Molecular phylogeny of Mentawai macaques: taxonomic and biogeographic implications

In order to elucidate the evolutionary history and taxonomy of the Mentawai macaques, we sequenced a 567 base pairs (bp) long fragment of the mitochondrial cytochrome b gene from 39 individuals representing pigtailed macaque populations from Siberut, Sipora, South Pagai, and Sumatra. Pairwise difference analyses carried out within and among populations have shown, that: (1) variation within populations is relative low, (2) variation among populations is increased, and (3) pairwise differences within and among the populations from Sipora and South Pagai are in the same range. From phylogenetic tree reconstructions including further macaque species, we detected a paraphyletic origin of Mentawai macaques with the Siberut population more closely related to Macaca nemestrina from Sumatra, than it is to populations from the Southern islands. Based on these results, we favour a scenario in that macaques entered the Mentawai islands by two independent colonisation events. Taking together the paraphyletic origin of Mentawai macaques and the genetic differences detected among pigtailed macaque populations, which are comparable with those observed among the seven Sulawesi macaque species, we propose to separate macaques from Siberut and Sipora, North and South Pagai into two distinct species, Macaca siberu and Macaca pagensis, respectively.     

Island history affects faunal composition: the treeshrews (Mammalia: Scandentia: Tupaiidae) from the Mentawai and Batu Islands,Indonesia

The Mentawai and Batu Island groups off the west coast of Sumatra have a complicated geological and biogeographical history. The Batu Islands have shared a connection with the Sumatran ‘mainland’ during periods of lowered sea level, whereas the Mentawai Islands, despite being a similar distance from Sumatra, have remained isolated from Sumatra, and probably from the Batu Islands as well. These contrasting historical relationships to Sumatra have influenced the compositions of the respective mammalian faunas of these island groups. Treeshrews (Scandentia, Tupaiidae) from these islands have, at various times in their history, been recognized as geographically circumscribed populations of a broadly distributed Tupaia glis, subspecies, or distinct species. We used multivariate analyses of measurements from the skull and hands to compare the island populations from Siberut (Mentawai Islands) and Tanahbala (Batu Islands) with the geographically adjacent species from the southern Mentawai Islands (T. chrysogaster) and Sumatra (T. ferruginea). Results from both the skull and manus of the Siberut population show that it is most similar to T. chrysogaster, whereas the Tanahbala population is more similar to T. ferruginea, confirming predictions based on island history. These results are further corroborated by mammae counts. Based on these lines of evidence, we include the Siberut population in T. chrysogaster and the Tanahbala population in T. ferruginea. Our conclusions expand the known distributions of both the Mentawai and Sumatran species. The larger geographical range of the endangered T. chrysogaster has conservation implications for this Mentawai endemic, so populations and habitat should be re‐evaluated on each of the islands it inhabits. However, until such a re‐evaluation is conducted, we recommend that the IUCN Red List status of this species be changed from ‘Endangered’ to ‘Data Deficient’. Published 2013. This article is a U.S. Government work and is in the public domain in the USA, Biological Journal of the Linnean Society, 2014, 111 , 290–304.     

Variations in group composition and population density of the two sympatric Mentawaian leaf-monkeys

The Mentawai snub-nosed langur (Simias concolor) and the Mentawai langur (Presbytis potenziani) were observed on Siberut Island, off the west coast of Sumatra, for about 20 months during 1974–1978. The Mentawai snub-nosed langur was organized into monogamous groups in the major study area, but formed larger polygamous groups in some limited areas. Where larger polygamous groups were observed, the snub-nosed langur was found at an extremely high density. On the other hand, in the area where monogamous groups were observed, they occurred at a low density. Such differences in social organization are discussed in relation to excessive hunting by the natives. Mentawai langurs were found in small monogamous groups throughout the island, a condition never observed in any other known Old World monkeys.     

