonality on daily path length (DPL) of a free-ranging group of Yunnan snub-nosed monkeys (Rhinopithecus bieti) using an auto-released GPS collar. Data were collected from December 17, 2003 to October 22, 2004 at Laojunshan in northwestern Yunnan province, China. The average DPL of the monkey group was 909±472 m (n=291), with the shortest distance being 180 m and the longest distance 3,626 m. Ambient temperature and day length were found to affect DPL. Both factors were positively correlated with DPL, which means that the monkey group traveled greater distances on longer and warmer days. At the study site, three distinct seasons were identified, and DPL did not vary significantly across these periods. The time of sunrise was not correlated with DPL. Nevertheless, we sometimes observed the group starting its daily trip later on cloudy days than on sunny days. Furthermore, weather conditions (e.g. rainy, cloudy, and sunny) did not influence the average DPL of the study group. Overall we found that the primary factors affecting DPL in R. bieti were day length and ambient temperature, especially daily highest temperature. Am. J. Primatol. 71:233–241, 2009. © 2008 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The golden monkey (Rhinopithecus roxellana) is one of the most endangered primate species due to its dramatically shrinking distribution during the past 400 years. Its populations are restricted to three isolated regions, Qinglin (QL), Sichuan/Gansu (SG), and Shennongjia (SNJ) in China. As with other snub-nosed monkeys in China and Vietnam, the biology and evolution of this species is still poorly known. To assess genetic differentiation and explore the relationships among populations of golden monkeys from different geographic locations, 379 bp of mitochondrial DNA control region (CR) hypervariable segment I (HVI) was studied from 60 individuals. Twelve haplotypes were identified from seven populations within the three regions. Haplotype diversity was high (0.845), whereas nucleotide diversity among all haplotypes was low (0.0331). The most recent common ancestor (TMRCA) among mtDNA haplotypes was estimated to have lived approximately 0.48–0.32 million years ago. None of the haplotypes is shared among any of the three regions. Phylogenetic analysis and AMOVA revealed clear and significant phylogeographic structure between the three regions. However, only SG contained haplotypes of the two main clades, indicating either incomplete random sorting of haplotypes or a complex history with phases of population subdivisions and merging of populations. The phylogeographic structure implies that R. roxellana should be regarded as separate management units (MUs) for each of the three regions. It is likely that recent phylogeographic history has shaped the pattern of genetic differentiation observed in the golden monkey and that its populations have suffered significant demographic fluctuation. Am. J. Primatol. 69:1195–1209, 2007. © 2007 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The reproduction of female red pandas under three different husbandry conditions (monogamy, polygamy, and polyandry) was studied at the Chengdu Research Base for Giant Panda Breeding, and Chengdu Zoological Park, China. We monitored the fecal steroid profiles of seven females by radioimmunoassay in order to understand how the different mating groupings affect the animals' reproductive success. Of the seven females studied, all gave birth except the one that was kept in the polyandrous group. Although fecal estradiol metabolites exhibited several peaks during estrus, only one coincided with mating behavior. Fecal progesterone metabolites did not display a sustained rise in the absence of mating behavior, even though estradiol displayed a peak of secretion. This suggests that the red panda may be an induced ovulator. During gestation, fecal progesterone metabolites were maintained at a comparatively high level, and were much higher than those of nonpregnant females. The female in the polyandrous group showed an abnormal estradiol metabolite profile, with a level that was four to five times higher than those of the females in the polygynous groupings. It was observed that this female always escaped and hid in the trees to avoid courtships with males, and did not give birth. This phenomenon suggests that polyandrous groupings may be unsuitable for successful reproduction in captivity. Zoo Biol 24:169-176, 2005. © 2005 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Male–male interactions in mixed‐sex groups of social mammals are typically characterized by a mix of hostility and affiliation, as a result of inherent conflicts over mating opportunities, and the costs and benefits of social alliances, co‐operative behaviors, and coalitionary defense. In species of nonhuman primates that form all‐male groups, it is still unclear how the tradeoffs between the benefits of forming an all‐male group and the cost of male–male competition in seeking mating opportunities with females in bisexual groups influence social cohesion in different seasons. Here, we used social network analysis to quantify the impact of reproductive seasonality on social cohesion and clique size of bachelor males residing in an all‐male unit (AMU) in wild black‐and‐white snub‐nosed monkeys (Rhinopithecus bieti). These primates are strict seasonal breeders and live in a modular social system composed of a number of one‐male units (OMUs) and an associated peripheral AMU. We found that the AMU social network had a significantly lower density, centralization, clustering coefficient, and smaller clique size during the mating season compared to the non‐mating period. However, aggression among AMU males during both mating and non‐mating periods was low. Our results suggest that network structure topology in male same‐sex social units is modulated by seasonal changes. Bachelor males engage in two types of competition to gain reproductive success: first, which is analogous to contest competition, in which bachelor males act aggressively and challenge OMU leader males in an attempt to take over an OMU; and second, which is more analogous to scramble competition, in which bachelor males avoid aggressive interactions and instead engage in sneaky copulations with fertile females. Our work adds to an understanding of the maintenance of all‐male groups in species that form a multilevel society. This paper: 1) found bachelor males maintain affiliation throughout the year; 2) found a less cohesive network of an all‐male unit during the mating season than non‐mating periods; 3) suggests scramble competition characterizes bachelor males. [ABSTRACT FROM AUTHOR]

