Schistura kottelati, a new species of loach from the Phong Nha-Kẻ Bàng National Park in central Vietnam (Teleostei: Nemacheilidae)

Size: px

Start display at page:

Download "Schistura kottelati, a new species of loach from the Phong Nha-Kẻ Bàng National Park in central Vietnam (Teleostei: Nemacheilidae)"

Estella Webster
6 years ago
Views:

1 Tuan et al.: Schistura kottelati RAFFLES BULLETIN OF ZOOLOGY 66: Date of publication: 8 March Taxonomy & Systematics Schistura kottelati, a new species of loach from the Phong Nha-Kẻ Bàng National Park in central Vietnam (Teleostei: Nemacheilidae) Ho Anh Tuan 1*, Hoang Ngoc Thao 2 & Ngo Xuan Quang 3 Abstract. Schistura kottelati, new species, is described from the Hung Dang Valley (Phong Nha-Kẻ Bàng National Park) in central Vietnam. It is distinguished from all other species of Schistura known from Vietnam and adjacent areas in Laos by a unique combination of characters, including features of lateral line and body pigmentation, counts of fin rays, and barbel and body measurements. Key words. cypriniformes, taxonomy, morphology, Southeast Asia, karstic area 1 Department of Zoology, Vinh University, 182 Le Duan Street, Vinh City, Vietnam; hoanhtuan18@gmail.com 2 Department of Zoology, Hong Duc University, 565 Quang Trung Street, Thanh Hoa City, Vietnam INTRODUCTION The Nemacheilid loach genus Schistura McClelland, 1838 is one of the most characteristic and widespread elements in the freshwater fauna of Southeast Asia. Worldwide, Kottelat (2012) included 193 species in this genus, and each year new species continue to be described (e.g., Kottelat, 2017a f). Twenty-nine species have been reported from Vietnam (Kottelat, 2012; Freyhof & Serov, 2001; Kottelat, 2000, 2001a, b; Kottelat & Leisher, 2012; Nguyen & Nguyen, 2007). Two species are known from the Gianh River drainage: S. hingi and S. pervagata (Kottelat, 1998, 2012; Freyhof & Serov, 2001). The Phong Nha-Kẻ Bàng National Park is located in the middle of the Annamite Mountain Range in the Quang Binh province, and shares its boundary with the Hin Namno Nature Reserve in the Lao PDR to the west. Surface water is drained via the Gianh River basin eastwards to the South Chinese Sea. The park is located in one of the most outstanding limestone karst ecosystems in the world, covering more than 104 km of caves and underground rivers and is inscribed on the World Heritage List since 2003 (UNESCO, 2016). It is one of the largest and oldest karst areas in Asia (UNESCO, 2016). Recent collections in Hung Dang valley in Phong Nha- Kẻ Bàng National Park resulted in a species of Schistura that could not be assigned to any described species and is described in the present study. 3 Institute of Tropical Biology, Vietnam Academy of Science and Technology. 85 Tran Quoc Toan, Ho Chi Minh city, Vietnam National University of Singapore ISSN (electronic) ISSN (print) MATERIALS AND METHODS After anaesthesia, fishes were fixed either in 10% formaldehyde and later transferred into 4% formaldehyde for storage or fixed and stored in 90% ethanol. All measurements and counts follow Kottelat (1990). Measurements were made point-to-point with digital callipers to the nearest 0.1 mm. Abbreviations: BMVU, Biological Museum Vinh University, Vinh, Vietnam; CMK, Collection Maurice Kottelat, Cornoll, Switzerland; ZRC, Lee Kong Chian Natural History Museum, National University of Singapore, Singapore; SL, standard length; HL, dorsal head length. Schistura kottelati, new species (Figs. 1 5, Table 1) Holotype. BMVU 1101, 37.0 mm SL; Vietnam: Quang Binh province: Bo Trach district: Xuan Trach commune: a pool in Hung Dang valley of Phong Nha-Kẻ Bàng National Park; N, E, 83 m asl, Ho Anh Tuan & Hoang Ngoc Thao, 24 August Paratypes. BMVU , 27, mm SL; ZRC (formerly BMVU ), 9, mm SL; same data as holotype. Diagnosis. Schistura kottelati differs from the other species of genus Schistura known from Vietnam and adjacent areas in Laos by the unique combination of the following characters: lateral line very short, with 5 14 pores; pelvic fin with 1 unbranched and 8 branched rays; a long maxillary barbel (reaching vertical through nape) and inner rostral barbel (reaching vertical through anterior margin of eye); body without obvious markings; caudal fin deeply forked (length of median ray times in length of upper slobe); no external sexual dimorphism; caudal peduncle slender (its length % SL); a large eye (eye diameter % SL); and wide interorbital region (interorbital width % SL). 142