Phylogeographic analysis of pigtail macaque populations (Macaca nemestrina) inferred from mitochondrial DNA

Mitochondrial DNA variation was surveyed in nine populations of the pigtail macaque (Macaca nemestrina), covering all three recognized subspecies in Southeast Asia. To do this, a 2,300 base pair fragment spanning the mitochondrial NAD 3 and NAD 4 genes and flanking tRNA subunits leucine and glycine was targeted for amplification and digested with a battery of 16 restriction endonucleases. Out of a total of 107 individuals, 32 unique haplotypes could be distinguished. Parsimony and neighbor-joining analyses grouped the haplotypes into five strongly supported assemblages representing China/Thailand, Malaysia, Sumatra, Borneo, and Siberut. These results indicate that the mainland and island mtDNA haplotypes are strictly and uniquely limited to the geographic ranges of the recognized morphological subspecies. Cladistic and neighbor-joining analyses indicate that inferred phylogenies of mtDNA haplotypes are congruent with subspecies designations. Furthermore, in support of morphological studies, results indicate that the Mentawai macaque is most likely not a distinct species but a subspecies of M. nemestrina. Am J Phys Anthropol 104:35–45, 1997. © 1997 Wiley-Liss, Inc.     

Human predation and Kloss's gibbon (Hylobates klossii) sleeping trees in Siberut Island,Indonesia

Kloss's gibbons (Hylobates klossii) and Mentawai langurs (Presbytis potenziani) on Siberut Island, Indonesia, both sleep in emergent trees 34–55m tall, situated on crests and upper slopes of hills. They differ in that 91% of gibbon sleeping trees examined were free of lianas, whereas 89% of langur sleeping trees were draped with thick, woody lianas hanging from the branches to the ground. Because indigenous hunters climb lianas to shoot primates in treetops, gibbons are less susceptible than langurs to nocturnal human predation. Hence, the gibbons' preference for—and apparent control of—the limited supply of vineless trees gives them an advantage over langurs.     

History and ‘Mentawai’: Colonialism,Scholarship and Identity in the Rereiket,West Indonesia

This paper takes a critical look at the discursive construction of the identity of ‘the Mentaiwaians’ who are purported to inhabit the Mentawai islands in Western Indonesia. Out of a range of possible indigenous representations of identity ‘Mentawaian’ is the one that travellers and scholars universally use. I trace the formation of this representation in the very early literature on the islands authored by traders, travellers, scholars and missionaries. I then go on to examine the (hegemonic) effects of this on the way in which anthropologists have subsequently come to construct discursively the ‘culture’ of the ‘Mentawaians’. As an alternative, I propose that anthropological scholarship needs to take greater heed of the ways in which the local inhabitants construct their own identities. I briefly illustrate this through the example of my own work which describes a shifting and contextual construction of local identity in a particular locale on Siberut, the largest of the Mentawai islands.     

Acoustic Niches of Siberut Primates

The loud calls nonhuman primates use in long-distance communication have supposedly been selected for efficient information transfer in the habitat. The differential effects of scattering and reverberation and the masking effects of background noise predict that loud calls produced in rain forest habitats should be low-pitched and whistle-like with low-frequency modulation. Callers may also use particular calling posts or times of day with reduced background noise to increase the efficacy of sound transmission. We studied the loud calls of the 4 sympatric primate species on Siberut Island. Only Kloss gibbons (Hylobates klossii) fulfilled the predictions regarding both the structure and use of calls. Though the other 3 species —Mentawai macaques (Macaca siberu), pig-tailed langurs (Simias concolor), and Mentawai leaf monkeys (Presbytis potenziani)— also concentrated their main energies in the spectral window with the lowest background noise, their calls were not adapted to long-range transmission. All 4 species produced loud calls exclusively no lower than 18 m above ground, but food abundance and shelter in the canopy may also be factors. Though all 4 species produced the majority of loud calls in the morning, it was not the only time of day with reduced background noise. We suggest that phylogenetic inheritance may better explain the structure of calls than adaptation to the habitat. In sum, the observed usage of spectral and temporal niches is not solely an adaptation to the sound profile of the habitat, though it clearly improves their transmission.     

