The Amphibians, Reptiles and Fishes of the 2012 Bukit Pagon Expedition, Brunei Darussalam

The Amphibians, Reptiles and Fishes of the 2012 Bukit Pagon Expedition, Brunei Darussalam Hanyrol H. Ahmad Sah 1, T. Ulmar Grafe 1, Alex Dornburg 2, David S. McLeod 3, Aaron M. Bauer 4, Rodzay Abdul Wahab 5, Lee Grismer 6 and Gregory J. Watkins-Colwell 7 1 Faculty of Science, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Brunei Darussalam 2 North Carolina Museum of Natural Sciences, Raleigh, NC 27601 USA 3 Biology Department, James Madison University, Harrisonburg, VA 22801 USA 4 Department of Biology, Villanova University, 800 Lancaster Avenue, Villanova, PA 19085 USA 5 Institute for Biodiversity and Environmental Research, Universiti Brunei Darussalam, Jalan Tungku Link, BE1410, Brunei Darussalam 6 Department of Biology, La Sierra University, 4500 Riverwalk Parkway, Riverside, CA 92515 USA 7 Corresponding author: Yale Peabody Museum of Natural History, P. O. Box 208118, New Haven, CT 06520-8118 USA email: gregory.watkins-colwell@yale.edu ABSTRACT In July 2012, 22 people representing eight institutions from six countries conducted a six-day expedition to the submontane heath forest near Bukit Pagon in Brunei Darussalam. Base camp was located at an elevation of 862 masl about 200 m from the Brunei-Sarawak border and 9 km from the peak of Bukit Pagon. The herpetology and ichthyology portion of the survey resulted in the collection of 61 specimens, representing 30 species, with 4 additional species documented by photograph but not collected. One additional taxon, Tropidophorus brookei, was seen but neither collected nor photographed. Nearly half of the species found are endemic to Borneo. The findings of this brief expedition shed light on the distribution of many endemic taxa in one of the world s greatest biodiversity hot spots. Despite its small size, Brunei supports a rich vertebrate fauna that is understudied compared with neighboring Sarawak and nearby Sabah. KEYWORDS Brunei Darussalam, Bukit Pagon, amphibian, reptile, Protomyzon, Leiocassis, Limnonectes, Hylarana, checklist ABSTRAK (MALAY) Pada bulan Julai 2012, 22 orang yang mewakili lapan buah institusi dari enam buah negara telah melakukan ekspedisi selama enam hari di hutan kerangas submontane berhampiran Bukit Pagon di Negara Brunei Darussalam. Tapak perkhemahan terletak pada ketinggian 862 m di atas paras laut, lebih kurang 200 m dari sempadan Brunei-Sarawak dan 9 km dari puncak Bukit Pagon. Dari tinjauan bahagian herpetologi dan perikanan, sejumlah 61 spesimen yang mengandungi 30 spesies telah diperolehi, dengan empat spesies tambahan yang hanya didokumenkan melalui gambar tetapi tidak diambil. Satu takson tambahan, Tropidophorus brookei, telah kelihatan tetapi tidak diambil atau digambar. Hampir separuh daripada spesies-spesies yang ditemui adalah endemik ke Borneo. Hasil ekspedisi singkat ini memberi penerangan mengenai pengagihan banyak taksa endemik di salah satu tempat biodiversiti terbesar di dunia. Walaupun bersaiz kecil, Brunei menpunyai pelbagai jenis fauna vertebrata yang kurang dikaji berbanding dengan Sarawak dan Sabah. KATA KUNCI Brunei Darussalam, Bukit Pagon, amfibia, reptilia, Protomyzon, Leiocassis, Limnonectes, Hylarana, senarai semak Bulletin of the Peabody Museum of Natural History 57(1):97 114, April 2016. 2016 Peabody Museum of Natural History, Yale University. All rights reserved. http://peabody.yale.edu

