VENUS 71 (1–2): 49–59, 2013 ©Malacological Society of Japan Land Snail Fauna of Sabah, Borneo, Malaysia Rina Uchida1*, Bakhtiar Effendi Yahya2, Abdul Hamid Ahmad2, Arney Sapaat2 and Kiyonori Tomiyama1 1Earth and Environmental Science, Graduate School of Science and Engineering, Kagoshima University, Korimoto 1-21-35, Kagoshima 890-0065, Japan 2Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, 88400 Kota Kinabalu, Sabah, Malaysia Abstract: We surveyed the land snail fauna of 13 localities including three limestone outcrops in Sabah, Borneo, Malaysia. Land snails were sampled using manual collection and identified to species level where possible. In this study, a total of 39 species was recorded. Species diversity in limestone areas was higher than that in non-calcareous areas. The genus Opisthostoma was found in all the 3 limestone outcrops. A random sample of about 20 shells of this genus from each site contained single but unique taxa among the three limestone outcrops. The three limestone outcrops were isolated by more than 20 km from one another. This result confirmed the high endemicity of this genus. At areas deforested and perturbed by humans, we found two invasive species, Bradybaena similaris (Rang, 1831) and Subulina octona (Bruguière, 1792), which have been widely spread over the world. Keywords: snails, fauna, limestone, Opisthostoma, Sabah, Borneo, Malaysia Introduction Borneo has a rich fauna of terrestrial molluscs (Vermeulen, 1996). The second largest state in Malaysia, Sabah, is located at the northern part of Borneo. About 350 species of land snail have been recorded in Sabah (Thor-Seng Liew, personal communication). Sabah has numerous small limestone outcrops with caves. Limestone mainly consists of calcite, a form of calcium carbonate (CaCO3) (Korsgaard & Redder, 2000). Land snails need calcium carbonate for growth (their shells are made of this material) and reproduction (it is present in their egg shells as well) (Schilthuizen & Vermeulen, 2000). Density of land snails on limestone can be two to 10 times as high as on non-limestone substrates (Schilthuizen et al., 2003). Limestone areas are usually rich in endemic species (Vermeulen, 1996). Certain groups of Bornean land snails, in particular from the family Diplommatinidae, are probably obligate calcicoles, and thus they could only occur on limestone (Schilthuizen et al., 2002). These groups show the highest degree of endemism on limestone hills among Bornean land snails known so far (Schilthuizen & Vermeulen, 2000). Much of the knowledge about the land snails of Sabah is based on samples taken from limestone outcrops. Very little attention has been paid to non-calcareous regions (Schilthuizen et al., 2005). Recent studies have shown that even relatively acidic habitats of low calcium availability and water retention in the soil support some rich malacofauna (Schilthuizen et al., 2006). The malacofauna on limestone outcrops is often similar to that of surrounding non- calcareous areas. Only a few groups of snails, e.g., the diplommatinid genus Opisthostoma, live exclusively on limestone. Limestone tends to occur as small and isolated outcrops. This may have * Corresponding author: [email protected] 50 R. Uchida et al. resulted in high endemicity in these groups diversity in Sabah (Schilthuizen, 2006). This study was conducted as one part of Kagoshima University’s “International training program to protect the diversity of bioresources in tropical areas”. The aim was to examine the land snail fauna in 13 localities in Sabah for conservation of biodiversity in Sabah. Materials and Methods The study sites Our field work was carried out at 13 localities on the east and west sides of Sabah, Borneo, Malaysia: UMS Peak at Universiti Malaysia Sabah; Kiansom Waterfall; Hutan Lipur Kawang; the mangrove forest in Kota Kinabalu Wetland Centre; the parking area of Kota Kinabalu Wetland Centre; the Universiti Malaysia Sabah facility in Sepilok; the Rainforest Discovery Centre in Sepilok; the Gomantong Caves limestone outcrop; an oil palm plantation in Sukau; a limestone outcrop called Hutan Simpan Buntai in Sukau; the Universiti Malaysia Sabah facility in Sukau; the Tabin Wildlife Reserve; and the Madai Caves limestone outcrop (Fig. 1 and Table 1). Sampling protocol Each locality was searched for both empty shells and living snails between October and December, 2010. At each locality 2 to 3 persons carried out random manual collection, paying particular attention to habitats favored by these animals, such as forest floors, tree trunks, the leaves of trees, herbs, dead trees and rock surfaces, over two to three hours. We collected about 20 individual species per locality. Microsnails were preserved in 99% ethanol in the field. After sampling, large snails were Table 1. Locality information. Sampling date No. Location Geographic position* (dd/mm/yyyy) 