Nomascus Leucogenys Research Articles

Haplotype-phased genome assemblies and annotation of the northern white-cheeked gibbon (Nomascus leucogenys)

Nomascus leucogenys is a critically endangered species of small apes. Here, we sequenced and assembled the male genome of N. leucogenys, using PacBio and Hi-C datasets, with a particular focus on its Y-chromosome. The resulting high-quality haplotype-phased assemblies are at chromosome-scale, with scaffold/contig N50 values of 124.2/102.2 Mb for Haplotype 1 and 121.2/85.67 Mb for Haplotype 2. The assembled Y-chromosome spans 16.06 Mb. BUSCO assessment indicated completeness scores exceeding 95%. We predicted 18,925 protein-coding genes (23,783 mRNAs), including 58 genes on the Y-chromosome. Approximately 50% of the genome comprises repetitive elements. These comprehensive genome datasets will serve as a valuable resource for future studies on the genetics and protection of gibbons and improve our understanding on the evolution of Y-chromosome-related genes in primates.

Hormonal changes in northern white-cheeked gibbons (Nomascus leucogenys) after the death of a group member.

The small apes, gibbons and siamangs, are monogamous species with their social groups comprising of both parents and their offspring. Therefore, the loss of a member may elicit a stress response in the remaining members due to their strong bonds. Glucocorticoids (GCs) have been useful indicators of stress, but distinguishing between acute versus chronic stress may be limited when measuring these hormones alone. The adrenal hormone dehydroepiandrosterone-sulfate (DHEAS), a GC antagonist, has been implicated in the regulation of the stress response. Thus, the concomitant measurement of these hormones can help examine whether an event, such as the loss of a group member, elicited a stress response. In this brief report, we discuss the hormonal response of two zoo-housed northern white-cheeked gibbons (Nomascus leucogenys) (1 adolescent male and his mother) after the death of the adult male of the group. Baseline fecal samples were collected opportunistically from these two individuals 5months prior, and 3months following the death of their group member. A total of 25 samples were quantified for fecal GC metabolites (FGCMs) and DHEAS by enzyme immunoassay (EIA) to calculate the FGCMs:DHEAS ratio. Our results indicate an increase in FGCMs and FGCMs:DHEAS for the adolescent male, but not the adult female, following the death. Our findings suggest that the integration of FGCMs and DHEAS measurements can provide valuable information to interpret individual stress levels to the sudden change in the group's social structure.

ASSESSMENT OF ACUTE PHASE PROTEINS AND PROTEIN ELECTROPHORESIS IN HEALTHY GIBBONS (HYLOBATIDAE) IN MANAGED SETTINGS.

Acute phase proteins (APP) and protein electrophoresis (EPH) offer crucial insights into inflammation and overall health in various species. In this study, we validated serum amyloid A (SAA) and C-reactive protein (CRP) reagents for use with serum samples from gibbons (Hylobatidae, n = 50), spanning five species across four gibbon genera: eastern hoolock (Hoolock leuconedys), Javan (Hylobates moloch), pileated (Hylobates pileatus), siamang (Symphalangus syndactylus), and white-cheeked (Nomascus leucogenys). Preliminary reference intervals (n = 50) were calculated for SAA (1.8-48.1 mg/L), CRP (0.1-11.1 mg/L), and EPH via capillary zone electrophoresis, in healthy gibbons. Comparing clinically normal (n = 38) and abnormal (n = 12) individuals, significant differences were observed in the albumin/globulin ratio (P = 0.0003), prealbumin (P = 0.0345), and albumin (P = 0.0094), with abnormal individuals exhibiting statistically significantly higher γ-globulins (P = 0.0224), SAA (P = 0.0001), and CRP (P = 0.0003). Despite significant chromosomal rearrangements among different gibbon species, we found no statistically significant differences of SAA and CRP levels across species. However, some differences between species were observed in EPH fractions. This study presents the first report of the evaluation of APP and EPH in gibbons, underscoring the potential use of these biomarkers in gibbon health monitoring. Further research with larger sample sizes of both normal and abnormal gibbons is recommended to solidify the clinical utility of these biomarkers in these species.

Examining predictive meteorological variables in the singing behavior of northern white-cheeked gibbons (Nomascus leucogenys) in northern Lao PDR.