98 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 Introduction The tropical forests of Southeast Asia are home to some of the planet s most diverse flora and fauna while simultaneously facing some of the most pressing conservation concerns of the 21st century (Sodhi et al. 2004; Koh and Wilcove 2008). Over the past several decades, deforestation and other environmental changes have increasingly threatened the future of these species (Curran et al. 2004; Miettinen et al. 2011). As logging pressure continues to increase, the forests of Borneo have risen to the forefront in discussions of how to sustainably manage the competing needs of wildlife and industry in Southeast Asia (Meijaard et al. 2005; Rautner et al. 2005; Berry et al. 2010). However, sustainable management of the earth s third-largest island requires a comprehensive understanding of both species richness and the spatial distribution of these species. Unfortunately, even in well-studied areas, such information is often lacking for taxa that are not easily observed, such as reptiles, amphibians and fishes (Gibbons et al. 2000; Dornburg et al. 2009). Efforts to catalog Borneo s ichthyological and herpetological diversity have been ongoing for more than a century (Günther 1872, 1874; Boulenger 1891; Smith 1925, 1931; Inger and Voris 1993; Inger and Lian 1996; Das 2004a; Matsui and Nishikawa 2014). Despite this prolonged period of study, the pace of species discovery has remained rapid (Hee 1999; Hui 2006; Britz and Kottelat 2008; Matsui et al. 2010, 2014; Das et al. 2014; Dehling 2015; Eto et al. 2015) and led to the consensus that the biodiversity of the island continues to be underdescribed (Inger and Stuebing 2009). Similarly, our understanding of the spatial distribution of described species remains limited, and the fragmentary geographic scope of biological surveys still remains one of the biggest roadblocks to Southeast Asian conservation biology (Rowley et al. 2010). Here we contribute to the survey efforts of Borneo by providing the results of a multi-institutional survey effort in the country of Brunei Darussalam. Brunei Darussalam is the smallest country on the island of Borneo, with a total surface area of 5,765 km 2 and a human population of approximately 416,000 (Roberts 2014). This nation is among the wealthiest in the world and has managed to maintain a large percentage of its land as undeveloped (Sodhi et al. 2004). However, increased demand for tropical wood and wildlife has brought attention to conservation concerns, especially along the nation s borders with Malaysia where lumbering activities are known to cross the border into Brunei (Gaveau et al. 2014). It was with these conservation concerns in mind that the Universiti Brunei Darussalam (UBD), with the Brunei Forestry Department, initiated the first multinational expedition to survey the biodiversity near the nation s tallest peak, Bukit Pagon, which rises to a height of 1,850 m along the Malaysian border (Figure 1). In July 2012, 22 people representing eight institutions from six countries convened at UBD for an organized six-day expedition to the submontane heath forest near Bukit Pagon where they were joined by Forestry Department Herbarium (BRUN) staff, students and faculty members from UBD (Table 1). The expedition was organized under the icube (International Consortium of Universities for the Study of Biodiversity and the Environment) Initiative, and coorganized by UBD, Brunei Forestry Department and Ministry of Industry and Primary Resources (now Ministry of Primary Resources and Tourism). The expedition was staged in an area along the Temburong River, from which the expedition to Bukit Pagon was airlifted by the Royal Brunei Armed Forces to the base camp. The location of the Bukit Pagon Expedition base camp was set up at an elevation of 862 masl, about 200 m away from the Brunei- Sarawak border and about 9 km from the peak of Bukit Pagon. The group surveyed the general biodiversity of the region with a focus on select groups (birds, amphibians, reptiles, fish, plants and insects) and additionally conducted studies of stream ecology and tree shrew ecology. Here we present the results of the herpetological and ichthyological portion of this expedition. Methods Daily excursions, both diurnal and nocturnal, were made along streams and logging roads located near base camp (Figure 1). Specimen collection methods varied, although most specimens were captured by hand, with a snake hook or a small handheld dip net. Along one creek site, drift fencing and funnel-style minnow traps were also used. All photo vouchers were photographed

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 99 FIGURE 1. Map of Brunei Darussalam with detail of base camp location and nearby mountain peaks.

100 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 TABLE 1. Institutions and number of representatives contributing to the icube (International Consortium of Universities for the Study of Biodiversity and the Environment) survey. Name Affiliation Research project title Yoon Tae Kyung* Korea University, CO 2 efflux from soil surface in and Saerom Han* Korea Mt. Pagon Claas Damken* Auckland University, Comparison of species traits of a New Zealand functional guild along ecological gradients using combined data sets Shelley Myers* Auckland University, Diversity of Phasmatodea New Zealand on Mt. Pagon Tajang Jinggut* Monash University, Leaf litter decomposition in tropical Australia montane streams, a study of biodiversity and ecosystem functioning Lee Jo Kien* Monash University, A pilot study of montane soil Australia carbon respiration and soil properties of Mt. Pagon, Brunei Kristof Zyskowski Yale University, United States A rapid assessment of the avifauna of Mt. Pagon Gregory Watkins-Colwell Yale University, United States Amphibian, reptile and fish systematics and biogeography Kate Baker* Kings College London, Macroinvertebrate biodiversity in United Kingdom tropical streams Timothy Motley Old Dominion University, Systematic studies of the Rubiaceae, United States Loganiaceae and other Asteridae lineages Brunei National Herbarium Forestry Department, Collection of plants to be deposited (BRUN), head: Brunei Darussalam in BRUN Awg Joffre Hj Ali Ahmad Dato Haji Mohamed Haji Universiti Brunei Project 1: the composition and Abdul Majid, Saabiqah Abd. Darussalam distribution of bryophytes in Montane Salam* and Liaw Lin Ji* Forest of Brunei Darussalam; project 2: preliminary findings on the distribution of ferns in Mt. Pagon Rahayu Sukmaria Haji Sukri Universiti Brunei Plant species diversity and richness and Sheikh Hj Husrin Jairul Darussalam along an altitudinal gradient at Nazry Sheikh Hj Hassan* Mt. Pagon, Brunei Aline Barbara Horwath Universiti Brunei Darussalam Epiphytic bryophytes as indicators of elevational and climatic zonation on Mt. Pagon (Brunei Darussalam) Rodzay Haji Abdul Wahab Universiti Brunei Darussalam Project 1: a survey of the soil macroarthropods in Mt. Pagon; project 2: a survey of the Odonata of Mt. Pagon Siti Rafhiah Haji Abdul Kahar Universiti Brunei Darussalam Terrestrial insect biodiversity survey in the tropical montane forest, Mt. Pagon (Brunei Darussalam) Siti Salwa Abdul Khalid* Universiti Brunei Darussalam Nonvolant small mammal species richness of Bukit Pagon, Brunei Darussalam Jeffery Ang Meng Ann* Universiti Brunei Darussalam Nonvolant small mammal species richness of Bukit Pagon, Brunei Darussalam Hanyrol Ahmad Sah* Universiti Brunei Darussalam Inventory of amphibians and reptiles at Bukit Pagon, Brunei Darussalam Liaw Lin Ji* Universiti Brunei Darussalam Measuring ant diversity on Bukit Pagon, Temburong * Indicates that the participant was a student at the time.