2 RAFFLES BULLETIN OF ZOOLOGY 2018 Description. See Figs. 1 5 for general appearance and Table 1 for morphometric data of holotype and 27 paratypes. A small-sized, moderately elongated loach. Body anteriorly slightly compressed, caudal peduncle compressed. Maximum body depth between pectoral-fin base and dorsal-fin origin. Head depressed, depth at nape (mean 0.9) times in its width. Snout round in lateral view, slightly squarish in dorsal view. Width of head increasing from level of mouth backwards to anterior part of opercle, from that point onwards body regularly narrowing until caudal-fin origin. Caudal fin deeply forked. Low ventral and dorsal adipose crests on caudal peduncle; caudal peduncle (mean 1.4) times longer than deep. Distal margin of dorsal fin convex. Largest known individual 42.1 mm SL. Dorsal fin with 3 simple and 7½ branched rays; distal margin of dorsal fin straight or very slightly convex. Anus slightly in front of anal-fin origin. Anal fin with 3 simple and 5½ branched rays, reaching about halfway to caudal fin base. Caudal fin with 9+8 branched rays (9+9 in one paratype), lobes rounded or slightly pointed. Pelvic fin with 1 unbranched and 8 branched rays; origin under last unbranched or first branched dorsal-fin ray; reaching distinctly beyond half of distance to anal-fin origin; usually just reaching anus. Pectoral fin with 1 unbranched and 9 branched rays, reaching half of distance between bases of pectoral and pelvic fins. Posterior part of body covered by embedded scales. Scales only sparsely-set at predorsal flank, deeply embedded. Lateral line incomplete, with 5 14 pores (mean 10), reaching maximally to pelvic-fin base. Cephalic lateral line system with 6 supraorbital, 6+8 infraorbital, 8 10 preoperculomandibular and 3 supratemporal pores. Anterior nostril pierced in front side of a flap like tube, with a low anterior rim. Eye times in head length, directed dorsolaterally, diameter (mean 1.8) times in interorbital width. Interorbital distance increasing with body size, while relative size of eye slightly decreasing. Processus dentiformis wide, low, broadly rounded. Mouth gape about times wider than long (Fig. 5a). Lips thin; upper lip with a well-marked median incision and no furrows. Lower lip with a narrow median interruption, no furrows, but few small folds towards corners of mouth. Inner rostral barbel reaching vertical of anterior margin of eye; outer one reaching vertical of posterior margin of eye. Maxillary barbel reaching vertical of nape. Colouration. In freshly preserved specimens, body sides brownish, darker colour on dorsal side and lighter on belly; becoming white after a few days in formalin. Dorsal midline covered by thick yellow stripe from posterior of head, via dorsal-fin base, to caudal-fin base. Head a faint purplish colour laterally without any obvious pigmentation or patterns. Caudal base with a thin and faint dark bar, thicker at upper and lower extremities, very weak in middle area and not reaching dorsal and ventral midlines. Fins hyaline, without pigments on rays and membranes. Overall colouration of juveniles as adult individuals but having a series of 3 7 dark blotches on flanks, varying in shape. In some juveniles, a chain of tiny black dots along lateral line and dorsal midline (Fig. 3). Sexual dimorphism. None observed. Distribution and habitat. Schistura kottelati is presently known only from a single pool (Fig. 6) in a large karstic area of the Hung Dang valley, Quang Binh province (Fig. 7). Hung Dang valley is located in the core area of the Phong Nha-Kẻ Bàng National Park. The pool where the species was found is about 2 3 meters large and 0.7 meters at its deepest point. Although located in the Gianh River drainage, the pool is about 83 m asl and completely isolated from any adjacent water bodies. Water is available by rain and underground water. This pool is isolated and the nearest water body is 5 km away. It is a very important site protected by the National Park management because it is also a source of water for the local community. No other fish species were observed in the pool. We do not expect the species to be endemic to this very small pool, but suspect, that the major population lives underground. Etymology. The species is named for Maurice Kottelat, in appreciation for his research on Eurasian freshwater fishes, among others those of Vietnam. A noun in genitive. Remarks. Schistura kottelati is known only a single locality in Central Vietnam. In the latest and most comprehensive survey of the nemacheilid fauna of Central Vietnam, Freyhof & Serov (2001) reported 19 species of Schistura from Central Vietnam (S. antennata, S. bachmaensis, S. carbonaria, S. dalatensis, S. finis, S. hingi, S. huongensis, S. implicata, S. konphengi, S. kontumensis, S. namboensis, S. nasifilis, S. pervagata, S. psittacula, S. sokolovi, S. spiloptera, S. susannae, S. thanho, and S. yersini). Schistura kottelati differs from all these species by not having any distinct dark pigmentation pattern on the body, while the other species have vertical bars on the body sides (sometimes weak, but present at least in the form of dorsal saddles or large midlateral blotches) and a distinct black bar at the base of caudal fin. It has a shorter lateral line than any other Central Vietnamese species (5 14 pores vs. at least 38). According to Kottelat (2001a), in northern Vietnam another six species of Schistura are known or expected to occur: Schistura callichromus, S. caudofurca, S. chapaensis, S. fasciolata, S. incerta, and S. orthocauda. Schistura kottelati differs from all these species by lacking a colour pattern (vs. having head and body covered with large black blotches in S. callichromus or having distinct dark bars on the body in the other species) and having a very long rostral barbel (inner rostral barbel reaching vertical through anterior margin of eye vs. not reaching vertical through anterior margin of eye). Additional species of Schistura that have been described from northern Vietnam since the publication by Kottelat (2001a, 2012) are: S. athos, S. hoai, S. mobbsi, S. phongtoensis, S. pumatensis, S. sonlaensis, S. spekuli, S. tamduongensis, and S. trilineata. Schistura kottelati differs from all these species except S. mobbsi and S. spekuli by 143

