Pygathrix Research Articles

Adaptive evolution of a duplicated pancreatic ribonuclease gene in a leaf-eating monkey.

Although the complete genome sequences of over 50 representative species have revealed the many duplicated genes in all three domains of life, the roles of gene duplication in organismal adaptation and biodiversity are poorly understood. In addition, the evolutionary forces behind the functional divergence of duplicated genes are often unknown, leading to disagreement on the relative importance of positive Darwinian selection versus relaxation of functional constraints in this process. The methodology of earlier studies relied largely on DNA sequence analysis but lacked functional assays of duplicated genes, frequently generating contentious results. Here we use both computational and experimental approaches to address these questions in a study of the pancreatic ribonuclease gene (RNASE1) and its duplicate gene (RNASE1B) in a leaf-eating colobine monkey, douc langur. We show that RNASE1B has evolved rapidly under positive selection for enhanced ribonucleolytic activity in an altered microenvironment, a response to increased demands for the enzyme for digesting bacterial RNA. At the same time, the ability to degrade double-stranded RNA, a non-digestive activity characteristic of primate RNASE1, has been lost in RNASE1B, indicating functional specialization and relaxation of purifying selection. Our findings demonstrate the contribution of gene duplication to organismal adaptation and show the power of combining sequence analysis and functional assays in delineating the molecular basis of adaptive evolution.

Cranial morphology of the golden monkey (Rhinopithecus) and douc langur (Pygathrix nemaeus)

Because they have been less studied than most other non-human primates (partly due to the difficulties in accessing their habitat) the origins and phylogenetic relationships ofR. roxellana andR. bieti are controversial. These controversies may be clarified to some degree by adding information on the cranium. To this end, ten cranial dimensions analysed morphometrically here provide data about cranial differences among species of the genusRhinopithecus, and between species ofRhinopithecus andPygathrix nemaeus. Though more similar to each other than to any others in the same genus, the results show a significant separation betweenR. roxellana andR. bieti to the degree that they may be regarded as two different species. This confirms the conclusions of prior studies of external features, qualitative morphological characteristics and biochemical evidence (Yeet al, 1987; Zhang and Ryder, 1995; Jablonski, 1998; Penget al., 1988). The differences between these two species are mainly size-related, being highly correlated with cranial length. Other differences, probably non-size related shape differences, however, are highly correlated with cranial width. Sexual dimorphism plays a part in these findings. In relation to the other species, however, the results show that the Vietnam golden monkey (R. avunculus) has closer craniometric relationships with the douc langur (Pygathrix nemaeus) rather than with the three Chinese golden monkey species. Of these, the Gouzhou species (R. brelichi) shares more similarity withR. avunculus and is more separate fromRhinopithecus roxellana and R. bieti. The smaller differentiation between the two latter species could be due to their more recent separation following the dramatic elevation of Qinghai-Tibetan Plateau after the Middle Pleistocene.

The Seasonal Diet of the Sichuan Snub-Nosed Monkey (Pygathrix roxellana) in Shennongjia Nature Reserve, China

The Seasonal Diet of the Sichuan Snub-Nosed Monkey (Pygathrix roxellana) in Shennongjia Nature Reserve, China

Status and Conservation of Douc Langurs ( Pygathrix nemaeus ) in Laos

A recent systematic survey program of protected areas in Laos documented douc langurs (Pygathrix nemaeus) widely between 14°25′N and 18°38′N. Their precise northern limit is unclear as security constraints prevented survey there, but the species is unlikely to occur in Laos north of 20°. All our records are of the nominate, red-shanked form, P. n. nemaeus, though in the far south, greatly reduced red on the legs suggests intergradation with another form. Our records are overwhelmingly from evergreen or semievergreen forest and from a wide altitudinal range (200–1600 m). In most sites habitat was little degraded, but whether this reflects choice for such habitats, or the generally lower hunting pressure within them, is unclear. The largest population occurs over 3000 km 2 of the Nam Theun basin and surroundings, encompassing the protected areas of Nakai-Nam Theun, Hin Namno and the proposed Nam Theun Extension. This is the most important population of red-shanked langurs in the world. Laos supports globally the vast majority of their conservable population. Douc langurs are threatened in Laos by habitat fragmentation increasing their vulnerability to the existing high hunting levels. They are a favored target for local consumption and for local and Vietnamese hunters and traders. Protective measures should center around implementing habitat conservation and antihunting measures in the recently-declared National Biodiversity Conservation Areas. A recent government initiative to reduce gun use in rural areas is likely to have a strong positive effect on the population. The best protection for some time will remain the inaccessibility of their habitat. Accordingly, road-building into remote forest and piecemeal clearance at its edges should thus be minimized. Cross-border attention should be given to wildlife trading, including measures to reduce market demand.

