20 research outputs found

    Notes on large mammals of Bario, Sarawak

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    New species of Luperosaurus (Squamata: Gekkonidae) from the Crocker Range Park, Sabah, Malaysia (Borneo)

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    A new species of Luperosaurus is described from the Crocker Range Park, Sabah, northern Borneo (East Malaysia). The new species is known only from the holotype (SVL 34.7 mm), and is diagnosable from congeneric species by possession of the following combination of characters: body robust; head narrower than body; auricular opening oval-squarish; subrictal tubercles present; two intersupranasals contacting rostral; rostral in contact with nares; nine supralabials at midorbital position; 14/15 (R/L) supralabials to posterior edge of orbit of eye; 11 infralabials to posterior edge of orbit; dorsal body scales rounded, convex and granular; ca. 104 dorsal scale rows; 45 ventral scale rows; ca. 149 midbody scale rows; 1–3 anteriormost chin scales subequal, larger than those to their posterior; ventrolateral body tubercles spinose; three distal scansors deeply notched; tail fringe with distinct serrations; and pale rounded spots on middorsum

    Phylogenetic relationships of Malaysian monkeys, Cercopithecidae, based on mitochondrial cytochrome c sequences

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    Mitochondrial DNA cytochrome c oxidase II (COII) gene sequences of Malaysian Cercopithecidae were examined to ascertain their phylogenetic relationships. Colobinae were represented by the genera Presbytis, Trachypithecus and Nasalis, while the genus Macaca represented Cercopithecinae. DNA amplification and sequencing of the COII gene was performed on 16 samples. Symphalangus syndactylus (Hylobatidae) was used as the outgroup. Data were analyzed using both character (maximum parsimony) and distance (neighbor-joining) methods. Tree topologies indicated that Colobinae and Cercopithecinae have their own distinct monophyletic clade. This result was well supported by bootstrap values and genetic distances derived from the Kimura-2-parameter algorithm. Separation of Macaca nemestrina from M. fascicularis was also well supported by bootstrap values. In addition, tree topologies indicate a good resolution of the Colobinae phylogenetic relationships at the intergeneric level, but with low bootstrap support. The position of Nasalis remained problematic in both trees. Overall, COII is a good gene candidate for portraying the phylogenetic relationships of Malaysian primates at the inter- and intra-subfamily levels

    Euarchontan opsin variation brings new focus to primate origins

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    Debate on the adaptive origins of primates has long focused on the functional ecology of the primate visual system. For example, it is hypothesized that variable expression of short- (SWS1) and middle-to-long-wavelength sensitive (M/LWS) opsins, which confer color vision, can be used to infer ancestral activity patterns and therefore selective ecological pressures. A problem with this approach is that opsin gene variation is incompletely known in the grandorder Euarchonta, i.e., the orders Scandentia (treeshrews), Dermoptera (colugos), and Primates. The ancestral state of primate color vision is therefore uncertain. Here we report on the genes (OPN1SW and OPN1LW) that encode SWS1 and M/LWS opsins in seven species of treeshrew, including the sole nocturnal scandentian Ptilocercus lowii. In addition, we examined the opsin genes of the Central American woolly opossum (Caluromys derbianus), an enduring ecological analogue in the debate on primate origins. Our results indicate: 1) retention of ultraviolet (UV) sensitivity in C. derbianus and a shift from UV to blue spectral sensitivities at the base of Euarchonta; 2) ancient pseudogenization of OPN1SW in the ancestors of P. lowii, but a signature of purifying selection in those of C. derbianus; and, 3) the absence of OPN1LW polymorphism among diurnal treeshrews. These findings suggest functional variation in color vision of nocturnal mammals and a distinctive visual ecology of early primates, perhaps one that demanded greater spatial resolution under light levels that could support cone-mediated color discrimination

    Evolutionary and ecological forces influencing population diversification in Bornean montane passerines

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    The mountains of Borneo are well known for their high endemicity and historical role in preserving Southeast Asian rainforest biodiversity, but the diversification of populations inhabiting these mountains is poorly studied. Here we examine the genetic structure of 12 Bornean montane passerines by comparing complete mtDNA ND2 gene sequences of populations spanning the island. Maximum likelihood and Bayesian phylogenetic trees and haplotype networks are examined for common patterns that might signal important historical events or boundaries to dispersal. Morphological and ecological characteristics of each species are also examined using phylogenetic generalized least-squares (PGLS) for correlation with population structure. Populations in only four of the 12 species are subdivided into distinct clades or haplotype groups. Although this subdivision occurred at about the same time in each species (ca. 0.6– 0.7 Ma), the spatial positioning of the genetic break differs among the species. In two species, northeastern populations are genetically divergent from populations elsewhere on the island. In the other two species, populations in the main Bornean mountain chain, including the northeast, are distinct from those on two isolated peaks in northwestern Borneo. We suggest different historical forces played a role in shaping these two distributions, despite commonality in timing. PGLS analysis showed that only a single characteristic—hand-wing index—is correlated with population structure. Birds with longer wings, and hence potentially more dispersal power, have less population structure. To understand historical forces influencing montane population structure on Borneo, future studies must compare populations across the entirety of Sundaland

    Female call preferences in tree-hole frogs: why are there so many unattractive males?