Considering the conservation attention needed to keep viable the few remaining wild populations of the Critically Endangered northern white-cheeked gibbon (Nomascus leucogenys), there has been a serious paucity of research undertaken for the species. To improve the effectiveness of surveys of this and other gibbon species, and ultimately their conservation, it is important to better understand the variables that affect their singing behavior-the feature that is currently used in most gibbon population surveys. We collected singing and meteorological data from 320 days, between October 2020 and March 2021, at 80 different locations, during an auditory presence/non-detection survey of N. leucogenys in northeastern Lao PDR. Songs were detected on 100 of the 320 days, a total of 154 song bouts. We analyzed the differences in song bout frequency, song bout timing (in relation to sunrise), and song bout length in relation to the meteorological variables of temperature, relative humidity, cloud cover, rain, fog, and wind. We found song bout frequency to be significantly greater on mornings with cloud cover (as a function of improved detection), on mornings without fog, on mornings without rain, and on warmer mornings. We found song bouts to start significantly earlier on mornings without fog and on warmer mornings when fog was present. Finally, we found song bouts lasted longer on mornings with fog and on warmer mornings. We did not find any significant relationships with relative humidity or wind. These patterns fit with prior research on behavioral responses of gibbons to weather and improve the understanding of gibbon vocal behavior to better prepare researchers for designing auditory surveys of Nomascus and other gibbon species.

Current and suitable habitat of the Critically endangered Northern white-cheeked gibbon (Nomascus leucogenys) in Lao PDR

Current and suitable habitat of the Critically endangered Northern white-cheeked gibbon (Nomascus leucogenys) in Lao PDR

Estimation of population and threats of Northern White-cheeked Gibbon (Nomascus leucogenys) in Phou Khao Khouay National Biodiversity Conservation Area, Lao PDR

Estimation of population and threats of Northern White-cheeked Gibbon (Nomascus leucogenys) in Phou Khao Khouay National Biodiversity Conservation Area, Lao PDR

Isochronous singing in 3 crested gibbon species (Nomascus spp.).

The search for common characteristics between the musical abilities of humans and other animal species is still taking its first steps. One of the most promising aspects from a comparative point of view is the analysis of rhythmic components, which are crucial features of human communicative performance but also well-identifiable patterns in the vocal displays of other species. Therefore, the study of rhythm is becoming essential to understand the mechanisms of singing behavior and the evolution of human communication. Recent findings provided evidence that particular rhythmic structures occur in human music and some singing animal species, such as birds and rock hyraxes, but only 2 species of nonhuman primates have been investigated so far (Indri indri and Hylobates lar). Therefore, our study aims to consistently broaden the list of species studied regarding the presence of rhythmic categories. We investigated the temporal organization in the singing of 3 species of crested gibbons (Nomascus gabriellae, Nomascus leucogenys, and Nomascus siki) and found that the most prominent rhythmic category was isochrony. Moreover, we found slight variation in songs' tempo among species, with N. gabriellae and N. siki singing with a temporal pattern involving a gradually increasing tempo (a musical accelerando), and N. leucogenys with a more regular pattern. Here, we show how the prominence of a peak at the isochrony establishes itself as a shared characteristic in the small apes considered so far.

The impact of climate change and human activities over the past 2000 years has increased the spatial-temporal extinction rate of gibbons

Climate change and human activities can drive extinction risk by limiting and fragmenting species distributions, and reducing effective population size. However, it is difficult to quantify the degree to which species decline is due to climate change, human activities, or a combination of both factors. Here, we present data on changes in gibbon distribution over the past 2000 years, along with expected patterns of climate change to predict future changes in gibbon distribution and population survival. We found that local gibbon extinction rates and range contraction in China increased significantly over the past 2000 years, from 0 % between 0 and 800 CE to 5 % from 801 to 1700 CE, to 30 % from 1701 to 1950 CE, and 71 % from 1951 to 2020 CE. Based on genetic evidence, the effective population size of the northern white–cheeked gibbon (Nomascus leucogenys) in China decreased by 8 % between 0 and 800 CE, 15 % between 801 and 1700 CE, 48 % between 1701 and 1950 CE, and 100 % between 1951 and 2020 CE. In addition, over the past 2000 years, China's human population density increased from 17.56 individuals/km2 to 60.68 individuals/km2. Human population increase was positively correlated with the conversion of forested habitats into anthropogenic landscapes, and this was found to be a more significant factor than climate change in driving gibbon range decline and population extinction. Climate models predict that by the year 2050, the availability of suitable habitat for three gibbon species in China is expected to decrease by 23 %–91 %. Our results indicate that unless immediate and effective action is taken to protect gibbons and their habitats from the deleterious effects of climate change and a large human population, all species of gibbons in China will likely go extinction by the end of the century.