Husbandry and breeding of Douc langurs Pygathrix nemaeus nemaeus at Cologne Zoo

In 1968 Cologne Zoo obtained 2.1 Douc langurs Pygathrix nemaeus nemaeus. In 1969 an additional 0.2 animals were imported and in 1990 a ♂ from Bekesbourne UK was introduced to infuse new genetic material into the collection. Since 1970 24 Douc langurs have been born at the Zoo where, at time of writing, 5.6 animals are maintained. Details on husbandry, feeding, health, social behaviour and reproduction are given. The hand‐rearing of 1.1 and reintroduction of 0.1 Douc langurs into a social group are described.

The phyletic position and systematics of the douc langurs of Southeast Asia.

In recent years, two major questions concerning the phyletic relationships and systematic position of the douc langurs have arisen. These concern, firstly, the taxonomic level at which the doucs as a group should be distinguished and, secondly, the number of taxa of doucs that should be recognized. It has recently been demonstrated on the basis of an exhaustive phylogenetic analysis that the doucs are generically distinct from the snub-nosed langurs and that they should be referred to as species of Pygathrix and Rhinopithecus, respectively [Jablonski and Peng, Folia Primatologica 60:36-55, 1993]. The present investigation was directed toward testing this conclusion using an expanded data set and a different method of character coding, and toward addressing the question as to the number of species or subspecies of doucs that should be recognized. A wide variety of data from large samples of doucs (n = 38), snub-nosed langurs (n = 53), and an out group (macaques; n = 191) were assembled, coded, and analyzed using an interactive computerized program for phylogenetic analysis. The specimens of Pygathrix examined included skeletal specimens, skins, and, when possible, living animals representing the three recognized taxa of doucs, nemaeus nigripes, and moi. The data base for the study comprised 178 characters, including measurements of skeletal specimens (98 characters), qualitative (presence or absence) morphological features (36 characters), characteristics of the pelage (39 characters), and 5 miscellaneous characters. The conclusions of the study were that 1) as a group, the taxa of Pygathrix preserved a larger number of primitive features for the Pygathrix-Rhino-pithecus clade than did the taxa of Rhinopithecus; 2) the taxa of Pygathrix were less different from one another than are the species of Rhinopithecus were from one another; 3) the subspecies Pygathrix nemaeus moi Kloss, 1926 be synonymized with Pygathrix nemaeus nigripes, as suggested by Napier [Catalogue of Primates in the British Museum (Natural History) and Elsewhere in the British Isles. Port III Family Cercopithecidae, Sub-Family Colobinae. London, 1985]; 4) the extant doucs were best recognized as two subspecies, P. nemaeus nemaeus for the red-shanked douc and P. nemaeus nigripes for the black-shanked douc; and 5) the phylogeny of the doucs and snub-nosed langurs proposed by Jablonski and Peng[op cit.,1993] was found to be robust. © 1995 Wiley-Liss, Inc.

Threatened primates in southern Vietnam

Vietnam's exceptionally rich fauna is threatened by habitat loss and hunting. Although a system of protected areas has recently been developed, many of the sites selected are subject to human encroachment, hunting pressure and other forms of exploitation. Other protected areas may be too small to hold viable populations of primates. Following faunal surveys of existing and proposed protected areas in Vietnam between 1988 and 1991, this paper documents the status of and identifies threats to three species of threatened primate: white-cheeked gibbon Hylobates leucogenys gabriellae, red-shanked douc langur Pygathrix nemaeus and blackshanked douc langur P. nigripes.

