Dental Variation Among Asian Colobines, with Specific Reference to the Macaques on the Same Continent

In order to discern dental morphometric variations among the Asian colobines, residuals of the colobines, derived from allometric baselines formed by the Asian macaques （Macaca）, were analyzed with Principal Components Analysis and Euclidean Distances. Results indicated that the widely accepted view that the colobines possess relatively smaller front teeth than the macaques is only the case for the first incisors. The colobines show relatively smaller molars than the macaques. Such profiles may be related to the differences in dietary preferences between the two major groups of the Asian Old World monkeys. The magnitude of such differences is not as great as usullay assumed for the two groups that contain both African and Asian taxa. In other words, the two Asian cercopithecoid groups may have homogenously been shaped by the tectonic modifications and climate alterations in the past five million years. There exist marked differences among the Asian colobines when each of the genera is compared with macaques; the dental profile reflects not only the variation in geographic distribution but also in phylogenetic divergence. Thus, the snub-nosed monkeys （Rhinopithecus） and the gray langurs （Semnopithecus） are characterized by relatively larger molars than the other colobines - larger even than those of the macaques. The differences among Asian colobines, depicted by Euclidean Distances, seems to reflect the relationship of the phylogeny and evolution between colobines and cercopithecines.

Substrate use and postural behavior in free-ranging snub-nosed monkeys(Rhinopithecus bieti)in Yunnan

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.

Isolation of microsatellite loci and reliable genotyping using noninvasive samples of a critically endangered primate, Trachypithecus leucocephalus

Genetic information can be critical in identifying conservation priorities and developing conservation strategies.There is an urgent need for noninvasive genetic tools to study the wild populations of Asian colobine monkeys.The majority of these species are threatened with habitat destruction,population reduction and even extinction,but generally lack information on their genetic diversity and population structure.Genetic sampling and tissue collection have been scarce in these species owing to strict regulations on manipulation of endangered species,and the difficulties and risks associated with capturing these arboreal and fast-moving monkeys in the challeng­ing environments that they inhabit.These difficulties have hindered the development of molecular genetic mark­ers,which are usually derived from tissues or blood.In this study,we present a method for de novo microsatel­lite isolation and genotyping using DNA from noninvasive origins of a critically endangered Asian colobine,the white-headed langur(Trachypithecus leucocephalus).Genomic DNA isolated from hair was shown to be suf­ficient for microsatellite enrichment and isolation,with similar isolation efficiencies as from tissue DNA.We identified and characterized 20 polymorphic microsatellite loci,and evaluated their amplification success and genotyping reliability with 86 field-collected fecal samples.These results show that this panel of loci can pro­duce reliable genotypes from fecal samples,and represent a useful tool for noninvasive investigation of genetic structure,individual identification and kinship assessment in this highly endangered species.Our approach can be applied to conservation genetic studies of other wild species that lack sequence information and tissue sam­ples.