Changes in suitable habitat for the critically endangered Northern white-cheeked gibbon (Nomascus leucogenys) in the Western Nghe An Biosphere Reserve, Vietnam: Implication for conservation

Several recent studies have highlighted that change in land use and land cover (LULC) is the main threat causing the decline and extinction of certain species. Gibbons (Hylobatidae) could be excellent examples, on account of their potential for extinction in the near future under the effects of LULC changes due to their particular ecological traits. This study aims to model the current suitable habitat of the Northern white-cheeked gibbon (Nomascus leucogenys (Ogilby, 1840)) in the Western Nghe An Biosphere Reserve (BR), Vietnam and assess the changes in its suitable habitat following the changes in LULC from 1990 to 2020. The maximum entropy approach (MaxEnt) was used to predict the suitable habitat of the gibbon using its occurrence localities and environmental predictors. The model analysis showed that the “Distance to Agriculture” variable had the strongest impact on the gibbons’ suitable habitat. Our results predicted the present suitable habitat of the gibbon species at approximately 4,022.42 km2 (30.95% of the overall BR area) in three spatially separated areas inside the Western Nghe An BR. Furthermore, the suitable habitat areas of the gibbon in 1990, 2000, and 2010 were projected at roughly 4,347.68 km2, 4,324.97 km2, and 2,750.21 km2, respectively, following a decreasing trend from 1990 to 2010, but a gradual increase between 2010 and 2020. The suitable habitat of the gibbon inside three core protected areas (Pu Mat National Park, Pu Huong, and Pu Hoat Nature Reserves) showed a continually increasing trend from 1990 to 2020. Our results highlighted the influence of LULC changes and the role of the protected area network in gibbon conservation. The information from the study provides a quantitative baseline for the future conservation of the critically endangered gibbon in the Western Nghe An BR.

A high-resolution map of small-scale inversions in the gibbon genome.

Gibbons are the most speciose family of living apes, characterized by a diverse chromosome number and rapid rate of large-scale rearrangements. Here we performed single-cell template strand sequencing (Strand-seq), molecular cytogenetics, and deep in silico analysis of a southern white-cheeked gibbon genome, providing the first comprehensive map of 238 previously hidden small-scale inversions. We determined that more than half are gibbon specific, at least fivefold higher than shown for other primate lineage-specific inversions, with a significantly high number of small heterozygous inversions, suggesting that accelerated evolution of inversions may have played a role in the high sympatric diversity of gibbons. Although the precise mechanisms underlying these inversions are not yet understood, it is clear that segmental duplication-mediated NAHR only accounts for a small fraction of events. Several genomic features, including gene density and repeat (e.g., LINE-1) content, might render these regions more break-prone and susceptible to inversion formation. In the attempt to characterize interspecific variation between southern and northern white-cheeked gibbons, we identify several large assembly errors in the current GGSC Nleu3.0/nomLeu3 reference genome comprising more than 49 megabases of DNA. Finally, we provide a list of 182 candidate genes potentially involved in gibbon diversification and speciation.

Conservation planning on China's borders with Myanmar, Laos, and Vietnam.

