THE PHYLOGENETIC-RELATIONSHIPS AND CLASSIFICATION OF THE DOUCS AND SNUB-NOSED LANGURS OF CHINA AND VIETNAM

The taxonomy of the douc and snub-nosed langurs has changed several ti mes during the 20th century. The controversy over the systematic posit ion of these animals has been due in part to difficulties in studying them: both the doucs and the snub-nosed langurs are rare in the wild a nd are generally poorly represented in institutional collections. This review is based on a detailed examination of relatively large numbers of specimens of most of the species of langurs concerned. An attempt was made to draw upon as many types of information as were available i n order to make an assessment of the phyletic relationships between th e langur species under discussion. Toward this end, quantitative and q ualitative features of the skeleton, specific features of visceral ana tomy and characteristics of the pelage were utilized. The final data m atrix comprised 178 characters. The matrix was analyzed using the prog ram Hennig86. The results of the analysis support the following conclu sions: (1) that the douc and snub-nosed langurs are generically distin ct and should be referred to as species of Pygathrix and Rhinopithecus , respectively; (2) that the Tonkin snub-nosed langur be placed in its own subgenus as Rhinopithecus (Presbytiscus) avunculus and that the C hinese snub-nosed langur thus be placed in the subgenus Rhinopithecus (Rhinopithecus); (3) that four extant species of Rhinopithecus be reco gnized: R. (Rhinopithecus) roxellana Milne Edwards, 1870; R. (Rhinopit hecus) bieti Milne Edwards, 1897; R. (Rhinopithecus) brelichi Thomas, 1903, and R. (Presbytiscus) avunculus Dollman, 1912; (4) that the Chin ese snub-nosed langurs fall into northern and southern subgroups divid ed by the Yangtze river; (5) that R. lantianensis Hu and Qi, 1978, is a valid fossil species, and (6) the precise affinities and taxonomic s tatus of the fossil species R. tingianus Matthew and Granger, 1923, ar e unclear because the type specimen is a subadult.