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    In tree-hole frogs, Metaphrynella sundana, the fundamental call frequency varies widely between males. In field playback experiments, females strongly preferred calls from the lower range of frequencies found in the population. There was no correlation, however, between male size and call frequency, as is normally the case for anurans, so large males were not necessarily more attractive to females. Presence or absence of upper harmonics in the call had no effect on female choice. Tree holes with shallow air columns were more often used by calling frogs, and were presumably more common, than deep holes. Since male M. sundana actively exploit the resonant properties of tree holes for mate attraction, and high frequencies match comparatively shallow holes, the benefits of attaining acoustic matching probably select for high-frequency calls. In addition, males with high-frequency calls may be heard from a greater distance in the vicinity of torrent streams. Since the level of such noise in the forest varies in time and space, different frequencies may prove optimal in different contexts, thereby preserving the observed variation within the population. Having an 'unattractive' high-frequency call should be potentially beneficial only when calling males do not congregate, a condition that our data suggest is fulfilled in this system

    Use of arboreal and terrestrial space by a small mammal community in a tropical rain forest in Borneo, Malaysia

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    Aim: Small mammals were live-trapped in a primary rain forest to evaluate the relative distribution of species to each other and to microhabitat properties on the ground and in the canopy. Location: Kinabalu National Park in Borneo, Sabah, Malaysia. Methods: Seven trapping sessions were conducted along two grids with 31 trap points at distances of 20 m on the ground and in the lower canopy at an average height of 13.5 m. Results: Species diversity and abundance of small mammals proved to be high: 20 species of the families Muridae, Sciuridae, Tupaiidae, Hystricidae, Viverridae and Lorisidae were trapped, with murids being dominant in both habitat layers. The terrestrial community was significantly more diverse with 16 captured species (Shannon-Wiener's diversity index H0 terr 1/4 2.47), while 11 species were trapped in the canopy (H0 arb 1/4 1.59). The Whitehead's rat, Maxomys whiteheadi, and the red spiny rat, Maxomys surifer, dominated the terrestrial community whereas the large pencil-tailed tree mouse, Chiropodomys major, was by far the most abundant species in the canopy. Other abundant species of the canopy community, the dark-tailed tree rat, Niviventer cremoriventer, and the lesser treeshrew, Tupaia minor, were also abundant on the ground, and there was no clear boundary between arboreal and terrestrial species occurrences. Main conclusions: As most species were not confined to specific microhabitats or habitat layers, species seemed to rely on resources not necessarily restricted to certain microhabitats or habitat layers, and separation of species probably resulted mainly from a species' concentrated activity in a preferred microhabitat rather than from principal adaptations to certain habitats. Ecological segregation was stronger in the more diverse terrestrial community, though microhabitat selection was generally not sufficient to explain the co-occurrences of species and the variability between local species assemblages. Constraints on small mammal foraging efficiency in the three-dimensional more complex canopy may be responsible for the similarity of microhabitat use of all common arboreal species. Community composition was characterized by mobile species with low persistence rates, resulting in a high degree of variability in local species assemblages with similar turnover rates in both habitats.Konstans Wells, Martin Pfeiffer, Maklarin B. Lakim, and K. Eduard Linsenmai

    Shifts from native to invasive small mammals across gradients from tropical forest to urban habitat in Borneo

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    Urbanization has paved the way for the spread of commensal rodents at global scale. However, it is largely unknown how these species use tropical anthropogenic landscapes originally covered with forests and inhabited by diverse small mammal assemblages. We surveyed non-flying small mammals in various urban and suburban habitat types and adjacent forest in the tropical town of Kota Kinabalu in Borneo. We used occupancy and polynomial regression models to determine variation in species occurrences along gradients of land-use intensity. Müller’s sundamys (Sundamys muelleri) was the only native small mammal species found in urban and suburban landscapes with a continuous decrease in occurrence probability from forests to urban habitats. The invasive Asian black rat (Rattus rattus species complex) and the invasive Asian house shrew (Suncus murinus) had the highest occurrence probabilities in habitats of intermediate land-use intensity, but Asian black rats are also likely to occasionally invade forested habitats and occupied urban habitats in sympatry with the Norway rat (Rattus norvegicus). In urban and suburban habitats, fallow land possibly favoured the occurrence of S. muelleri and S. murinus. Other native small mammal species (Muridae, Sciuridae, Tupaiidae) were found only in forested areas. Our study shows that native small mammals found in forest are largely replaced by invasive species in urban and suburban habitats. Due to their occurrence in habitats of various land use intensities, S. muelleri and R. rattus comprise central links between forest wildlife and urban species, an association that is important to consider in studies of parasite and disease transmission dynamics.Konstans Wells, Maklarin B. Lakim, Robert B. O’Har

    New Species of Anomochilus from Borneo (Squamata: Anomochilidae

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    A new species of Anomochilus is described from Gunung Kinabalu Park, Sabah, Malaysia (Borneo). The new species is diagnosed from the only two other known species in the genus by the combination of the following character states: SVL to 509 mm; an azygous parietofrontal; paravertebrals 269; transverse body rows 17 : 19 : 17; midventrals 258–261; subcaudals 7–8; dorsum unpatterned dark brown, except for pale flecks, one scale wide, on paravertebral region; large pale blotches absent on dorsum; flanks without light line; and a pair of large pale blotches present on either side of venter. A dichotomous identification key to the three currently known species of Anomochilus is provided. With three species of Anomochilus known for Borneo, the island is the center of diversification of this genus of presumably fossorial and cryptozoic snakes

    A new species of Leptolalax (Anura: Megophryidae) from Borneo

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    Volume: 7Start Page: 48End Page: 5
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