Tuan et al.: Schistura kottelati Fig. 1.

0 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig.

5 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig.

8 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig.

3 Tuan et al.: Schistura kottelati Fig. 1. Schistura kottelati BMVU 1101, holotype, 37.0 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig. 2. Schistura kottelati, BMVU 1104, paratype 36.5 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig. 3. Schistura kottelati, BMVU 1107, paratype 33.8 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. Fig. 4. Schistura kottelati, BMVU 1107, paratype 33.8 mm SL; Vietnam: Phong Nha-Kẻ Bàng National Park. 144

4 RAFFLES BULLETIN OF ZOOLOGY 2018 Table 1. Morphometric and meristic data of Schistura kottelati. Values of holotype included in range, mean and Standard deviation (SD). Holotype Paratypes (n = 27) SL (mm) 37.0 Mean Range SD In percent of SL Total length Dorsal head length Lateral head length Predorsal length Pre-pelvic length Pre-anus length Preanal length Head depth (at eye) Head depth (at nape) Body depth Depth of caudal peduncle Length of caudal peduncle Snout length Head width (at nares) Maximum head width Body width (dorsal origin) Body width (anal origin) Eye diameter Interorbital width Height of dorsal fin Length of upper caudal lobe Length of lower caudal lobe Length of median caudal rays Depth of anal fin Length of pelvic fin Length of pectoral fin Maxillary barbel length In percent of dorsal head length Lateral head length Head depth (at eye) Head depth (at nape) Snout length Head width (at nares) Maximum head width Eye diameter Interorbital width Length of pectoral fin Maxillary barbel length lacking a colour pattern or pigmentation in adults (vs. having a middorsal and a midlateral stripe in S. sonlaensis and S. trilineata or bars on the body in the other species) and by having longer barbels (inner rostral barbel reaching vertical through anterior margin of eye vs. not reaching vertical through anterior margin of eye). Schistura kottelati differs from S. mobbsi and S. spekuli by the presence of eyes (vs. absence) and 9 rays in the pelvic fin (vs. 7 in S. mobbsi, 8 in S. spekuli). The area in Laos adjacent to the Gianh River drainage is drained by the Xe Bangfai, a left tributary of the Mekong that has been studied by Kottelat (1998, 2000, 2001b). The following species of Schistura have been recorded in this drainage: S. daubentoni, S. isostigma, S. nicholsi, and S. punctifasciata. In the middle of its course, the Xe Bangfai flows for several km underground in a natural tunnel. Upstream of the tunnel, the Xe Bangfai flows parallel and close to the Lao-Vietnam border. Until now, a single species of Schistura (S. nicholsi) has been collected upstream of the tunnel (Kottelat, 1998, 2016, and pers. comm.) but this area is still very poorly known and difficult to access. Schistura kottelati differs from S. nicholsi by the absence (vs. presence) of dark bars on the body sides, by having longer barbels 145