Singing by male and female Kloss gibbons (Hylobates klossii) in the Peleonan Forest, Siberut Island, Indonesia

Kloss gibbons (Hylobates klossii) are endemic to the Mentawai Islands in Indonesia and are one of only two gibbon species in which mated pairs do not sing duets. This is the first long-term study of the factors influencing the singing activity of Kloss gibbons within a northern Siberut Island population and follows two previous studies in central Siberut nearly 30 years ago. We collected data on the presence/absence of male and female singing within the study area on 198 days and within a focal group on 47 days. Rainfall during the time period in which they normally sing inhibits singing in both males and females. Our study supports the hypothesis that male and female songs function in intrasexual resource defence, as singing is associated with singing by same-sex neighbours, and same-sex choruses are more likely to occur after one or more days of silence (from that sex), suggesting there is pressure for individuals to communicate with same-sex neighbours regularly. Singing was not coordinated within a mated pair, suggesting that vocal coordination of the pair has been lost with the loss of the duet and that Kloss gibbon songs do not convey information to neighbours about the strength of the pair bond. On days when males sang predawn, females were more likely to sing after dawn and earlier in the morning. Additionally, the number of groups singing in female choruses was positively associated with the number of males that had sung in the predawn male chorus. We suggest that female songs have an intersexual territory defence as well as an intrasexual function.     

Molecular phylogeny and evolutionary history of Southeast Asian macaques forming the M. silenus group

The 12 presently recognized taxa forming the Macaca silenus group represent the most diverse lineage within the genus Macaca. The present study was set up to clarify the phylogenetic relationships of the extant members of the M. silenus group and to explain their geographical distribution patterns seen today. A combined approach involving the analysis of one paternal (TSPY) and two maternal (cyt b and 12S-16S rRNA) molecular markers enabled us to resolve the phylogenetic relationships within this lineage. Our Y chromosomal marker is not informative enough to allow detailed conclusion. Based on our mitochondrial data, however, M. pagensis, endemic to the three southern Mentawai islands (Sipora, North- and South Pagai), split off early (2.4-2.6 mya) and represents a sister clade to the macaques from the northern Mentawai island of Siberut and from those of the Southeast Asian mainland, which diverged in a radiation-like splitting event about 1.5-1.7 mya. By combining our new results with available data on behavioural as well as climate and sea level changes in Southeast Asia during the Plio- and Pleistocene, we have developed two scenarios for the evolutionary history of this primate group, which may help explain the current geographical distribution of its members.     

Shamanism,Tourism, and Secrecy: Revelation and Concealment in Siberut,Western Indonesia

ABSTRACT

This essay attempts to explain why international backpacker tourists in Indonesia are so interested in indigenous religion and especially in shamanism. It articulates the indigenous mode of analysis or reverse anthropology of the people whom the tourists visit: in this case, the Sakaliou clan on the island of Siberut, the largest of the Mentawai Islands off the west coast of Sumatra. According to Sakaliou, tourists seem to be looking for something they have lost, a kind of secret knowledge that is possessed by the shaman. Unlike other people, who keep their secrets in isolation, the shaman must skilfully reveal some of his secret knowledge as part of a public performance. It is this secret knowledge, indicated by the skilled revelation of skilled concealment, for which tourists seem to be searching among the members of the Sakaliou clan and their shamans.     

Phylogenetics and Biogeography of the <Emphasis Type="Italic">Phalaenopsis violacea</Emphasis> (Orchidaceae) Species Complex Based on Nuclear and Plastid DNA

The Phalaenopsis violacea complex includes two species: P. violacea Witte and Phalaenopsis bellina (Rchb.f.) E. A. Christ. However, three forms of P. violacea have been found in different areas, including Sumatra, the Malay Peninsula, and Mentawai Island. The phylogenetic tree inferred from the internal transcribed spacer (ITS) region of nuclear ribosomal DNA (nrDNA), the trnL intron, and the atpB-rbcL spacer of plastid DNA were used to clarify the phylogenetics and biogeography of the P. violacea complex. Analyses of the trnL intron sequences and of the atpB-rbcL spacer did not allow for apparent discrimination among these three species of the P. violacea complex. Based on the phylogenetic tree inferred from the ITS sequence, P. bellina cannot be separated from populations of P. violacea, with the exception of the population distributed on Mentawai Is., Indonesia. Based on morphological characteristics, P. violacea distributed on Mentawai Is. has a long and roundish rachis and is separate from the other groups of the P. violacea complex described by Christenson (Timber, Portland, OR, 2001). Therefore, the results of this study show a trend that supports the conclusion that the population of the P. violacea complex on Mentawai Is. is a separate species from P. violacea. Based on the biogeography of the P. violacea complex, Mentawai plants of this complex might be descended from those on the Sumatra/Malay Peninsula.     

