Occurrence and ecological implication of a tropical anguillid eel, Anguilla marmorata, in Brunei Darussalam, Borneo Island

Tropical anguillid eels account for two-thirds of the 19 species in Anguilla Schrank, 1798. However, information on the species diversity, geographical distribution, and life histories of the tropical eels is very limited. Recent studies suggested that morphological species identification of the tropical anguillid eels should be validated by molecular analysis for accurate identification. After surveying for three years, two anguillid eels were found in Brunei Darussalam, Borneo Island. They were firstly identified as Anguilla marmorata Quoy & Gaimard, 1824 using morphological analysis and further gene analysis of cytochrome c oxidase subunit I (COI) confirmed the species identification. This study is the first comprehensive description of A. marmorata in Brunei Darussalam, Borneo Island. Furthermore, it is also the first study to validate two anguillid eels collected from the tropical Bonin Islands of Japan as A. marmorata by means of morphological and COI analyses. The molecular phylogenetic tree and haplotype network analyses suggest that A. marmorata found in Brunei Darussalam would belong to the North Pacific population of the westernmost distribution

Benthic community structure and ecosystem functions in above- and below-waterfall pools in Borneo

Waterfalls are geomorphic features that often partition streams into discrete zones. Our study examined aquatic communities, litter decomposition and periphyton growth rates for above- and below-waterfall pools in Ulu Temburong National Park, Brunei. We observed higher fish densities in below-waterfall pools (0.24 fish m−2 vs. 0.02 fish m−2 in above-waterfall pools) and higher shrimp abundance in above-waterfall pools (eight shrimp/pool vs. less than one shrimp/pool in below-waterfall pools). However, macroinvertebrate densities (excluding shrimp) were similar among both pool types. Ambient periphyton was higher in below-waterfall pools in 2013 (4.3 vs. 2.8 g m−2 in above-waterfall pools) and 2014 (4.8 vs. 3.4 g m−2 in above-waterfall pools), while periphyton growth rates varied from 0.05 to 0.26 g m−2 days−1 and were significantly higher in below-waterfall pools in 2014. Leaf litter decomposition rates (0.001 to 0.024 days−1) did not differ between pool types, suggesting that neither shrimp nor fish densities had consistent impacts on this ecosystem function. Regardless, this research demonstrates the varied effects of biotic and abiotic factors on community structure and ecosystem function. Our results have highlighted the importance of discontinuities, such as waterfalls, in tropical streams.</p

Macroinvertebrate trophic structure on waterfalls in Borneo

Waterfalls have unique physical characteristics and harbour highly specialised macroinvertebrate communities, but have been the subject of very few ecological studies. There are no previous studies of trophic structure of waterfall assemblages. It was hypothesised that because of the steep gradient of waterfalls and low retention of terrestrial-based resources, the abundant basal food resources would be periphyton. In addition, because of the frequent scouring flood events, it was predicted that periphyton would be a significant source of food for filter feeders. Waterfalls in the Ulu Temburong National Park (Brunei Darussalam) were used in the present case study. Methods included stable carbon (C)- and nitrogen (N)-isotope analyses (SIA; δ13C and δ15N of leaf litter and periphyton) and gut-content analysis (GCA) of the most the abundant macroinvertebrates. With δ15N values ranging from –1.9 to 5.5‰, literature suggests that this indicates that herbivores (Heptageniidae and Blephariceridae), omnivores (Simuliidae and Hydropsychidae) and predators (Buccinidae) live in the waterfalls. Apart from Buccinidae, the taxa had δ13C signatures ranging from –33 to –26‰, with a high dependence on periphyton, which is similar to other tropical-stream biotopes. The present study suggests that despite scouring velocities, waterfalls support animals with a range of diets, based on grazing or scraping, filter feeding and predation

FIGURES 17, 18 in Zorotypus asymmetricus sp. nov. from Brunei Darussalam, Borneo (Insecta: Zoraptera)

FIGURES 17, 18. Living status and occupied habitat of Zorotypus asymmetricus sp. nov. 17, living apterous male; 18, rotting logs in Sungai Esu stream valley where Z. asymmetricus sp. nov. was collected

Two new Oriental species of Paramanota Tuomikoski (Diptera: Mycetophilidae), with DNA sequence data

Hippa, Heikki, Kaspřák, David, Kahar, Siti Rafhiah Haji Abd, Ševčík, Jan (2016): Two new Oriental species of Paramanota Tuomikoski (Diptera: Mycetophilidae), with DNA sequence data. Raffles Bulletin of Zoology 64: 360-367, DOI: http://doi.org/10.5281/zenodo.535571

First record of Encheloclarias (Teleostei: Clariidae) from Brunei Darussalam with notes on the taxonomic status of E. baculum Ng & Lim, 1993, and E. prolatus Ng & Lim, 1993

The rare clariid catfish genus Encheloclarias is recorded for the first time from the peat swamp habitat in Brunei Darussalam, representing its northernmost record on the island of Borneo. Upon detailed examination, the Brunei species is keyed out to E. baculum. Using fresh material from Brunei and Sarawak (Malaysia, Borneo), the taxonomic status of E. prolatus is reviewed, and is herein synonymised with E. baculum, as first reviser’s action. An updated key for all Encheloclarias species is provided, and ecological notes on the Brunei material discussed.National Research Foundation (NRF)This project has been supported by the following agencies: the National Research Foundation Singapore through the Singapore-MIT Alliance for Research and Technology’s Center for Environmental Sensing and Modeling interdisciplinary research program and Grant No. NRF2019- ITC001-001. Research work done by THH is supported by the Lee Kong Chian Natural History Museum, National University of Singapore

Synonymy of Discotettix adenanii Mahmood, Idris & Salmah, 2007 with D. belzebuth (Serville, 1838) (Orthoptera: Tetrigidae)

Kočárek, Petr, Kuřavová, Kateřina, Musiolek, David, Wahab, Rodzay Abdul, Kahar, Siti Rafhiah Abdul (2015): Synonymy of Discotettix adenanii Mahmood, Idris & Salmah, 2007 with D. belzebuth (Serville, 1838) (Orthoptera: Tetrigidae). Zootaxa 4057 (2): 288-294, DOI: http://dx.doi.org/10.11646/zootaxa.4057.2.1