Tuan et al.: Schistura kottelati A Fig. 5. Head of Schistura kottelati. C BMVU 1112, 31.0 mm SL, ventral view; B, BMVU 1125, 30.6 mm SL, lateral view. (maxillary barbel reaching, vs.

complete) and a deeply forked caudal fin (length of median ray 1.5 1.7 times in length of upper lobe vs. 1.1 1.3). Comparative material. Schistura antennata: IAPG A3392 3400, 9, 25.9 48.

Schistura bachmaensis: IAPG A10952 10596, 5, 35.8 42.7 mm SL; Vietnam: Thua Thien Hue prov.: stream Suoi Voi; 16 14.58 N 107 59.39 E. Fig. 6.

5 Tuan et al.: Schistura kottelati A Fig. 5. Head of Schistura kottelati. C BMVU 1112, 31.0 mm SL, ventral view; B, BMVU 1125, 30.6 mm SL, lateral view. (maxillary barbel reaching, vs. not reaching, vertical through nape), a shorter lateral line (lateral line with 8 14 pores, not reaching vertical through pelvic-fin origin vs. complete) and a deeply forked caudal fin (length of median ray times in length of upper lobe vs ). Comparative material. Schistura antennata: IAPG A , 9, mm SL; Vietnam: Ha Tinh prov.: stream at Son Kim; N E. Schistura athos: RIA1 uncatalogised, 2, mm SL; Vietnam: Dien Bien prov.: Creek Nâm Ngam. Schistura bachmaensis: IAPG A , 5, mm SL; Vietnam: Thua Thien Hue prov.: stream Suoi Voi; N E. Fig. 6. Type locality of Schistura kottelati; Vietnam: Phong Nha-Kẻ Bàng National Park, pond in Hung Dang valley, 24 August Schistura carbonaria: IAPG A , 5, mm SL; Vietnam: Thua Thien Hue prov.: stream Khe Vinh An; N E. Schistura kontumensis: IAPG A , 3, mm SL; Vietnam: Kontum prov.: stream Pako; N E. Schistura caudofurca: RIA1 uncatalogued, 2, mm SL; Vietnam: Ha giang prov.: Lo River. Schistura namboensis: ZFMK , 10 paratypes, mm SL; Vietnam: Dac Lac prov.: small stream at Ea Nuol. IAPG A , 14, mm SL; Vietnam: Gia Lei prov.: stream Azun; N E. Schistura dalatensis: IAPG A , 12, mm SL; Vietnam: Lam Dong prov.: stream Dai Tan; N E. Schistura hingi: IAPG A , 12, mm SL; Vietnam: Ha Tinh prov.: small tributary of river Lam; N E. Schistura nicholsi: CMK 24709, 3, mm SL; Laos: Bolikhamsai prov.: river Nam Xao. IAPG A9602, 1, 40.1 mm SL; Thailand: Phetchabun prov.: Mun River; N E. Schistura huongensis: IAPG A , 7, mm SL; Vietnam: Thua Thien Hue prov.: stream Khe Vinh An; N E. Schistura implicata: CMK 25835, 3, mm SL; Laos: Houapan prov.: River Nam Xam; N E. Schistura pervagata: CMK 25708, 3, mm SL; Laos: Houapan prov.: River Ma. CMK257751, 3, mm SL; Laos: Houapan prov.: River Ma; N ʹ44ʺE. Schistura konphengi: IAPG A , 6, mm SL; Vietnam: Thua Thien Hue prov.: stream running to Sesap; N E. Schistura phongthoensis: RIA1 uncatalogued, 5, mm SL; Vietnam: Lai Chau prov.: Nam So River (type locality). 146

