Non-human primates have long been identified to harbour different species of Plasmodium. Long-tailed macaques (Macaca fascicularis), in particular, are reservoirs for P. knowlesi, P. inui, P. cynomolgi, P. coatneyi and P. fieldi. A previous study conducted in Sarawak, Malaysian Borneo, however revealed that long-tailed macaques could potentially harbour novel species of Plasmodium based on sequences of small subunit ribosomal RNA and circumsporozoite genes. To further validate this finding, the mitochondrial genome and the apicoplast caseinolytic protease M genes of Plasmodium spp. were sequenced from 43 long-tailed macaque blood samples. Apart from several named species of malaria parasites, long-tailed macaques were found to be potentially infected with novel species of Plasmodium, namely one we refer to as “P. inui-like.” This group of parasites bifurcated into two monophyletic clades indicating the presence of two distinct sub-populations. Further analyses, which relied on the assumption of strict co-phylogeny between hosts and parasites, estimated a population expansion event of between 150,000 to 250,000 years before present of one of these sub-populations that preceded that of the expansion of P. knowlesi. Furthermore, both sub-populations were found to have diverged from a common ancestor of P. inui approximately 1.5 million years ago. In addition, the phylogenetic analyses also demonstrated that long-tailed macaques are new hosts for P. simiovale. Malaria infections of long-tailed macaques of Sarawak, Malaysian Borneo are complex and include a novel species of Plasmodium that is phylogenetically distinct from P. inui. These macaques are new natural hosts of P. simiovale, a species previously described only in toque monkeys (Macaca sinica) in Sri Lanka. The results suggest that ecological factors could affect the evolution of malaria parasites.

Taste perception is an essential function that provides valuable dietary and sensory information, which is crucial for the survival of animals. Studies into the evolution of the sweet taste receptor gene (TAS1R2) are scarce, especially for Bornean endemic primates such as Nasalis larvatus (proboscis monkey), Pongo pygmaeus (Bornean orangutan), and Hylobates muelleri (Muller’s Bornean gibbon). Primates are the perfect taxa to study as they are diverse dietary feeders, comprising specialist folivores, frugivores, gummivores, herbivores, and omnivores. We constructed phylogenetic trees of the TAS1R2 gene for 20 species of anthropoid primates using four different methods (neighbor-joining, maximum parsimony, maximum-likelihood, and Bayesian) and also established the time divergence of the phylogeny. The phylogeny successfully separated the primates into their taxonomic groups as well as by their dietary preferences. Of note, the reviewed time of divergence estimation for the primate speciation pattern in this study was more recent than the previously published estimates. It is believed that this difference may be due to environmental changes, such as food scarcity and climate change, during the late Miocene epoch, which forced primates to change their dietary preferences. These findings provide a starting point for further investigation.

The family Ranidae of Sarawak frogs comprises the genera Hylarana, Pulchrana, Abavorana, Chalcorana, Staurois, Meristogenys, Odorrana, and Huia. Studies revealed that the advertisement call characteristics emitted by male frogs vary in different species. This study aims to describe the characteristics of the male frogs in the advertisement call and analyse the call characters that are useful for species discrimination. Field samplings were conducted to record the frog calls for the sound call characteristic analysis. The findings indicate that advertisement call characteristics could discriminate the frog species. Pulse duration, call energy, and call frequencies are among the useful characteristics that revealed a high correlation between dominant frequency and pulse duration and body size. The call properties are also useful in distinguishing individuals of the frog species among populations. In conclusion, this database will serve as a resource for future studies in understanding frog distribution and adaptation in their habitat.

Anuran skin preserves all functional activities, especially for respiration and water regulation. Duttaphrynus melanostictus and Fejervarya limnocharis are the common species found in Borneo lowlands and are well-adapted to humans. Hence, they can reproduce quickly and rapidly in great numbers in the urban area. This study aims to select these urban-type anurans and describe the skin structure and glands. Four regions of skin samples were obtained, namely Dorsal Head (DH), Dorsal Centre (DC), Ventral Head (VH) and Ventral Centre (VC). The microscopic slides were prepared accordingly as in the histological techniques including skin grossing, fixing, processing, embedding, sectioning and were stained with Haematoxylin and Eosin staining. The seromucous glands are most prevalent in all four regions for both species. Parotoid glands are clearly visible in the skin structure of D. melanostictus, while there is a lack of parotoid glands in F. limnocharis. Nonetheless, F. limnocharis contains regular rows of glands, whereas the distribution of glands in D. melanostictus is scattered. In addition, D. melanostictus possess dermal bones, which are absent in F. limnocharis. Since anuran skin is a mucosal surface that in constant direct contact with the environment, their adaptations to harsh habitats should be reflected in the skin, particularly in the urban and invasive species in this study.

Recent study has revealed that the poison gland in Odorrana hosii skin act as defensive mechanism and can help in wound healing management of a frog species. Since skin is the first organ that come into contact with the surrounding, the habitat of the species should be related to the properties of the frogs’ skin. Thus, we investigated the O. hosii skin histology in relation to water quality parameters at different localities in Sarawak. The goal of study is to uncover a link between O. hosii habitat and its skin histology at four different locations: Ranchan Recreational Park (RRP), Matang Wildlife Centre (MWC), Borneo Highlands (BH), and Santubong National Park (SNP). The water quality criteria for each area were pH, turbidity, temperature, and dissolved oxygen (DO). The results showed that DO concentration of the habitat is the most essential element in affecting the health of the amphibian skin, as well as the forested areas (MWC, SNP, and BH) that protect the skin from direct sunlight. The DO of the habitat differed significantly for the mean number of mucous and seromucous glands at 0.01 (α = 0.05) and 0.03 (α = 0.05), respectively. The number of mucous glands and DO were found to have a strong positive correlation at 0.701. However, the number of seromucous glands showed a strong negative correlation with DO at -0.623. O. hosii skin from the four different localities was found to have cutaneous gland variations that reflect the environment in the number of glands. Mucous glands play an important role in indicating the localities’ water quality, which reflects adaptation of O. hosii to its habitat. This highlights the importance of preserving natural habitats for this sensitive species.