Transboundary conservation is playing an increasingly important role in maintaining ecosystem integrity and halting biodiversity loss caused by anthropogenic activities. However, lack of information on species distributions in transboundary regions and understanding of the threats in these areas impairs conservation. We developed a spatial conservation plan for the transboundary areas between Yunnan province, southwestern China, and neighboring Myanmar, Laos, and Vietnam in the Indo‐Burma biodiversity hotspot. To identify priority areas for conservation and restoration, we determined species distribution patterns and recent land‐use changes and examined the spatiotemporal dynamics of the connected natural forest, which supports most species. We assessed connectivity with equivalent connected area (ECA), which is the amount of reachable habitat for a species. An ECA incorporates the presence of habitat in a patch and the amount of habitat in other patches within dispersal distance. We analyzed 197,845 locality records from specimen collections and monographs for 21,004 plant and vertebrate species. The region of Yunnan immediately adjacent to the international borders had the highest species richness, with 61% of recorded species and 56% of threatened vertebrates, which suggests high conservation value. Satellite imagery showed the area of natural forest in the border zone declined by 5.2% (13,255 km2) from 1995 to 2018 and monoculture plantations increased 92.4%, shrubland 10.1%, and other cropland 6.2%. The resulting decline in connected natural forest reduced the amount of habitat, especially for forest specialists with limited dispersal abilities. The most severe decline in connectivity was along the Sino‐Vietnamese border. Many priority areas straddle international boundaries, indicating demand and potential for establishing transboundary protected areas. Our results illustrate the importance of bi‐ and multilateral cooperation to protect biodiversity in this region and provide guidance for future conservation planning and practice.

Hormones and Color Change in Female White-Cheeked Gibbons, Nomascus leucogenys

Sexual dichromatism is a well-studied form of sexual dimorphism and is evident in a variety of taxa. Gibbons in the genera Nomascus and Hoolock are sexually dichromatic, with adult females having light or blonde pelage while adult males are black. All infants are born blonde, and all turn black at ca. 1–1.5 yr of age. Females then undergo a second pelage color change some time between the ages of 5 and 9 yr, when they attain their adult, blonde pelage. Here, we examine patterns of reproductive hormones (progesterone and estrone-3-glucuronide, or E1G) in 10 zoo-housed female white-cheeked gibbons (Nomascus leucogenys) during the maturation period. Females ranged in age from 2.8 to 9.8 yr during the time of sample collection. We used photographs of each female to estimate color on a five-point scale. We found a significant relationship between color and mean concentration of E1G (r = 0.69) but not between age and color (r = 0.16), or progesterone and color (r = 0.37). These results suggest a correlation between estrogen and color change in white-cheeked gibbons.

Reproductive Parameters of Captive Female Northern White-Cheeked (Nomascus leucogenys) and Yellow-Cheeked (Nomascus gabriellae) Gibbons

Reproductive and life-history characteristics, such as age at first reproduction, interbirth interval (IBI), sex ratio of newborns, and infant mortality, are crucial for assessing the population dynamics and survival of threatened species. There are no longitudinal data on the life histories of the threatened northern white-cheeked gibbons (Nomascus leucogenys) and yellow-cheeked gibbons (Nomascus gabriellae). Here, we examine the reproductive parameters of these species in 19 Chinese zoos. Some of these captive individuals may be hybrids of N. leucogenys × N. gabriellae, but it is not possible to distinguish these hybrids from the parent species based on morphological characteristics. Thus, in this study we identified individuals to species level from the zoos’ archives. Based on breeding records, 46 infants were born to 14 female northern white-cheeked gibbons from 2000 to 2019 and 89 infants to 29 female yellow-cheeked gibbons from 1995 to 2018. The mean age at first reproduction was 10.1 ± SD 2.4 yr for northern white-cheeked gibbons and 10.0 ± SD 3.1 yr for yellow-cheeked gibbons. The mean IBI was 32.8 ± SD 11.7 mo for northern white-cheeked gibbons and 27.2 ± SD 14.8 mo for yellow-cheeked gibbons. There was no significant effect of parity on IBI in northern white-cheeked gibbons, but primiparous mothers had a significantly longer IBI than multiparous mothers in yellow-cheeked gibbons. There was no significant difference in infant mortality between primiparous and multiparous mothers for either species. The sex ratio of newborns did not deviate significantly from 1:1 for either species. Infant mortality was 13% for northern white-cheeked gibbons and 12% for yellow-cheeked gibbons. Infant death reduced the IBI by 19 mo in northern white-cheeked gibbons and 10 mo in yellow-cheeked gibbons. Our data suggest that the intrinsic reproduction rate is very low in these gibbons and that wild populations may continue to decline without suitable conservation intervention.