05/10/2010–06/10/2010, BOR1 UMS Peak at Universiti Malaysia Sabah 06°02´15.0˝N 116°06´57.1˝E 23/10/2010 BOR2 Kiansom Waterfall 05°58´25.4˝N 116°12´23.8˝E 02/11/2010 BOR3 Hutan Lipur Kawang 05°45´39.0˝N 116°02´24.7˝E 11/11/2010 the mangrove forest in Kota Kinabalu Wetland BOR4 05°59´06.3˝N 116°05´19.1˝E 22/10/2010 Centre BOR5 the parking area of Kota Kinabalu Wetland Centre 05°59´15.7˝N 116°05´21.4˝E 22/10/2010 26/10/2010–27/10/2010, BOR6 the Universiti Malaysia Sabah facility in Sepilok 05°30´32.7˝N 118°17´12.4˝E 29/10/2010 BOR7 the Rainforest Discovery Centre in Sepilok 05°52´30.8˝N 117°56´42.0˝E 27/10/2010–28/10/2010 BOR8 the Gomantong Caves limestone outcrop 05°31´52.1˝N 118°04´20.7˝E 06/11/2010–07/11/2010 BOR9 an oil palm plantation in Sukau 05°31´33.4˝N 118°13´18.8˝E 17/10/2010 a limestone outcrop called Hutan Simpan Buntai in BOR10 05°31´30.6˝N 118°13´17.5˝E 17/10/2010 –18/10/2010 Sukau BOR11 the Universiti Malaysia Sabah facility in Sukau 05°52´29.3˝N 117°56´48.2˝E 16/10/2010, 18/10/2010 BOR12 the Tabin Wildlife Reserve 05°11´40.8˝N 118°30´07.7˝E 14/10/2010–15/10/2010 BOR13 the Madai Caves limestone outcrop 04°42´53.5˝N 118°09´20.4˝E 15/11/2010–16/11/2010 * Geographic positions were mapped by using GPS. Each locality corresponds to that in Fig. 1B. Land Snail Fauna of Sabah, Borneo 51 Fig. 1. Map of Sabah, with locations of the sampling sites. A. Sabah state is located at the northern part of Borneo, Malaysia. B. Black squares (■ ) indicate 13 localities searched in this study; BOR1, UMS Peak at Universiti Malaysia Sabah; BOR2, Kiansom Waterfall; BOR3, Hutan Lipur Kawang; BOR4, the mangrove forest in Kota Kinabalu Wetland Centre; BOR5, the parking area of Kota Kinabalu Wetland Centre; BOR6, the Universiti Malaysia Sabah facility in Sepilok; BOR7, the Rainforest Discovery Centre in Sepilok; BOR8, the Gomantong Caves limestone outcrop; BOR9, an oil palm plantation in Sukau; BOR10, a limestone outcrop called Hutan Simpan Buntai in Sukau; BOR11, the Universiti Malaysia Sabah facility in Sukau; BOR12, the Tabin Wildlife Reserve; BOR13, the Madai Caves limestone outcrop. boiled, and then their soft bodies were removed. Identifications Identification based on shell characteristics followed the “Borneensis” mollusc collection at the Institutefor Tropical Biology and Conservation, Universiti Malaysia Sabah (Vermeulen, 52 R. Uchida et al. Schilthuizen & Liew, in preparation). We deposited all the specimens in the Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah. Results In total, we collected the following 39 species (Table 2). Class Gastropoda Clade Architaenioglossa Family Cyclophoridae Gray, 1847 1. Alycaeus jagori Martens, 1859 (Fig. 3) 2. Chamalycaeus specus (Godwin-Austen, 1889) (Fig. 4) [Many individuals were found in the Gomantong Caves.] 3. Cyclophorus kinabaluensis E. A. Smith, 1895 (Fig. 5) [Only empty shells were found.] 4. Cyclophorus semisulcatus (Sowerby II, 1843) (Fig. 6) [Only empty shells were found.] 5. Japonia jucunda (E. A. Smith, 1893) (Fig. 7) 6. Japonia sp. (Fig. 8) 7. Leptopoma pellucidum (Grateloup, 1840) (Fig. 9) [This species was found on tree leaves.] 8. Leptopoma sericatum (Pfeiffer, 1851) (Fig. 10) [This species was found on tree leaves.] 9. Leptopoma undatum (Metcalfe, 1852) (Fig. 11) [This species was found on tree leaves.] 10. Opistoporus iris (Godwin-Austen, 1889) (Fig. 12) [This species was found on the forest floor.] 11. Pterocyclos tenuiiabiatus (Metcalfe, 1851) (Fig. 13) [This species was found on the forest floor.] Family Diplommatinidae Pfeiffer, 1856 12. Diplommatina gomantongensis E. A. Smith, 1894 (Fig. 14) [This species was found on the surface of the Gomantong Caves limestone outcrop and the Madai Caves limestone and litter layer nearby.] 13. Diplommatina rubicunda (Martens, 1864) (Fig. 15) 14. Opisthostoma concinnum Fulton, 1901 (Figs. 2A–C; 16) [This species was found on the surface of limestone outcrops called Hutan Simpan Buntai in Sukau.] 15. Opisthostoma mirabile E. A. Smith, 1893 (Figs. 2D–F; 17) [This species was found on the surface of limestone outcrops of Gomantong Caves.] 16. Opisthostoma lissopleuron lissopleuron Vermeulen, 1994 (Figs. 2G–I; 18) [This species was found on the surface of the Madai Caves limestone outcrop.] Clade Neritimorpha Family Helicinidae Férussac, 1822 17. Sulfurina martensi (Issel, 1874) (Fig. 19) [This species was found on tree leaves.] Family Hydrocenidae Troschel, 1857 18. Georissa sp. (Fig. 20) [This species was found on the surface of the Madai Caves limestone outcrop, and inhabited the same place as Opisthostoma lissopleuron lissopleuron.] 19. Bor-01 (Fig. 21) [This species was found on the surface of the Madai Caves limestone outcrop.] Clade Pulmonata Family Achatinidae Swainson, 1840 20. Achatina fulica Bowdich, 1822 (Fig. 22) Family Ariophantidae Godwin-Austen, 1888 Land Snail Fauna of Sabah, Borneo 53 Table 2.