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Small monkeys...
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Images of (most) extant Macaque (Genus: Macaca) species of the world. Northern Pig-tailed Macaque (Macaca leonina), Southern Pig-tailed Macaque (Macaca nemestrina) Japanese macaque (Macaca fuscata), Barbary Macaque (Macaca sylvanus), Rhesus macaque (Macaca mulatta), Long-tailed macaque (Macaca fascicularis), Stump-tailed macaque (Macaca arctoides), Lion-tailed macaque (Macaca silenus), Sulawesi Macaque (Macaca nigra), Moor macaque (Macaca maura) & Formosan rock macaque (Macaca cyclopis).
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(08-12-2024, 05:06 PM)TheHyenid76 Wrote: A strange image! A young hybrid between a Phayre's langur and a Capped langur. They're both of the genus Trachypithecus. The second pic shows the young primate with its mother a Capped langur and its father is a Phayre's langur. Credits to Dr Monirul H. Khan. Source. (08-13-2024, 11:23 PM)TheHyenid76 Wrote: It seems there are more than one hybrid young langurs. Dr Monirul Khan writes: "Hybrid (no. 3) langur baby playing with a leaf while its mother was roosting on a nearby branch at Satchari National Park, Bangladesh; Jul 2024. This is the third and the youngest of the three hybrid langurs having Phayre's Langur father and Capped Langur mother." Satchari National Park and Northeast Bangladesh in general are very important places for the primates of Bangladesh however their habitats are being destroyed rapidly. Information aside, he/she is just soo cute! Hybridization between Capped Langurs and Phayre's Langur The northeast of Bangladesh (Sylhet division) is an important region for the biodiversity of the country. The forests in this region are host to many globally threatened primates e.g Hoolock Gibbon, Northern Pig-Tailed Macaque & Phayre's langur. Also these forests contain bears, small wild cats and other mammalian fauna. Despite this, the forests are deteriorating due to severe anthropogenic threats like deforestation, hunting, development and much more. Due to this, a rare but not unknown problem is occurring. The reduction in forest area is forcing capped langurs and Phayre's langurs (both Colobines) to breed and produce hybrids (some of whom are fertile). If such hybridization continues it can lead to the extinction of both species. Forest loss forces langur species to interbreed New danger for endangered primates Research of the German Primate Center-Leibniz Institute for Primate Research - shows a threatening development for two endangered primate species in Bangladesh: Phayre's langurs (Trachypithecus phayrei) and capped langurs (Trachypithecus pileatus). In mixed groups of these two species, hybrids have been found and genetically confirmed. If hybridization continues, it could mean the extinction of one or both species (International Journal of Primatology). Over five years (2018-2023), an international team of researchers led by Tanvir Ahmed, a PhD student at the German Primate Center, studied the langur populations in north-eastern Bangladesh. They found that 8 of the 98 langur studied groups consisted of Phayre's and capped langurs, and in three groups, some individuals appeared as a mixture of the two species. Later, researchers analyzed genetic samples of the species in the lab of the German Primate Center, and confirmed one case of hybridization. This langur had a capped langur mother and a Phayre's langur father. Another female with a hybrid appearance showed signs of motherhood, indicating that at least female hybrids are fertile and give birth to young. Hybridization: A still rare but growing problem worldwide Hybridization is generally rare among primates but occurs in areas where the distribution ranges of related species overlap. Human activities such as deforestation, habitat fragmentation, hunting and trapping of primates, leading to a thinning of populations and restricting the movements of individuals between local populations, can increase the risk of such hybridization. Tanvir Ahmed, lead author of the study, says: ‘The existence of fertile hybrids is particularly alarming because it suggests that gene flow between these two endangered species could irreversibly affect their future genetic composition.’ Christian Roos, lead scientist of the study, emphasizes the global relevance of the research results: ‘This is not just a local problem. When habitats are destroyed, animals mix unnaturally and form mixed groups and hybridization might occur. This can even mean the extinction of one or both species.’ Urgent need for action: Forest protection and research as the key to conservation strategies The study also showed that well-protected forests have a higher population density of langurs compared to less protected ones. However, these forests are often too small, too isolated and fragmented to ensure the long-term survival of the species. ‘Forest conservation must become a national priority. If we don't act now, we risk losing not only two monkey species but also an important part of Bangladesh's biodiversity,’ says Tanvir Ahmed. In addition to forest protection, ongoing research is needed to better understand the effects of hybridization and to develop suitable conservation strategies. Dietmar Zinner, co-author of the study, summarizes: ‘This study is a wake-up call. We need more data to develop effective long-term conservation strategies. Further research will help us understand the extent of hybridization, the impact of human activities and how to prevent its worst effects.’ With less than 500 Phayre's langurs and 600 capped langurs in north-east Bangladesh, time is running out for these species. Their survival depends on immediate action, including both forest conservation and creating dispersal corridors for the species between the forests. The next steps As part of his doctoral project, which is supported by the German Primate Center and the German Academic Exchange Service (DAAD), researcher Tanvir Ahmed is now focusing on a large-scale genetic study of langur populations and their vulnerability to climate change. The findings should contribute to an adapted action plan for the protection of langurs in Bangladesh. Scientific Literature Mixed-species association and a record of a hybrid offspring between Trachypithecus pileatus and Trachypithecus phayrei in Bangladesh Abstract The term mixed-species association has a broad range of definitions, from temporary foraging association to permanent group living. A mixed-species association mostly involves species from closely related taxa and is found in birds, mammals and fish. It ranges from passive association with little interaction to coordinated behavioural interactions between the group members of a mixed-species group. Mixed-species association can result in the production of hybrid offspring in the wild. In this study, we present, to the best of our knowledge, the first observational evidence of mixed-species association between the two threatened primate species Phayre's langur (Trachypithecus pileatus) and capped langur (Trachypithecus phayrei), in fragmented forest patches of northeast Bangladesh. We also report a presumed hybrid offspring between these species. We conducted a short-term study from December 2021 to April 2022 in three forest patches based on information from eco-tourism guides. We confirmed the presence of three mixed-species troops; in two of the groups an adult male T. phayrei had permanently immigrated into a group of T. pileatus, and in the other one an adult male T. pileatus had permanently immigrated into a group of T. phayrei. A long-term detailed study is needed to elucidate the reasons for these mixed-species associations, their behavioural patterns, the fate of the presumed hybrid offspring, and to understand the genetic relatedness between the individuals. Mixed-Species Groups and Genetically Confirmed Hybridization Between Sympatric Phayre’s Langur (Trachypithecus phayrei) and Capped Langur (T. pileatus) in Northeast Bangladesh Abstract Interspecific hybridization occurs almost in all major primate radiations. Intermediate phenotypes, sometimes seen in mixed-species groups, are often the first indications of hybridization. Beyond natural hybridization, human activities, such as habitat fragmentation or population depletion, can be important drivers for initiating or intensifying the formation of mixed-species groups and hybridization. As hybridization can lead to the cyto-nuclear extinction of species, it may pose additional threats to threatened primates. To assess the frequency of mixed-species groups and intermediate phenotypes between threatened Phayre’s (Trachypithecus phayrei) and capped langurs (T. pileatus), we conducted population surveys in six forests of northeast Bangladesh between 2018 and 2023. We also tested the hybrid status of one individual with intermediate phenotype genetically, by sequencing the maternally-inherited mitochondrial cytochrome b gene and fragments of two biparentally-inherited loci. During our surveys, we encountered 98 groups of langurs of which 41 were Phayre’s langur groups, 49 capped langur groups, and eight mixed-species groups (8%). In three mixed-species groups, we detected three individuals of intermediate phenotype, among them one adult female whose nipples were elongated indicating that she had an infant, and thus was likely to be fertile. Genetic analyses confirmed the hybrid status (most likely F1) of one individual with intermediate phenotype. To our knowledge, there are no reports of mixed-species groups and hybridization from other parts of the range where the species occur sympatrically. Hence, it seems likely that such groups occur mainly in the northern part of their common range where natural habitats are deteriorating fast. Therefore, we suggest monitoring of the populations, to find out whether the frequency of mixed-species groups increases, and a large-scale population genetic study to investigate whether hybridization is a recent phenomenon or occurred historically in the zone of range overlap in Bangladesh. Images of one hybrid individual and its parents. Photos from the article by German Primate Center. [A juvenile hybrid langur in Rema-Kalenga Wildlife Sanctuary, Bangladesh. One can easily recognized the mixture of morphological characters. For examplethe white eye rings of the Phayre's langurs and the golden-brown breast hair of the capped langurs.]  *This image is copyright of its original author [An adult female capped langur, the mother of the hybrid with another newborn baby.]  *This image is copyright of its original author [An adult male Phayre's langur, the father of the hybrid.]  *This image is copyright of its original author
Gibbon Taxonomy and Scientific Literature on Every Species
Gibbons are a group of small ape species that form the taxonomic family, Hylobatidae. They are apes meaning they are in the same Superfamily as Chimpanzees and Gorillas. Gibbons are only found in the forests of South and Southeast Asia and Southern China. Indonesia has the highest number of endemic Hylobatid (gibbon) species. The Hylobatidae family consists of 20 species which are split into four genera (plural of genus). In this post, I will be covering only the genus Hoolock. The other genera will be covered in following posts. The genus Hoolock is split to three species. All four species are found in the following countries: Bangladesh, India, China & Myanmar. Western Hoolock Gibbon (Hoolock hoolock)
Eastern Hoolock Gibbon (Hoolock leuconedys)
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