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 101 FIGURE 2. Percent of encounters representing species endemic to Borneo by day. using a Cannon 450D camera with 60 mm macro lens. Most specimens were preserved in 10% buffered formalin (later transferred to 70% ethanol) with tissue biopsies for DNA analyses preserved in either ethanol or RNAlater. Some specimens, especially tadpoles and fish, were prepared in 70% ethanol in the field. Attempts were made to sequence muscle tissue obtained from tadpoles (Leptobrachella and Limnonectes) and some adult anurans (e.g., Limnonectes cf. kuhlii), but these were unsuccessful, possibly due to tissue degradation in the field. Specimens were deposited in the Yale Peabody Museum of Natural History (YPM) and the collection at UBD. All taxonomies and common names provided are from standard names indices for fishes (Eschmeyer and Fricke 2015), amphibians (Frost 2015) and reptiles (Uetz and Hallermann 2015). In the case of amphibians, we retain the genus name Hylarana (sensu lato) and reject the splitting of this monophyletic genus as proposed by Oliver et al. (2015). However, the new genera are given in brackets under the species descriptions. Common names are provided only for determinations at species level. Developmental stages of anuran larvae were determined using Gosner (1960). The labial tooth row formulas (LTRFs) follow that of Altig and McDiarmid (1999). Results Natural history information provided for each taxon (subsequent sections) is based on personal observations made by the authors. A total of 61 specimens, representing 30 species, were collected with 4 additional species documented by photograph but not collected. One additional species (Tropidophorus brookei) was identified in the field, but neither photographed nor collected. Amphibians represent the broadest taxonomic diversity that we collected, representing 23 taxa in seven families. Excluding unidentified larvae, Polypedates macrotis (N 7) was the most frequently encountered. Hylarana picturata and Limnonectes kuhlii were also encountered frequently and are each represented by 5 specimens. Reptiles were less frequently observed, though we managed to sample 8 taxa representing seven families, including photo vouchers. Many additional Eutropis species were encountered, but these were neither collected nor photographed. During four of the six days spent surveying, more than 40% of the reptile and amphibian species encountered were Bornean endemics (Figure 2). Coordinates for collecting sites are indicated (see Table 2).

102 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 TABLE 2. Coordinates for collecting sites. Coordinates are from handheld Garmin GPS using WGS-84 datum except for those indicated with an asterisk, which are approximations using GoogleEarth (also with WGS-84 datum). Description Latitude Longitude icube Base Camp: logging road between 4.339742 115.261787 drop-off and stream (LP061)* On logging road between icube Base 4.339179 115.262388 Camp and stream 61a (LP061)* icube Base Camp 4.3433 115.2611 On ground near puddles along the logging road 4.3381 115.2622 near latrine Puddles along the logging road near latrine 4.337 115.26178 Ravine with sedges on logging trail near base camp 4.33614 115.26153 Stream 61 (LP061) near main trail 4.34158 115.26036 Stream 61 near waterfall 4.34344 115.26106 Stream 61a 4.3405 115.26042 Stream 61a near main trail 4.3417 115.2603 Top of hill with sedges on logging road at edge 4.33586 115.26131 of base camp * Approximations using GoogleEarth (with WGS-84 datum). Fishes CYPRINIFORMES: BALITORIDAE Protomyzon Hora, 1932 Material. YPM ICH 025829. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61 near waterfall; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol and tissue in ethanol; 3 July 2012. YPM ICH 025830-025831. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a; collectors: G.J. Watkins-Colwell and K. Baker; 5 July 2012. Vouchers retained at UBD (see Figure 3). Tissue in RNAlater at YPM. Comments. Protomyzon are among the more common of fishes in Borneo (Rahim et al. 2002), where they replace cyprinids in undisturbed high-elevation streams (Nyanti et al. 1995; Kavanagh 2002). These fishes are morphologically adapted to keep their position in swift flowing water; however, little is known about their ecology, evolution or total species diversity. Though surveys have been limited, there is at least one undescribed species of Protomyzon in Brunei (Choy and Chin 1994; Parenti and Meisner 2003). It is quite likely that the diversity of this genus is underestimated. These fishes have been found both above and below waterfall areas (Choy and Chin 1994) that can potentially act as barriers to gene flow (Castro et al. 2014), an observation that when coupled with the hypothesis that northern Borneo represent a unique biogeographic province (Yap 2002), supports this conclusion of underdescribed species richness. As Brunei s fishes face challenges such as habitat loss, pollution and changes in flow regimes (Chong et al. 2010), as well as introductions of exotic fishes (Kavanagh 2002), further survey efforts and studies are desperately needed to understand the biodiversity of these taxa. SILURIFORMES: BAGRIDAE Leiocassis Bleeker, 1857 Material. YPM ICH 025832. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61 (LP061) near main trail; collector: G.J. Watkins-Colwell; 5 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). Comments. Identification of the specimen has proved problematic. The specimen is stored in 95% ethanol at UBD. Although the storage fluid will facilitate molecular analysis, it resulted in significant shrinkage of the specimen, including features such as adipose fin and barbels. A BLAST (Basic Local Alignment Search Tool) search of the bar code gene COI from a tissue sample stored in RNAlater against data deposited in GenBank and the Barcode of Life database revealed many possible species identifications, none of which are within Siluriformes. The closest matches shared only 85% identity with our sequence, Acrossocheilus hemispinus or Gyrinocheilus aymonieri, though dozens of additional species were within 1% of this identity. Prior to preservation, the specimen had a clear adipose fin and barbels and seemed to lack scales. The mouth is terminal or just subterminal and does not form a sucker. We maintain the field identification of Leiocassis sp., though it may be some other member of Bagridae. The lack of resolution with the COI bar code identification could potentially represent an instance of low coverage of Bornean catfishes on the two queried databases. It is possible that DNA degradation or contamination could be involved; for example, DNA from another species could have been present on the sur-