Weather, predation, and social organization are hypothesized to influence sleeping habits of nonhuman primates at night. To investigate how the Yunnan snub-nosed monkey (Rhinopithecus bieti) prepares for and behaves during cold nights in their harsh alpine forest habitat (above 3,000 m), we studied the sleeping habits of the 171 one-male units (OMU) in one group for 12 months at Xiangguqing in the Baimaxueshan Nature Reserve, China. It took 20.2 min from the time the study group entered a sleeping site until they fell asleep. This duration was consistent over seasons. On average, sleeping time was 11.5 hr per night over the year. Seasonal mean lengths of sleeping time varied significantly, however, and ranged from 10 to 13 hr per night, correlating with night length. Two sleeping styles were distinguishable: solitary sleeping and huddled sleeping. That adult males in OMUs principally slept alone. This is likely to reflect night-time guarding behavior. Female-juvenile and female-infant dyadic huddles were the most prevalent sleeping unit (42% of all observed data), and the monkeys employed female-biased huddling during nocturnal sleep. Huddled sleeping group size showed significant seasonal variation, with the largest huddle (eight individuals) occurring in winter. Climate and social organization profoundly influence the nocturnal sleeping habits of R. bieti, while huddling behavior may help shield animals from cold nights and provide additional protection against predators., (© 2010 Wiley-Liss, Inc.)

Only a few primate species thrive in temperate regions characterized by relatively low temperature, low rainfall, low species diversity, high elevation, and especially an extended season of food scarcity during which they suffer from dietary stress. We present data of a case study of dietary strategies and fallback foods in snub-nosed monkeys (Rhinopithecus bieti) in the Samage Forest, Northwest Yunnan, PRC. The snub-nosed monkeys adjusted intake of plant food items corresponding with changes in the phenology of deciduous trees in the forest and specifically showed a strong preference for young leaves in spring. A non-plant food, lichens (Parmeliaceae), featured prominently in the diet throughout the year (annual representation in the diet was about 67%) and became the dominant food item in winter when palatable plant resources were scarce. Additional highly sought winter foods were frost-resistant fruits and winter buds of deciduous hardwoods. The snub-nosed monkeys' choice of lichens as a staple fallback food is likely because of their spatiotemporal consistency in occurrence, nutritional and energetic properties, and the ease with which they can be harvested. Using lichens is a way to mediate effects of seasonal dearth in palatable plant foods and ultimately a key survival strategy. The snub-nosed monkeys' fallback strategy affects various aspects of their biology, e.g., two- and three-dimensional range use and social organization. The higher abundance of lichens at higher altitudes explains the monkeys' tendency to occupy relatively high altitudes in winter despite the prevailing cold. As to social organization, the wide temporal and spatial availability of lichens strongly reduces the ecological costs of grouping, thus allowing for the formation of "super-groups." Usnea lichens, the snub-nosed monkeys' primary dietary component, are known to be highly susceptible to human-induced environmental changes such as air pollution, and a decline of this critical resource base could have devastating effects on the last remaining populations. Within the order Primates, lichenivory is a rare strategy and only found in a few species or populations inhabiting montane areas, i.e., Macaca sylvanus, Colobus angolensis, and Rhinopithecus roxellana. Other temperate-dwelling primates rely mainly on buds and bark as winter fallback foods.

The golden monkey (Rhinopithecus roxellana) is one of the most endangered primate species due to its dramatically shrinking distribution during the past 400 years. Its populations are restricted to three isolated regions, Qinglin (QL), Sichuan/Gansu (SG), and Shennongjia (SNJ) in China. As with other snub-nosed monkeys in China and Vietnam, the biology and evolution of this species is still poorly known. To assess genetic differentiation and explore the relationships among populations of golden monkeys from different geographic locations, 379 bp of mitochondrial DNA control region (CR) hypervariable segment I (HVI) was studied from 60 individuals. Twelve haplotypes were identified from seven populations within the three regions. Haplotype diversity was high (0.845), whereas nucleotide diversity among all haplotypes was low (0.0331). The most recent common ancestor (TMRCA) among mtDNA haplotypes was estimated to have lived approximately 0.48-0.32 million years ago. None of the haplotypes is shared among any of the three regions. Phylogenetic analysis and AMOVA revealed clear and significant phylogeographic structure between the three regions. However, only SG contained haplotypes of the two main clades, indicating either incomplete random sorting of haplotypes or a complex history with phases of population subdivisions and merging of populations. The phylogeographic structure implies that R. roxellana should be regarded as separate management units (MUs) for each of the three regions. It is likely that recent phylogeographic history has shaped the pattern of genetic differentiation observed in the golden monkey and that its populations have suffered significant demographic fluctuation.