More species of nocturnal primates are now recognized than in the past, because many are cryptic species. Subtle morphological disparities, such as pelage pattern and color variation, vocal cues, and genetics have aided in elucidating the number of diagnosable species in a genus. The slow lorises (genus Nycticebus) once included only two species, but recent taxonomic studies resulted in the description of three additional species; further incompletely explored variability characterizes each of the currently described species. The Bornean loris in particular is characterized by pelage and body size variation. In this study, we explored facemask variation in the Bornean loris (N. menagensis). Differing facemask patterns, particularly influenced by the amount of white on the face, significantly clustered together by geographic regions, separated by notable geographic boundaries. Our results support the recognition of four species of Bornean lorises: N. menagensis, N. bancanus, N. borneanus, and N. kayan. Genetic studies are required to support these findings and to refine further our understanding of the marked variability within the Bornean loris populations.
This discovery points to the importance of Angolan forests as refuges for endemic biodiversity. These forests are under severe threat from overexploitation, and there is an urgent need to establish conservation measures and designate protected areas.
The evolution of color variation in organisms highlights the selective pressures that impact survivability. Research on color variation has demonstrated coloration contributes to the ability of animals to conceal themselves from predators, to regulate body temperatures, to advertise their toxicity, or to attract mates (c.f. Caro, 2005). For taxonomists, striking color differences and patterns have been used
We can gain a better understanding of elusive nocturnal mammals through live trapping them to gain vital samples and measurements and through following them in the night with radio or GPS collars. Studies that involve humane live-trapping of a species open the doors into better understanding a species' evolution, diversity, adaptations, and behaviour. We review 11 studies that have attempted to trap lorises and pottos with physical traps, and show that this method yields very low success, and is achievable largely with traps specifically built and designed for the species. Hand trapping, however, was successful in 7 studies, and we make recommendations for this procedure. Once caught, we provide a detailed list of measurements and samples that can be taken, and review 14 studies (both reintroduction and wild) that have used various radio collars to track lorises and pottos. We intend that these recommendations will provide a standard by which lorises and pottos can be compared throughout their range.
Genetic analysis of historical museum collections presents an opportunity to clarify the evolutionary history of understudied primate groups, improve taxonomic inferences, and inform conservation efforts. Among the most understudied primate groups, slow and pygmy lorises (genera Nycticebus and Xanthonycticebus) are nocturnal strepsirrhines found in South and Southeast Asia. Previous molecular studies have supported five species, but studies using morphological data suggest the existence of at least nine species. We sequenced four mitochondrial loci, CO1, cytb, d-loop, and ND4, for a total of 3324 aligned characters per sample from 41 historical museum specimens for the most comprehensive geographic coverage to date for these genera. We then combined these sequences with a larger dataset composed of samples collected in Vietnam as well as previously published sequences (total sample size N = 62). We inferred phylogenetic relationships using Bayesian inference and maximum likelihood methods based on data from each locus and on concatenated sequences. We also inferred divergence dates for the most recent common ancestors of major lineages using a BEAST analysis. Consistent with previous studies, we found support for Xanthonycticebus pygmaeus as a basal taxon to the others in the group. We also confirmed the separation between lineages of X. pygmaeus from northern Vietnam/Laos/China and southern Vietnam/Cambodia and included a taxonomic revision recognizing a second taxon of pygmy loris, X. intermedius. Our results found support for multiple reciprocally monophyletic taxa within Borneo and possibly Java. The study will help inform conservation management of these trade-targeted animals as part of a genetic reference database for determining the taxonomic unit and provenance of slow and pygmy lorises confiscated from illegal wildlife trade activities.
Throughout much of Asia, slow lorises (Nycticebus) and tarsiers (Tarsius) live allopatrically, but on several islands, including Sumatra and Borneo, they occur in sympatry. Dwindling habitats could result in resource competition within these sympatric populations, as the diets of these species overlap. To assess the possibility of resource competition, we gathered data from the literature on the abundance and microhabitat structure of slow loris and tarsier species throughout their ranges. We also estimated abundances of Bornean lorises Nycticebus menagensis and western tarsiers Tarsius bancanus borneanus and investigated their habitat use in Sabah, Malaysian Borneo. We predicted that species living sympatrically would favor different heights, and thus different microhabitat structures from congeners, and have lower abundances compared with allopatric species because of limiting factors. Across their ranges, loris density did not vary regardless of whether they were allopatric or sympatric. However, across sympatric and allopatric tarsier ranges, there were significant differences in densities (sympatric: 3−27 ind. km ). Microhabitat use varied significantly between sympatric and allopatric loris populations (p = 0.036) but not between sympatric and allopatric tarsier populations. Our results, although based on a limited amount of data, suggest that tarsiers are impacted by the presence of slow lorises in their habits, and these populations should be monitored, especially as habitat sizes dwindle and resources continue to become scarce.
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