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 103 FIGURE 3. Photographs of specimens retained as vouchers at UBD. A, YPM HERA 013739 Ansonia longidigita. B, YPM HERA 013745 Hylarana (Pulchrana) picturata. C, YPM HERA 013751 Polypedates macrotis. D, YPM HERA 013759 Rentapia rugosus. E, YPM HERA 013760 Limnonectes paramacrodon. F, YPM HERA 013761 Meristogenys poecilus. G, YPM HERA 013764 Rhacophorus rufipes. H, YPM ICH 025830 Protomyzon. I, YPM ICH 025831 Protomyzon. J and K, YPM ICH 025832 Leiocassis. face of the fish (e.g., edna; Jerde et al. 2011; Minamoto et al. 2012; Miya et al. 2015) prior to collection of the sample and then amplified. However, given the low affinity of our sample to reference samples, we find this unlikely. Given the clear morphological affinity of the specimen, we view the present case as an example of the importance of voucher specimens for molecular studies. Specimen vouchers are a fundamental component of the initiative to bar code all fishes (Ward et al. 2005; Miller 2007; Ward et al. 2009), and voucher repositories, such as the natural history collections contributing to this study, are tasked with maintaining this important reference collection. In the case of this specimen, future survey efforts will enable a comparison of both the phenotype and genotypes of additional individuals. More broadly, as we move into the 21st century, vouchers will be critical to ensuring the accuracy of ecological, spatial and environmental data associated with each specimen, forming the foundation of our description of the planet s biodiversity and informed conservation practices (Pyke and Ehrlich 2010). Amphibians ANURA: BUFONIDAE Ansonia longidigita Inger, 1960 Long-fingered Slender Toad Material. YPM HERA 013737. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in RNAlater; 2 July 2012. YPM HERA 013739. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 2 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see

104 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 Figure 3). YPM HERA 013738. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol and tissue in RNAlater; 4 July 2012. Comments. This is a large stream toad with elevated and spiny dorsal warts and maximum size of 70 mm snout-to-vent length (SVL; Inger et al., forthcoming). Adults live on the forest floor but are occasionally seen sitting on leaves of understory plants. Breeding takes place in clear, rocky streams near rapids. The diet consists mostly of ants and other small arthropods. Tadpoles live clinging to rocks in swift currents (Inger and Stuebing 2005). The species is a Bornean endemic widespread throughout the island. Ansonia platysoma Inger, 1960 Flat-bodied Slender Toad Material. YPM HERA 013730. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: H.H. Ahmad Sah; preparation type: 70% alcohol; 7 July 2012. Comments. Ansonia platysoma is a small, delicate toad with a distinctly flattened body and head. The maximum size is 25 mm SVL (Inger and Stuebing 2005). Males can be heard calling from steep, rocky, narrow streams in lowland and submontane rainforests usually surrounded by or close to waterfalls. Tadpoles cling to rocks in strong to medium currents and graze on algae (Inger et al., forthcoming). This species has been underreported in many surveys due to its similarity with A. albomaculata, and thus it is probably more widespread than currently appreciated. Rentapia rugosus (Inger, 1958) Marbled Tree Toad Material. YPM HERA 013759. Collected approximately 9 km northwest of the peak of Bukit Pagon: ravine with sedges on logging trail near base camp; collector: G.J. Watkins-Colwell; 4 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). Comments. This is a large tree toad with oval parotoid glands and bright green dorsal coloration with reddish brown spots. The maximum size is 95 mm SVL, and it occurs in hilly primary forests up to 1,050 masl (Inger and Stuebing 2005). Adults are arboreal but descend to rocky streams to breed. Southeast Asian Pedostibes is now placed in the new genus Rentapia named after the Iban warrior Rentap (Chan et al. 2016). Phrynoidis juxtaspera (Inger, 1964) Giant River Toad Material. YPM HERA 013763. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 4 July 2012. Comments. This is a very large, dark toad with warty skin. Females can reach a size of 215 mm SVL (Inger and Stuebing 2005). Adults live on the forest floor, going to fast-flowing streams to breed. It is an ant and termite specialist with a preference for large ants (Konopik et al. 2014a). Indeed, the stomach of YPM HERA 013763 contained many ants. Phrynoidis juxtaspera is found throughout Borneo in primary and old secondary forests up to 1,600 masl (Inger and Stuebing 2005). ANURA: DICROGLOSSIDAE Limnonectes Fitzinger, 1843 Tadpoles Material. YPM HERA 013774 (Gosner stage 30), YPM HERA 013782 (Gosner stage 25), YPM HERA 013783 (Gosner stage 26). Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol; 2 July 2012. YPM HERA 013775 (Gosner stage 36). Collected approximately 9 km northwest of the peak of Bukit Pagon: puddles along the logging road near latrine; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol; 3 July 2012. Comments. Tadpoles of Limnonectes generally have dorsoventrally flattened bodies and long slender tails with low fins that possess either dark bars or blotches. The LTRF for several species is 2(2)/3(1). Limnonectes cf. kuhlii (Tschudi, 1838) Material. YPM HERA 013747 13750. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 4 July 2012. YPM HERA 013746. Collected approximately 9 km northwest of the peak of Bukit Pagon: puddles along the logging road near latrine; collector: K. Zyskowski; 5 July 2012. Comments. A short, stocky frog with a tympanum that is partially or completely hidden by skin. Maximum size 67 mm SVL (Inger and Stuebing 2005). The Bornean frogs of the Limnonectes kuhlii complex represent a monophyletic clade comprising at least nine unique evolutionary lineages (candidate species) and probably more (McLeod 2010). True L. kuhlii is restricted to the island of Java (Iskandar 1998; McLeod 2010). Adult males have hypertrophied heads and jaw muscles, as well as enlarged odontoids ( fangs ) on the mandible. Adults live along rocky streams with moderate currents up to 1,600 masl (Inger and Stuebing 2005). Tadpoles are often found buried in the sandy substrate of streams during the daytime and emerge at night to feed. Limnonectes paramacrodon (Inger, 1966) Lesser Swamp Frog Material. YPM HERA 013760. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 4 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). Comments. A medium-sized frog with distinct dark brown tympanum. Maximum size 75 mm SVL (Das et al. 2008). Widely distributed throughout Borneo, it is usually associated with lowland forests and peat swamps.

