Preliminary report on Sichuan golden snub-nosed monkeys (Rhinopithecus roxellana roxellana) at Laohegou Nature Reserve, Sichuan, China.

Comparative studies of subspecies under different ecological environments offer insights into intraspecies evolutionary adaptive mechanisms. Golden snub-nosed monkeys (Rhinopithecus roxellana) include three subspecies in China classified mainly by their morphological variations: R. r. roxellana (Sichuan and Gansu province), R. r. qinlingensis (Shaanxi province) and R. r. hubeiensis (Hubei province). These three subspecies live in three isolated area with different environments. Past works focused on the last two subspecies, but little information of habitat and behaviors of the nominated subspecies (R. r. roxellana) is available to date. We conducted a two-year study on the diet, activity budget, home range and social organization of 4 herds of R. r. roxellana, based on a total of 106 days' observation in Laohegou (LHG) Nature Reserve, Sichuan province. By using scan sampling method, our results suggest that the R. r roxellana feeds predominantly on leaves (77.5%), and spends more time feeding (40.0%) and resting (27.0%) while compared to the other two subspecies. Kernel Density Estimation Method based on GPS technology confirms that R. r roxellana has relatively larger home ranges (49.1 km2). The unit size (8.3 ± 3.5 individuals) of R. r roxellana is also smaller. Therefore, it is possible that differences in food availability in relation to habitats have important impacts on the feeding strategy and social system of the golden snub-nosed monkey. These results provide data to further explore intraspecific adaptations of living primates.

Brief communication: a cranial morphometric assessment of the taxonomic affinities of Trachypithecus auratus (E. Geoffroy, 1812 primates: Colobinae) with a reassessment of the T. auratus type specimen.

The debate over the taxonomic position and affinities of Trachypithecus auratus has been ongoing since its identification by E. Geoffroy Saint-Hilaire in 1812. The type specimen of this species is housed in Muséum national d'Histoire naturelle in Paris (MNHN-ZM 2005-912). This point is debated due to the complex and fluctuating taxonomy of Southeast Asian Colobinae (Brandon-Jones et al.: Int J Primatol 25 (2004) 97-164) and to the fact that this individual is represented by a mounted skeleton. By means of 3D medical imaging methodologies we describe for the first time the cranial anatomy of the specimen MNHN-ZM 2005-912 and compare it with other Trachypithecus species, in order to test the molecular systematic hypotheses for affinities among the T. auratus-T. cristatus group. We ascertain the taxonomic attribution of this individual to the species Trachypithecus auratus species. The most diagnostic characters shared by the type specimen and Trachypithecus auratus compared to other species of Trachypithecus are the rounded orbits and the straight facial profile. We then try to clarify the inconsistencies concerning the geographical provenance of the type. The island of Java appears to be the most probable locality from a cluster analysis based on linear morphometry. After this approach and a discriminant analysis, a northeastern Javanese provenance of this specimen, as proposed by Brandon-Jones et al. (Int J Primatol 25 (2004) 97-164) is dubious. Finally we provide 3D models of the skull and the endocast, and a list of cranial landmark coordinates of the holotype for future research.

Nuclear versus mitochondrial DNA: evidence for hybridization in colobine monkeys.

BACKGROUND: Colobine monkeys constitute a diverse group of primates with major radiations in Africa and Asia. However, phylogenetic relationships among genera are under debate, and recent molecular studies with incomplete taxon-sampling revealed discordant gene trees. To solve the evolutionary history of colobine genera and to determine causes for possible gene tree incongruences, we combined presence/absence analysis of mobile elements with autosomal, X chromosomal, Y chromosomal and mitochondrial sequence data from all recognized colobine genera. RESULTS: Gene tree topologies and divergence age estimates derived from different markers were similar, but differed in placing Piliocolobus/Procolobus and langur genera among colobines. Although insufficient data, homoplasy and incomplete lineage sorting might all have contributed to the discordance among gene trees, hybridization is favored as the main cause of the observed discordance. We propose that African colobines are paraphyletic, but might later have experienced female introgression from Piliocolobus/Procolobus into Colobus. In the late Miocene, colobines invaded Eurasia and diversified into several lineages. Among Asian colobines, Semnopithecus diverged first, indicating langur paraphyly. However, unidirectional gene flow from Semnopithecus into Trachypithecus via male introgression followed by nuclear swamping might have occurred until the earliest Pleistocene. CONCLUSIONS: Overall, our study provides the most comprehensive view on colobine evolution to date and emphasizes that analyses of various molecular markers, such as mobile elements and sequence data from multiple loci, are crucial to better understand evolutionary relationships and to trace hybridization events. Our results also suggest that sex-specific dispersal patterns, promoted by a respective social organization of the species involved, can result in different hybridization scenarios.