Habitat Use and Trophic Niche Overlap of Two Sympatric Colobines, Presbytis potenziani and Simias concolor, on Siberut Island, Indonesia

According to ecological theory, the concept of niche differentiation is essential to our understanding of how sympatric species can limit competition over resources. We here examine ecological niche differentiation in 2 sympatric Asian langurs, Presbytis potenziani and Simias concolor, both endemic to the Mentawai Islands off the west coast of Sumatra. We collected data (home range size, canopy use, activity budgets, diet, and niche breadth and overlap) using GPS and scan/focal animal sampling methods on 2 groups of Presbytis potenziani and 3 groups of Simias concolor living in a mixed primary rain forest in northern Siberut. Results show that home ranges of the 2 species overlapped completely and that the home range size of Presbytis potenziani was ca. 4 times larger than that of Simias concolor. Lower canopy levels (<20 m) were used more often by Simias concolor, whereas Presbytis potenziani preferred the canopy >20 m. Apart from foraging and other activities, there was little difference in overall activity budgets of the 2 species. Regarding diet, although 60% of all food species examined were used by both langur species, they shared only 3 of the 10 most commonly eaten species. Presbytis potenziani fed more selectively on fruits, whereas Simias concolor fed predominantly on leaves. Levin’s niche breadth indices revealed that the diet of Simias concolor is more general (0.34) than that of Presbytis potenziani (0.22). Based on a Pianka index of 0.32, we conclude that there is a relatively small food niche overlap between the 2 colobine species and that diet represents an important mechanism enabling their coexistence.     

Small gods,rituals, and cooperation: The Mentawai water spirit Sikameinan

Cognitive and evolutionary research has focused on the powerful deities of large-scale societies, yet little work has examined the smaller gods of animist traditions. In a study of the water spirit Sikameinan of the Mentawai people (Siberut Island, Indonesia), we address three questions: (1) Are smaller gods believed to enforce cooperation, especially compared to bigger gods in larger-scale societies? (2) Do beliefs in these deities encourage people to engage in behavior otherwise perceived as costly? and (3) Does ritual reinforce beliefs in these deities? Drawing on interview responses, data from healing ceremonies, and ethnographic observation, we show that Sikameinan is believed to punish people who violate meat-sharing norms and that people ‘attacked’ by Sikameinan pay shamans to conduct healing rituals. The public nature of rituals, involving prestigious individuals apologizing to Sikameinan for the patient's stinginess, reinforce onlookers' beliefs about Sikameinan. The most widely shared beliefs about Sikameinan are represented in rituals while beliefs not represented vary considerably, indicating that ritual may be potent for cultural transmission. These results suggest that moralizing supernatural punishers may be more common than suspected and that the trend in the cultural evolution of religion has been an expansion of deities' scope, powers, and monitoring abilities.     

Feeding and ranging in the Mentawai Island langur (Presbytis potenziani)

Presbytis potenziani is found only on the Mentawai Islands, Indonesia, and its ecology and feeding and ranging behavior have been little studied. I studied 10 groups ofPresbytis potenziani in the primary forests of North Pagai Island, Mentawai, Indonesia.P. potenziani used primarily the upper strata of the forests for feeding, movement, and resting. Groups remained cohesive during their daily activities, ranged between 100 to > 1000 m daily, and occupied home ranges of ≤ 40 ha. Neither sex predominantly initiated group movement. Locomotion was primarily quadrupedal, with frequent leaping. P. potenziani showed two feeding peaks, one in early morning and one during midafternoon. P. potenziani fed mainly on climbers and trees of the Dipterocarpaceae. They ate primarily leaves, but also fed on fruits and other plant parts.     

Macaque evolution and dispersal in insular south-east Asia

The evolution of primates is usually approached from the standpoint of adaptation and interspecific competition. However, climatic and eustatic changes associated with periodic glaciations have had a profound influence on their geographical distribution, favouring the intervention of contingency in evolution. This paper deals with the role of chance and competition in the dispersal and stocking of macaques in the islands of south-east Asia. The genus Macaca is unique among non-human primates for the range of habitats colonized, from continents to islands. We first review current knowledge about the zoogeography of macaques in Sundaland. We point out the inconsistencies present in the hypotheses thus far proposed to account for the colonization of shallow- and deep-water islands. We then propose a new perspective of macaque dispersal through the Indonesian archipelago, which takes into account sea-level changes, as well as latitudinal and altitudinal rainforest shifts following climatic cycles during the Quaternary. We envision three steps: (i) dispersal and partial disappearance of the first radiation of macaques; (ii) primary mainland recolonization by pigtailed and longtailed macaques; and (iii) secondary sea-rafting colonization by longtailed macaques. This model implies that liontailed, Sulawesi and Mentawai macaques stemmed from pre-glacial remnant populations, whereas pigtailed macaques originated in post-glacial populations that diverged later on. The model accounts for the distribution of longtailed macaques throughout the Indonesian archipelago. The riverine habits of this species would have favoured its dispersal by sea rafting, which was otherwise extremely rare for other primate species. Stocking would have been successful for longtailed macaques only in islands where no other macaque competitors were already present. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 555–576.     

Demography of Simakobu (Simias concolor) and the impact of human disturbance

Asian colobines typically live in small one-male groups (OMGs) averaging five adult females, but Simias concolor (simakobu or pig-tailed langur) is considered an exception because mostly adult male-female pairs have been reported. However, based on their phylogenetic position and marked sexual dimorphism, simakobu are also expected to form OMGs with multiple females. The preponderance of small groups could be the result of human disturbance (hunting or habitat disturbance) reducing group size in the recent past. To investigate this possibility, we documented the demography of ten wild simakobu groups from January 2007 until December 2008 at an undisturbed site, the Peleonan Forest, Siberut Island, Indonesia. We assessed the population-specific size and composition of groups and documented demographic changes due to births, disappearances, and dispersals throughout our 2-year study. We found OMGs with 3.0 adult females on average in addition to all-male groups, but no adult male-female pairs. The ratio of 0.5 infants per adult female (and 0.64 births per female-year in focal groups) suggested that birth rates were similar to those of other Asian colobines. In 5.1 group-years, we observed six dispersal events and six temporary presences (i.e., less than 3 months' residency). Both males and females dispersed, and juveniles seemed to disperse more frequently than adults. To assess the impact of human disturbance on simakobu demography, we compiled data for seven additional populations from the literature and compared them using multiple regressions. Adult sex ratio and the number of immatures per group were influenced negatively by hunting and positively by habitat disturbance while reproductive rates were not significantly affected by either variable. These findings suggest that adult male-female pairs may result from hunting pressure reducing group size, and that conservation action to reduce hunting in the Mentawai Islands is needed to ensure the survival of this critically endangered species.     

Interspecific spacing between gibbons (Hylobates klossii) and langurs (Presbytis potenziani) on Siberut Island,Indonesia

Spatial arrangement and social interactions of two sympatric and ecologically similar primate species, Hylobates klossii and Presbytis potenzianai, are described from field observations made between July 1972 and October 1974 on Siberut Island, Indonesia. Gibbon territories and langur home ranges overlap extensively. Because gibbons have the ability to supplant langurs at shared food sources, langurs are at a competitive disadvantage. To avoid or decrease the frequency of hostile interactions with gibbons, langurs locate their core areas on boundaries between adjacent gibbon territories, which permits langurs to retreat across these barriers in response to gibbon movements. Langurs further enhance segregration by leaving their sleeping trees earlier than gibbons, gaining additional feeding time on contested food sources. This form of interspecific spatial organization between gibbons and langurs resembles certain predator-prey spacing systems, where territorial boundaries between adjacent predators serve as sanctuaries for prey populations.     

Morphometric analysis ofMacaca arctoides andM. thibetana in relation to other macaque species

As a first step in reviewing the classification of the two stump-tailed macaque species,Macaca arctoides andM. thibetana, as compared with other species of the genusMacaca, 72 linear dental and cranial variables of 11 macaque species were examined by morphometric analyses. The results indicate that the two stump-tailed species are the largest of the macaques and although rather similar overall, they exhibit significant differences in the pattern of variation in most of the five skull regions as shown by Principal Components and Canonical Variate Analyses. Euclidean Distances based on Canonical Variate scores indicate that the females ofM. arctoides andM. thibetana are more widely separated than eight other pairs of macaque species, and that the separations of the respective males are greater than those of three other pairs of species. These findings are consistent withFooden's classification of the stump-tailed macaques as two separate species (Fooden, 1976;Fooden et al., 1985). The present results suggest, as other researchers have proposed on the basis of external features, biochemistry and genetics, that the two stump-tailed macaque species andM. assamensis are closely related. The results also tentatively imply associations withM. fuscata andM. sylvanus but these require further study. The findings have implications for the assessment of the various Chinese Pleistocene macaque fossils.     

Reduced TCOF1 mRNA level in a rhesus macaque with Treacher Collins-like syndrome: further evidence for haploinsufficiency of treacle as the cause of disease

Mutations in the human gene TCOF1 cause a mandibulofacial dysostosis known as Treacher Collins syndrome (TCS). An infant rhesus macaque (Macaca mulatta) that displayed the TCS phenotype was identified at the California National Primate Research Center. The TCOF1 coding region was cloned from a normal rhesus macaque and sequenced. The rhesus macaque homolog of TCOF1 is 91.6% identical in cDNA sequence and 93.8% identical in translated protein sequence compared to human TCOF1. Sequencing of TCOF1 in the TCS-affected rhesus macaque showed no mutations within the coding region or splice sites; however, real-time quantitative PCR showed an 87% reduction of spleen TCOF1 mRNA level in the TCS affected macaque when compared with normal macaque spleen. Nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession numbers DQ085095 and DQ085096.     

Mentawai’s endemic,relictual fauna: is it evidence for Pleistocene extinctions on Sumatra?

Aim The four Mentawai islands, south‐west of Sumatra, have long been isolated from the remainder of Sundaland, resulting in a high level of endemism. We examined the distribution of 151 species of the Mentawai Islands in Sundaland and assessed various processes that may have resulted in the various biogeographical patterns. Location Southeast Asia, particularly the Mentawai Islands and nearby large landmasses (Sumatra, Java, Borneo and Peninsular Malaysia). Methods We compared the faunal composition of the Mentawai Islands for selected taxa (43 mammals, 92 reptiles and 16 amphibians) with that of the four nearby large landmasses of Sundaland using morphological comparisons and the most recent molecular phylogenetic analyses available in the literature. These comparisons yielded sister taxa, which were used to simulate species absence data for the four Sundaland landmasses under several scenarios to investigate how patterns of species absence could have arisen. Results In contrast to our expectations, several Mentawai species did not have their closest relatives on neighbouring Sumatra, but rather on the more distant Borneo, Java or Peninsular Malaysia. For mammals, the similarity between species from Mentawai and Borneo was greater than that observed between species from Mentawai and Sumatra. We conclude that the relationships represent traces of species historically distributed throughout Sundaland that became extinct in Sumatra during the Pleistocene. For reptiles and amphibians the observed pattern of species absences generally resembled the simulated pattern expected under the scenario of absence rates increasing with landmass isolation, whereas for mammals we observed more species than expected missing from Java and Sumatra, and fewer than expected from Borneo. Main conclusions The potential extinctions on Sumatra probably had two causes: changes of climate and vegetation during the Pleistocene and environmental impacts from the Toba supervolcanic eruption.