How Target Animacy Affects Manual Laterality in Hylobatidae: The First Evidence in Northern White-Cheeked Gibbons (Nomascus leucogenys)

Our study presents the first evidence on how target animacy impacts on manual laterality in the Hylobatidae and contributes to filling the knowledge gap between monkeys and great apes in primate evolution of emotional lateralization. Eleven captive individuals of northern white-cheeked gibbons (Nomascus leucogenys) were chosen as focal subjects. There were significantly more ambipreferent individuals than left/right-handed individuals for both inanimate (χ²(1, n = 11) = 7.364, p = 0.007) and animate (χ²(1, n = 11) = 4.455, p = 0.035) targets, meaning no significant group-level hand preference. The right hand was more frequently used than the left hand for inanimate targets whereas the left hand was more frequently used than the right hand for animate targets, although the interaction between target animacy and hand use was not significant (proportion: F1, 10 = 0.283, p = 0.607; rate: F1, 10 = 0.228, p = 0.643). Our findings in N. leucogenys could not fully support either the tool use theory or the right hemisphere hypothesis.

Identifying priority areas for the conservation of the Critically Endangered northern white-cheeked gibbonNomascus leucogenysin northern Lao

AbstractAll gibbon species are declining throughout South and South-east Asia because of habitat loss and human activities such as hunting. Lao still contains a relatively large area of forest habitat suitable for gibbons, but their status in the country remains poorly known. Here we present the first density estimate of the Critically Endangered northern white-cheeked gibbonNomascus leucogenysin Nam Et-Phou Louey National Protected Area, northern Lao. We conducted gibbon surveys using an auditory sampling technique during May–August 2014 and May 2015, at 40 sites, covering 125.6 km2. We applied N-mixture models to analyse group counts, investigating which landscape and human disturbance covariates influenced the spatial variation of gibbon abundance across the study area. We estimated the average gibbon density to be 0.4 groups/km2. Gibbon density was higher in mixed deciduous forest (0.74 groups/km2) than in evergreen forest (0.09 groups/km2), which could be a result of long-term hunting in evergreen forest areas. Thus, future gibbon protection plans should consider not only evergreen forest as priority habitat, but also deciduous forest, which tends to receive less attention in conservation planning. We also highlight key areas containing gibbons where law enforcement patrols should be focussed, to limit threats such as poaching. Future forest management plans should aim to maximize the size and connectivity of suitable gibbon habitat, to enable exchange between subpopulations.

Fur color change and hormonal development in captive females of northern white-cheeked (Nomascus leucogenys) and buff-cheeked (Nomascus gabriellae) gibbons

Gibbons of the genus Nomascus exhibit strong sexual dichromatism in fur color. Change of fur color in sub-adult wild Nomascus females is associated with the onset of puberty and the time of their dispersal. The variability in fur change may be influenced by social factors. In this study, we determined whether in captive females of crested gibbons begin reproductive maturity prior to dispersing and with association to their fur color. We collected 287 fecal extracts to analyze pregnandiol -3- glucuronide and 17β estradiol profiles of 4 sub-adult females (Nomascus leucogenys and Nomascus gabriellae) and 183 samples from their mothers, using enzyme immunoassays. The sub-adult females were monitored from 4 years of age. Their hormone profiles showed the onset of ovulatory cycling between 4.6 and 5.8 years. Based on the information about the estrogen influence to the secondary sex characteristic (fur color of female) the positive link between estrogen concentration and age of the sub-adult females was found. However, the amount of the estrogen can apparently be influenced by the presence of mother. If the mother was presented, the level of estrogen was higher than if the mother was missing. Our findings suggest that the probability of changing to beige fur color by the sub-adult females increased with increased age and if they were without mother. This initial study presents the maternal influence as a possible social factor affecting the fur color change of female offspring.

Postural effect on manual laterality during grooming in northern white-cheeked gibbons (Nomascus leucogenys).

Investigations on manual laterality in non-human primates can help clarify human evolutionary origins of hand preference and cerebral cognition. Although body posture can influence primate hand preference, investigations on how posture affects hylobatid manual laterality are still in their infancy. This study focused on how spontaneous bipedal behavioral tasks affect hand preference in Hylobatidae. Ten captive northern white-cheeked gibbons (Nomascus leucogenys) were chosen as focal subjects. Unimanual grooming during sitting posture and supported bipedal posture were applied as behavioral tasks. The gibbons displayed a modest tendency on left-hand preference during sitting posture and right-hand preference during supported bipedal posture, although no group-level hand preference was detected for either posture. From the sitting to supported bipedal posture, 70% of individuals displayed different degrees of right-side deviation trends. The strength of manual laterality in the supported bipedal posture was higher than that in the sitting posture. We found significant sex differences in manual laterality during supported bipedal posture but not during sitting posture. Thus, to a certain degree, bipedal posture in N. leucogenys facilitates stronger hand preference, elicits a rightward trend in manual laterality, and produces sex-specific hand preference.