The Conservation of Nature in Viet Nam

Systematic efforts to conserve Viet Nam's natural resources began (in the North) in the early 1960s with the establishment of a 25,000-hectares' area, Cue Phuong National Park, south-west of Hanoi. Since the end of the Second Indochina war, Viet Nam's Ministry of Forestry has undertaken a comprehensive programme to restore forests that were destroyed or damaged in the fighting, to inventory forests and their resources, and to develop forest management for the economy and recreation of the Vietnamese people. The Ministry of Forestry's Institute of Forest Inventory and Planning is the agency carrying out these tasks; it employs about 5,000 people, including well-trained scientists.Before 1963, there were no regulations regarding hunting in Viet Nam. Now the Ministry of Forestry has a Department of Protection which attempts to regulate hunting of game, such as deer, Wild Pigs, Tigers, and Leopards. Many species of birds and mammals are now totally protected. These include two primates, the Indochina Gibbon and the Douc Langur, as well as three species of wild cattle, the Kouprey, Banteng, and Gaur. The Kouprey and the Javan Rhinoceros are classified as endangered species because only a few individuals are known to be still alive, at least in Viet Nam. Elephants are trapped and trained for commercial purposes and for capture of wild Elephants, while the wild herds are increasing owing to the war's end and the prevention of killing.

Endangered Species and Habitats of Viet Nam

This brief paper presents the information which we obtained in August 1980 on the habitats and endangered species of Viet Nam by interviewing scientists in both Hanoi and Ho Chi Minh City (Saigon). We did this with officials of the Department of Zoology of the University of Hanoi, of the Institute of Biology of the National Centre for Scientific Research, of the Technical Department of the Ministry of Forestry, and with others.We were informed that Hylobates concolor (Whitecheeked or Black Gibbon) appears to be found in sufficient numbers to hold its own, but that H. pileatus (Pileated Gibbon) has been extirpated from Viet Nam. Pygathrix nemaeus (Douc Langur) also appears to be in no immediate danger of extinction. Bos sauveli (Kouprey), however, is said to be down to less than a dozen individuals in Viet Nam, and so little hope remains for this species. Lophura imperialis (Imperial Pheasant) has become even more rare than formerly and is in grave danger of extinction. The conifer Pinus krempfii also seems headed for extinction.The coastal mangrove forest is the single most seriously disrupted habitat of Viet Nam. Some 40% of this highly productive ecosystem has been obliterated by military activities, and these war-obliterated areas are now largely covered by a low-growing, inferior vegetation or else have been converted to agriculture.It is recognized that a comprehensive survey of the endangered species of Viet Nam is an urgent requirement, and that there is a pressing need for additional nature reserves. Economic conditions, however, seem to make early action improbable in both cases.

Monitoring female reproductive status in the Douc langur at San Diego Zoo

Monitoring female reproductive status in the Douc langur at San Diego Zoo

Karyotype abnormalities in two primate species, Pygathrix nemaeus and Lemur coronatus.

The karyotypes of 7 douc langurs (Pygathrix nemaeus) and 3 crowned lemurs (Lemur coronatus) were examined. Abnormalities in 23.5% of the karyotypes of 1 male douc langur were associated with a history of fathering stillborns and abortuses (38%). Karyotype analysis of an apparently normal female lemur revealed three differing karyotypes, one normal and two abnormal.

Gestation and birth of a Douc langur at San Diego Zoo

Gestation and birth of a Douc langur at San Diego Zoo

L'écologie des forêts claires du Cambodge oriental

Preliminary survey of the large mammal fauna of the open Diptcrocarpous woodlands in Eastern Cambodja : Among the species observed by the author, two are included in the IUCN list of endangered Mammals, the Kouprey and the Douec langur. In the Phnom Prick Reserve 23 koupreys were censused in 1968. The Douc langur is still common ; contrary to what is the rule in other langurs, the Douc was always met in pairs during the dry season.