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 105 Occidozyga cf. laevis (Günther, 1858) Yellow-bellied Puddle Frog Material. YPM HERA 013762. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 4 July 2012. Comments. A small frog with short, fat hind limbs and dorsally positioned eyes. It is well camouflaged in muddy water. It lives on the floor of lowland forests in puddles and seepage areas. Body size reaches 48 mm SVL (Inger and Stuebing 2005). ANURA: MEGOPHRYIDAE Leptobrachella Smith, 1925 Tadpoles Material. YPM HERA 013732. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collector: H.H. Ahmad Sah; preparation type: 70% alcohol; 7 July 2012. Comments. These tiny frogs are endemic to Borneo with seven species recorded (Inger et al., forthcoming). They have smooth skin and are smaller than 25 mm SVL (Inger and Stuebing 2005). All species occur in rainforest environments 150 2,200 masl (Inger and Stuebing 2005). However, only two species, Leptobrachella baluensis and L. brevicrus, are found above 900 m (Inger and Stuebing 2005). Leptobrachium Tschudi, 1838 Tadpoles Material. YPM HERA 013777 (Gosner stage 25). Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a; collectors: G.J. Watkins-Colwell and K. Baker; preparation type: 70% alcohol; 5 July 2012. YPM HERA 013778 (Gosner stage 26), YPM HERA 013779 (Gosner stage 25), YPM HERA 013780 (Gosner stage 26), YPM HERA 013781 (Gosner stage 26). Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near waterfall; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol; 3 July 2012. Comments. Leptobrachium tadpoles are large-bodied (more than 70 mm in total length) rocky stream dwellers. Leptobrachium tadpoles superficially resemble those of Limnonectes sp. but can easily be identified by the structure of the oral disc, which is completely surrounded by papillae and has six to seven rows of upper keratodont and five to six rows of lower labial keratodonts. Body is oval, spiracle at midbody, with dark bars on both body and tail. The mouth is subterminal with robust jaw sheaths. LTRF of YPM HERA 013777 is 7(2 7)/6(1 5) with eight short inframarginal ridges of keratodonts on the lower labium. Leptobrachium abbotti (Cochran, 1926) Lowland Litter Frog Material. YPM HERA 013731. Collected approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collector: H.H. Ahmad Sah; preparation type: 70% alcohol; 7 July 2012. Comments. All litter frogs of this genus are moderate sized with head slightly wider than body. The lowland species is typically considered to be Leptobrachium abbotti, and this specimen had a belly with bold black-and-white mottling typical for L. abbotti. Additional montane and lowland species have recently been described (Inger et al., forthcoming). The genus is likely to undergo further taxonomic revision with seven species currently recognized from Borneo (Inger et al., forthcoming). Adults and juveniles live on the forest floor. Adults migrate to small streams to breed where they lay their eggs in quiet pools. The tadpoles feed on dead vegetation (Inger and Stuebing 2005). ANURA: MICROHYLIDAE Chaperina fusca Mocquard, 1892 Saffron-bellied Frog Material. YPM HERA 013733. Collected approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collector: H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in ethanol; 7 July 2012. Comments. A tiny leaf-litter frog that is locally abundant. Dorsum is greenish black; the venter has a network of bright yellow spots. Maximum size 24 mm SVL (Inger and Stuebing 2005). Adults breed in temporary pools on the forest floor. Tadpoles feed on aquatic microorganisms. In Brunei, the diet of adults consists mostly of ants, mites, beetles and springtails, in that order of importance. Kalophrynus Tschudi, 1838 Material. YPM HERA 013735. Collected approximately 9 km northwest of the peak of Bukit Pagon: puddles along the logging road near latrine; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol and tissue in RNAlater; 4 July 2012. YPM HERA 013736. Collected approximately 9 km northwest of the peak of Bukit Pagon: puddles along the logging road near latrine; collectors: K. Zyskowski and H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in ethanol; 7 July 2012. Comments. Small leaf-litter frogs with a pointed snout and short, slender hind legs. Ten species are known to occur in Borneo (Inger et al., forthcoming). Body size of YPM HERA 013735 (19 mm) and YPM HERA 013736 (28 mm) is smaller than that of the larger species, which can be up to 57 mm SVL. Their diet consists mostly of ants and termites. When handled, they secret a sticky liquid as a defense. Tadpoles of most species are unknown, but those of Kalophrynus meizon are gray to olive in coloration, egg-shaped with a blunt tip to the tail and probably endotrophic (Inger and Stuebing 2005). ANURA: RANIDAE Hylarana (Abavorana) luctuosa (Peters, 1871) Mahogany Frog Material. YPM HERA 013758. Collected approximately 9 km northwest of the peak of Bukit Pagon: top of hill with sedges on

106 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 logging road at edge of base camp; collector: K. Zyskowski; 4 July 2012. YPM HERA 013776 (Gosner stage 28). Collected approximately 9 km northwest of the peak of Bukit Pagon: puddles along the logging road near latrine; collector: G.J. Watkins- Colwell; preparation type: 70% alcohol; 3 July 2012. Comments. A robust, medium-sized frog with a conspicuous reddish brown dorsal coloration separated by a white stripe from the black side of the head and trunk. Maximum size of individuals is 60 mm SVL (Inger and Stuebing 2005). Males are known to excavate small depressions at the edges of small pools or wallows from which they call (Inger and Stuebing 2005). Tadpoles of Hylarana luctosa live in ponds or slow-moving sections of streams. Spiracle is closer to snout than tail. Mouth is subterminal and has a complete row of small papillae around the lower labium and larger, elongated papillae laterally. LTRF of the examined specimen is 4(2 4)/5. Hylarana (Pulchrana) picturata (Boulenger, 1920) Spotted Stream Frog Material. YPM HERA 013741 013742. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; preparation type: 70% alcohol and tissue in RNAlater; 4 July 2012. YPM HERA 013745. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 2 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). YPM HERA 013744. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 3 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). YPM HERA 013743. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near waterfall; collectors: G.J. Watkins-Colwell, S. Myers and C. Damken; preparation type: 70% alcohol and tissue in RNAlater; 3 July 2012. Comments. A small to medium-sized frog. Juveniles and subadults live in the forest leaf litter, while adults come to breed in pools of rainforest streams and remain there throughout the year. Maximum size 70 mm SVL (Das 2007). Males call along the overhanging banks of streams during periods when water levels are low. Widely distributed throughout Borneo at elevations from 150 to 750 masl (Inger et al., forthcoming). This species was frequently encountered near streams around base camp. Meristogenys poecilus (Inger and Gritis, 1983) Pied-leg Torrent Frog Material. YPM HERA 013761. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 4 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). Comments. A medium-sized frog with long legs. Underside of legs whitish, without dark spots. Found in southeastern Sarawak and Brunei in forested, hilly terrain. Maximum size of individuals is 78 mm SVL (Das 2007). Tadpoles have an abdominal sucker allowing them to live in very strong currents. Odorrana hosii (Boulenger, 1891) Poisonous Rock Frog Material. YPM HERA 013740. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 4 July 2012. Comments. A large frog that inhabits the banks of creeks and rivers in primary forests. Maximum body size is 100 mm SVL (Inger and Stuebing 2005). Top of head and dorsum of body dark green in color. Known to inhabit forests up to 750 masl (Inger and Stuebing 2005). Staurois guttatus (Günther, 1858) Black-spotted Foot-flagging Frog Material. YPM HERA 015893. Photographed approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collector: H.H. Ahmad Sah; preparation type: photographic voucher; 3 July 2012. YPM HERA 013765. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near waterfall; collectors: G.J. Watkins-Colwell, S. Myers and C. Damken; 3 July 2012. YPM HERA 013766. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near waterfall; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: 10% formalin, transferred to 70% alcohol and tissue in RNAlater; 3 July 2012. Comments. A small frog with a pointed snout and slender limbs. Maximum size 55 mm SVL (Inger and Stuebing 2005). Diurnal frogs found aggregated near waterfalls and steep sections of medium-sized streams (e.g., 4 6 m wide). Males and females perform conspicuous foot-flagging displays in defense of territories and during courtship (Grafe and Wanger 2007). This species occurs in lowland forests in hilly terrain throughout most of Borneo. ANURA: RHACOPHORIDAE Feihyla kajau (Dring, 1983) White-eared Tree Frog Material. YPM HERA 013734. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: H.H. Ahmad Sah; preparation type: 70% alcohol; 7 July 2012. Comments. A very small tree frog with a white tympanum. Dorsal surfaces are green with small white spots The webbing of the toes is black. Maximum size 22 mm SVL (Inger et al., forthcoming). Aggregations of calling males can be found at small rivulets in hilly terrain of pristine forests up to 750 masl (Inger and Stuebing 2005). Eggs are deposited on the underside of leaves over pools of water without the foam nest common to other rhacophorids.

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 107 Philautus sp. Gistel, 1848 Early stage metamorph (Gosner stage 43) Material. YPM HERA 015340. Photographed approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collector: H.H. Ahmad Sah; preparation type: photographic voucher; 7 July 2012. Photographs show fully formed froglet still inside the egg. Comments. The Bornean Philautus inhabits primary and secondary forests, from near sea level to above 3,000 m. Twenty species are currently recognized from Borneo (Inger et al., forthcoming). Most species are found at higher elevations. Most Philautus species lack the typical anuran free-swimming tadpole, instead exhibiting direct development from embryo into tiny froglets. Philautus hosii (Boulenger, 1895) Hose s Bush Frog Material. YPM HERA 013784. Collected approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in RNAlater; 5 July 2012. YPM HERA 013785 013787. Collected approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: 70% alcohol; 5 July 2012. Comments. A large bush frog with a sharp-edged snout. Maximum size 63 mm SVL (Inger and Stuebing 2005). Yellowish sandy brown with a dark X-shaped mark on the back (hourglass pattern). Inhabits primary or old-growth secondary forests up to 600 masl (Inger and Stuebing 2005). Males call from understory vegetation near streams in hilly terrain. Polypedates macrotis (Boulenger, 1891) Dark-eared Tree Frog Material. YPM HERA 013751. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 2 July 2012. Voucher retained at UBD. Tissue in RNAlater at YPM (see Figure 3). YPM HERA 013752. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 2 July 2012. YPM HERA 013753 013755. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins- Colwell; 4 July 2012. YPM HERA 013756. Juvenile, collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp: logging road between drop-off and stream (LP061); collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in RNAlater; 5 July 2012. YPM HERA 013757. Collected approximately 9 km northwest of the peak of Bukit Pagon: ravine with sedges on logging trail near base camp; collector: G.J. Watkins-Colwell; 5 July 2012. Comments. A large tree frog with brown tympana. Maximum size 90 mm SVL (Das 2007). Inhabits primary and disturbed lowland forests. Often seen breeding in large aggregations in pools or ponds. Foam nests are attached to leaves above the water surface. Rhacophorus rufipes Dring, 1983 Red-legged Tree Frog Material. YPM HERA 013764. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: tissue in RNAlater; 2 July 2012. Comments. A small tree frog with red webbing between fingers. Upper surface of body is reddish brown. Inhabits primary forests below 900 masl (Inger et al., forthcoming). Uses small temporary puddles to breed. Foam nests are attached to leaves above the water surface or at the edge of small water bodies. GYMNOPHIONA: ICHTHYOPHIIDAE Ichthyophis nigroflavus Taylor, 1960 Yellow-black Caecilian Material. YPM HERA 015329. Photographed approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collector: H.H. Ahmad Sah; preparation type: photographic voucher (Figure 4); 5 July 2012. Comments. Very little is known about the habits and habitat of this caecilian. It is known to occur in tropical rainforests, where the adults live mostly below ground. It is presumed to be oviparous with terrestrial eggs and aquatic larvae (Das 2007). Reptiles SQUAMATA: AGAMIDAE Gonocephalus grandis (Gray, 1845) Giant Angle-headed Lizard Material. YPM HERR 018590. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 4 July 2012. Comments. A relatively large (to 160 mm SVL males, 137 mm SVL females) arboreal lizard with a long tail (to 2.9 times SVL) and striking sexual dimorphism (Malkmus et al. 2002). Adult males bear an enlarged dorsal crest and an enlarged dewlap and have a bright green dorsum and a blue venter and lower flanks spotted with yellow. Juveniles and females lack the ornamentation and are predominantly brown with a banded pattern. The species is typically associated with streamside habitats. During the expedition, two juveniles were seen at night, resting on branches near streams. Only one was collected. SQUAMATA: NATRICIDAE Hebius flavifrons (Boulenger, 1887) White-nosed Keelback

108 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 FIGURE 4. Photographic vouchers of specimens encountered but not collected. A, YPM HERA 015329 Ichthyophis nigroflavus. B, YPM HERR 019345 Malayopython reticulatus. C, YPM HERR 019346 Tropidolaemus subannulatus. D, YPM HERR 019347 Hebius flavifrons. E, YPM HERR 019348 Eutropis multifasciata. Material. YPM HERR 019347. Photographed approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collector: H.H. Ahmad Sah; preparation type: photographic voucher (Figure 4); 3 July 2012. Comments. A medium-sized water snake of olive brown coloration with a distinct white spot on snout. Commonly found foraging along small forest streams. Endemic to Borneo, it has been considered a denizen of lowland forests up to 700 masl (Stuebing et al. 2014). This record indicates that it may thrive at higher elevations. SQUAMATA: GEKKONIDAE Cyrtodactylus baluensis (Mocquard, 1890) Balu Bow-fingered Gecko Material. YPM HERR 018588. Collected approximately 9 km northwest of the peak of Bukit Pagon: on ground near puddles along the logging road near latrine; collector: K. Zyskowski; 5 July 2012. YPM HERR 018589. Collected approximately 9 km northwest of the peak of Bukit Pagon: stream 61a near main trail; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; 4 July 2012.

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 109 Comments. A tree gecko with irregular dark spots or bands on back. In inhabits hilly, submontane and montane rainforests up to 2,500 masl (Das 2004b). It is endemic to northern Borneo. Cyrtodactylus consobrinus (Peters, 1871) Banded Forest Gecko Material. YPM HERR 018586. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 5 July 2012. Comments. A large forest gecko with distinct white or yellow dorsal bands. Reported to inhabit lowland rainforests up to 110 masl (Das 2004b). The specimen was seen on a large tree trunk approximately 2.5 3.0 m from the ground at night after light rain. SQUAMATA: PYTHONIDAE Malayopython reticulatus (Schneider, 1801) Reticulated Python Material. YPM HERR 019345. Photographed approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: H.H. Ahmad Sah; preparation type: photographic voucher (Figure 4); 5 July 2012. Comments. The largest species of snake in Asia, reaching a maximum total length of 9 10 m (Das 2010; Stuebing et al. 2014). Only approximately half of YPM HERR 019345 was visible, but it we estimate it to have been 1 2 m in total length with a body diameter of 6 7 cm. The species has a distinct reticulated, netlike pattern; a vertical pupil; and rows of pit organs on the upper and lower lips. A common snake of lowland forests including human habitations. The animal encountered near base camp was found active near the trail on a rainy night. SQUAMATA: SCINCIDAE Eutropis multifasciata (Kuhl, 1820) Common Ground Skink Material. YPM HERR 019348. Photographed approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collector: H.H. Ahmad Sah; preparation type: photographic voucher (Figure 4); 5 July 2012. Comments. A medium-sized skink (to 139 mm SVL) characterized by a robust, subcylindrical body; well-developed pentadactyl limbs; and prominently keeled dorsal and flank scales. Primarily terrestrial, although capable of climbing on rocks and tree trunks, they are broad habitat generalists that range from primary forests to highly disturbed agricultural areas and urban park settings. The species was frequently encountered on the trails and logging roads near base camp. Tropidophorus brookei (Gray, 1845) Brooke s Keeled Skink Comments. This small to medium-sized skink (to 101 mm SVL) is diurnal and aquatic (Das 2004b). The scales of the back are keeled, and the dorsal coloration is brown with darker brown spots. Das (2004b) states that the species inhabits lowland dipterocarp forests. We found this species at base camp on logs and rocks near the stream. Adults and juveniles were often seen basking near water but would quickly slip into the water, or under logs or rocks near the water, upon approach. We neither collected nor photographed the species. The species is endemic to Borneo. SQUAMATA: VIPERIDAE Tropidolaemus subannulatus (Gray, 1842) Keeled Pit Viper Material. YPM HERR 018585. Juvenile collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collector: G.J. Watkins-Colwell; 5 July 2012. YPM HERR 019346. Photographed approximately 9 km northwest of the peak of Bukit Pagon: on logging road between icube Base Camp and stream 61a (LP061); collector: H.H. Ahmad Sah; preparation type: photographic voucher (Figure 4); 5 July 2012. Comments. A green viper highly variable in color patterns between males, females and juveniles. Males are mostly green with a row of spots on each side, whereas females and juveniles are also green but have rings of light scales around the body. Males are smaller than females. Scales are distinctly keeled. A pair of heat-sensitive pit organs is located between the nostrils and eyes. A Bornean endemic found in primary and secondary forests (Stuebing et al. 2014). TESTUDINES: TRIONYCHIDAE Dogania subplana (Geoffroy Saint-Hilaire, 1809) Malayan Soft-shelled Turtle Material. YPM HERR 018587. Collected approximately 9 km northwest of the peak of Bukit Pagon: icube Base Camp; collectors: G.J. Watkins-Colwell and H.H. Ahmad Sah; preparation type: 70% alcohol and tissue in RNAlater; 28 June 2012. Comments. A soft-shelled turtle with a flattened, straight-sided shell and a dark median stripe. Known to prefer slow-flowing forest streams in hilly terrain (Lim Boo Liat and Das 1999). Discussion Brunei possesses a staggering richness of biological diversity; however, the spatial distribution of many of these organisms remains little documented. Our survey around Bukit Pagon presents an important step forward in developing a multinational scientific network for future conservation efforts in the region and also provides important baseline data for future survey efforts. Although the period of the survey was brief, we collected 34 species, representing 16 families, including photo vouchers. Many of these specimens are new records for this little-known area,

110 Bulletin of the Peabody Museum of Natural History 57(1) April 2016 FIGURE 5. Satellite images from 2012 (above) and 2013 (below) of the border of Brunei Darussalam and Sarawak. Location of the icube (International Consortium of Universities for the Study of Biodiversity and the Environment) Base Camp is shown. Note the increase in deforested area within Sarawak south and southwest of base camp. GoogleEarth Image 2015 DigitalGlobe.

The Amphibians, Reptiles and Fishes of Brunei Darussalam Ahmad Sah et al. 111 and the retained museum samples have the potential to shed exciting new insights into the evolutionary history of Brunei s species diversity. Conserving Brunei s Biodiversity Like most of the Sundaland biodiversity hot spot, the island of Borneo has seen a massive reduction in primary vegetation over the past several decades (Myers et al. 2000; Curran et al. 2004). As a whole, Sundaland has lost more than 90% of its primary vegetation (Myers et al. 2000), and correspondingly, many parts of Borneo have been deforested or are under intense logging pressure (Brookfield and Byron 1990; Miettinen et al. 2011). Brunei represents a notable exception and has formally protected 17% of its total area as either conservation areas or national parks (Figure 5; Grafe and Das 2014). However, increased urban and agricultural growth threaten to increase levels of sediment runoff and chemical contamination (e.g., pesticides, treated wastewater) in the streams and rivers that transect these forests (Grafe and Das 2014). Given the potential for regional changes or declines in species diversity associated with urbanization and changes in agriculture (Hayes et al. 2006; Shochat et al. 2010; Wotherspoon and Burgin 2011; Seto et al. 2012; Lowry et al. 2013; Konopik et al. 2014b), any documentation of existing patterns of biodiversity represents critical information for future conservation efforts. Over the past two decades, formal scientific surveys of Brunei s amphibians have been limited to only a few areas such as Ulu Temburong National Park, Bukit Teraja Protection Forest or the Tasek Merimbun Heritage Park (Das 1995; Das et al. 2008; Grafe et al. 2010; Ahmadsah 2011; Grafe and Das 2014; Konopik et al. 2014b). Although the expedition occurred over just six days, many endemics were found, with amphibians representing most of the species encountered. Of the amphibian specimens identified to the species level, 44% were endemic to the island of Borneo. While Brunei is not known to possess any amphibians endemic to its borders (Das 2007; Grafe and Das 2014), two-thirds of our sampling days had encounter rates of greater than 40% with Bornean endemic species (Figure 2). This encounter rate is not surprising and supports the argument that Brunei represents an integral component in the conservation of northwestern Borneo s beta diversity (Grafe and Das 2014). However, assessing connectivity among populations of stream-associated amphibians is not trivial, as the distribution of species across the country is heterogeneous and correlated with a host of ecological factors (Keller et al. 2009; Grafe and Das 2014). Further, gaps in our understanding of reptile and fish populations remain a major hurdle in our ability to forecast the potential for continued connectivity or population declines of many additional species native to northwestern Borneo. Although our survey was temporally limited, this effort represents the first step toward documenting the biodiversity of a region under increasing threat from poachers and lumber activities. As such, our data represent an initial baseline to compare with future survey efforts and from which to begin understanding species-level trends in the region. Further, the multi-institutional nature of this survey effort highlights the overwhelming willingness for international scientific cooperation in the effort to document and protect the unique natural resources of the country. Acknowledgments We are grateful to UBD for funding the expedition. We thank the Brunei Forestry Department for cosponsorship and permission to conduct research at Pagon. The Biodiversity Research and Innovation Centre provided export permits. GJWC formally thanks UBD for inviting participation from YPM. We thank Professor Dato Haji Mohamed for serving as the expedition leader, and we are thankful to Dr. Rahayu Sukmaria binti Hj Sukri for organizational support and assistance. Travel for GJWC was funded by YPM. Specimens were exported under permit number 1/2012. HHAS and GJWC would like to acknowledge fond memories of Dr. Timothy Motley, expedition participant and new friend from Old Dominion University, who passed away shortly after the Bukit Pagon expedition. Received 15 December 2015; revised and accepted 18 January 2016. Literature Cited AHMADSAH, H.H. 2011. Anuran species diversity in streams of Bukit Teraja Protection Forest Brunei Darussalam [master s thesis]. Gadong: Universiti Brunei Darussalam.