Genetic characterisation and phylogenetic status of whipworms (Trichuris spp.) from captive non-human primates in China, determined by nuclear and mitochondrial sequencing

BackgroundWhipworms (Nematoda: Trichuridae), among the most common soil-transmitted helminths (STHs), can cause the socioeconomically important disease trichuriasis in various mammalian hosts including humans and non-human primates. For many years, Trichuris from non-human primates has been assigned to the same species as the one infecting humans Trichuris trichiura. More recently, several molecular reports challenged this assumption following recognition of a Trichuris species complex observed in humans and non-human primates. A refined concept for species limits within Trichuris contributes to an understanding of diversity and the potential (zoonotic) transmission among humans and non-human primates. In this study, we expanded previous investigations by exploring the diversity of Trichuris among eight primates including three Asian autochthonous species (i.e. Rhinopithecus roxellana, Rhinopithecus bieti and Nomascus leucogenys). Species-level identification, whether novel or assignable to known lineages of Trichuris, was based on analyses of nuclear internal transcribed spacers (ITS) and mitochondrial cytochrome c oxidase subunit 1 (cox1) genes.ResultsIn total, seven genetically distinct subgroups of whipworms were determined to be present among the primates sampled. Most Trichuris lineages, including Subgroups 1, 1’, 3, 5 and 6, showed a broad host range and were not restricted to particular primate species; in addition to T. trichiura, a complex of Trichuris species was shown infecting primates. Furthermore, it was assumed that Trichuris spp. from either N. leucogenys and P. hamadryas or R. roxellana and R. bieti, respectively, were conspecific. Each pair was indicated to be a discrete lineage of Trichuris, designated, respectively, as Subgroups 1 or 1’ and 2, based on integrated genetic and phylogenetic evidence.ConclusionThese results emphasise that the taxonomy and genetic variations of Trichuris are more complicated than previously acknowledged. These cumulative molecular and phylogenetic data provide a better understanding of the taxonomy, genetics and evolutionary biology of the whipworms.

Retained duplications and deletions of CYP2C genes among primates

The human genome encodes about 60 functional enzymes of the cytochrome P450 superfamily, including four functional enzymes of the cytochrome P450 2C (CYP2C) subfamily. These enzymes have been shown to metabolize drugs and xenobiotic toxins, such as those in the diet, and are therefore of great importance for biomedical research and applications. While the pharmacology of P450 enzymes has been studied extensively, our understanding of molecular evolution of this gene family is incomplete, in part because a great variation exists in the number of CYP2C homologs across genomes. In humans, the enzymes encoded by these genes are responsible for the metabolism of more than 20% of clinical drugs, but this is not the naturalistic function of these enzymes, which is the metabolism of xenobiotics such as plant secondary metabolites. In this paper, we sought to correlate evolutionary relationships among primate CYP2C genes with known dietary profiles from these species, testing the hypothesis that these genes have evolved under the pressure of dietary toxins. Aside from a small number of deeply divergent genes, primate CYP2C paralogs form three separate clades: CYP2C18, CYP2C9/CYP2C19, and CYP2C8/CYP2C20. Our results showed that the CYP2C18 gene has been separately lost in Nomascus leucogenys and the Panini genomes, and there is no evidence that this gene has been under any positive selection among primates. While CYP2C20 has been retained in cercopithecoids, orthologous loci were separately lost in platyrrhines and hominoids. Notably, nine codons exhibited signature of positive selection. Finally, the CYP2C19 locus was duplicated in basal catarrhines, resulting in the birth of CYP2C9; but the ancestral locus was only retained in hominoid taxa. Overall, our findings support the hypothesis that primate CYP2C genes have evolved in response to selective pressures provided by dietary toxins, although not all gene clusters have evolved in the same manner. Our results may indicate an evolutionarily deep difference in ecology or physiology among higher-order primate taxa.

Correction: Multilocus genotyping of Giardia duodenalis in captive non-human primates in Sichuan and Guizhou provinces, Southwestern China.

[This corrects the article DOI: 10.1371/journal.pone.0184913.].