6 RAFFLES BULLETIN OF ZOOLOGY 2018 Fig. 7. Type locality of Schistura kottelati (black circle) in Phong Nha-Kẻ Bàng National Park, central Vietnam. Schistura psittacula: IAPG A3200v3205, 6, mm SL; Vietnam: Quang Tri prov.: stream Cam Lo; N E. Schistura sokolovi: IAPG A , 2, mm SL; Vietnam: Gia Lei prov.: stream Azun; N E. Schistura spiloptera: IAPG A , 17, mm SL; Vietnam: Thua Thien-Hue: unnamed mountain stream; N E. Schistura susannae: IAPG A , 10, mm SL; Vietnam: Quang Nam Danang prov.: stream Mong Mo; N E. Schistura thanho: IAPG A , 10, mm SL; Vietnam: Binh Dinh prov.: stream Vinh Thanh; N E. Schistura yersini: IAPG A , 12, mm SL; Vietnam: Lam Dong prov.: stream Dai Tan; N, E. Further data obtained from Endruweit (2013), Freyhof & Serov (2001), Kottelat (1998, 2000, 2001a, b, 2016), Nguyen et al. (2010), and Zhu (1989). ACKNOWLEDGEMENTS The first author would like to thank the Nature Conservation and Sustainable Natural Resource Management in Phong Nha-Kẻ Bàng National Park Region Project, Vietnam, KfW component for their financial support. We are also grateful to the Director Board and Scientific Research Center in the Phong Nha-Kẻ Bàng National Park for their assistance during field work, especially L. Thuc Dinh for traveling with the authors to the Hung Dang valley. A. Crivoi and S. Nguyen Si are also acknowledged for help with specimen preservation. Finally, we thank J. Bohlen and M. Kottelat for help with comparative material and suggestions on an earlier version of the manuscript, and two reviewers for their comments and suggestions. LITERATURE CITED Endruweit M (2013) Taxonomical notes on selected freshwater fish species described from northern and central Vietnam (Cypriniformes: Balitoridae, Cobitidae, Cyprinidae, Nemacheilidae; Perciformes: Channidae, Osphronemidae; Synbranchiformes: Mastacembelidae). Zoological Research, 35: Freyhof J & Serov DV (2001) Nemacheiline loaches from Central Vietnam with description of a new genus and 14 new species (Cypriniformes: Balitoridae). Ichthyological Exploration of Freshwaters, 12:

7 Tuan et al.: Schistura kottelati Kottelat M (1990) Indochinese Nemacheilines. A Revision of Nemacheiline Loaches (Pisces: Cypriniformes) of Thailand, Burma, Laos, Cambodia and Southern Viet Nam. Pfeil, München, 262 pp. Kottelat M (1998) Fishes of the Nam Theun and Xe Bangfai basins, Laos, with diagnoses of twenty two new species (Teleostei: Cyprinidae, Balitoridae, Cobitidae, Coiidae and Odontobutidae). Ichthyological Exploration of Freshwaters, 9: Kottelat M (2000) Diagnoses of a new genus and 64 new species of fishes from Laos (Teleostei: Cyprinidae, Balitoridae, Bagridae, Syngnathidae, Chaudhuriidae and Tetraodontidae). Journal of South Asian Natural History, 5: Kottelat M (2001a) Freshwater Fishes of Northern Vietnam. A Preliminary Check List of the Fishes Known or Expected to Occur in Northern Vietnam with Comments on Systematics and Nomenclature. World Bank, Washington, iii pp., 15 pls. Kottelat M (2001b) Fishes of Laos. WHT Publications, Colombo, 198 pp. Kottelat M (2012) Conspectus Cobitidum: An inventory of the loaches of the world (Teleostei: Cypriniformes: Cobitoidei). Raffles Bulletin of Zoology, Supplement, 26: Kottelat M (2016) The fishes of the Nam Theun and Xe Bangfai drainages, Laos. Hydroécologie Appliquée, 19: Kottelat M (2017a) Schistura indawgyiana, a new loach from Lake Indawgyi basin, Myanmar (Teleostei: Nemacheilidae). Ichthyological Exploration of Freshwaters, 28: 1 8. Kottelat M (2017b) Schistura systomos, a new species of loach from southern Laos (Teleostei: Nemacheilidae). Ichthyological Exploration of Freshwaters, 28: Kottelat M (2017c) Schistura titan, a new species of loach from Dakchung Plateau, southern Laos (Teleostei: Nemacheilidae). Ichthyological Exploration of Freshwaters, 28: Kottelat M (2017d) Schistura colossa and S. klydonion, two new species of loaches from Bolaven Plateau, southern Laos (Teleostei: Nemacheilidae). Raffles Bulletin of Zoology, 65: Kottelat M (2017e) Schistura thavonei, a new species of loach from northwestern Laos (Teleostei: Nemacheilidae). Raffles Bulletin of Zoology, 65: Kottelat M (2017f) Three new species of loaches of the genus Schistura from the Nam Ngiep drainage, central Laos (Teleostei: Nemacheilidae). Raffles Bulletin of Zoology, 65: Kottelat M & Leisher C (2012) Fishes from Phuong Hoang cave, northern Vietnam, with description of a new species of loach (Teleostei: Nemacheilidae). Ichthyological Exploration of Freshwaters, 23: McClelland J (1838) Observations on six new species of Cyprinidae, with an outline of a new classification of the family. Journal of the Asiatic Society of Bengal, 7: Nguyen XK & Nguyen HD (2007) A new species of genus Schistura from Pu Mat National Park, Nghe An province, Vietnam. Journal of Biology, 29(2): [In Vietnamese, with English summary] Nguyen TH, Nguyen VH & Hoang TT (2010) Two new species of Oreias Sauvage, 1874 discovered in Son La city, Vietnam. Journal of Biology, 32(4): [In Vietnamese, with English summary] UNESCO (2016) Phong Nha-Kẻ Bàng National Park. unesco.org/en/list/951. (Accessed 23 April 2015). Zhu SQ (1989) The loaches of the subfamily Nemacheilinae in China. Jiangsu, Nanjing, 150 pp. [In Chinese] 148

A new genus and two new species of loaches (Teleostei: Nemacheilidae) from Myanmar

1 Ichthyol. Explor. Freshwaters, Vol. 22, No. 1, pp. 1-10, 7 figs., 2 tabs., March 2011 2011 by Verlag Dr. Friedrich Pfeil, München, Germany ISSN 0936-9902 A new genus and two new species of loaches (Teleostei: