THE RAFFLES BULLETIN OF ZOOLOGY 2011 THE RAFFLES BULLETIN OF ZOOLOGY 2011 59(2): 195–199 Date of Publication: 31 Aug.2011 © National University of Singapore CROSSOCHEILUS ELEGANS, A NEW SPECIES OF FISH FROM NORTHERN BORNEO (TELEOSTEI: CYPRINIDAE) Maurice Kottelat Route de la Baroche 12, Case Postale 57, 2952 Cornol, Switzerland (address for correspondence). E-mail: [email protected] Tan Heok Hui Department of Biological Sciences, National University of Singapore, Lower Kent Ridge Road, Singapore 119260, Republic of Singapore. E-mail: [email protected] (corresponding author) ABSTRACT. – Crossocheilus elegans, new species, is described from the Kinabatangan and Segama drainages in Sabah, northern Borneo. It is distinguished from all other species of the genus by its colour pattern consisting of a blackish midlateral stripe extending from the tip of the gill opening to the middle of the base of the caudal fi n, separated from the dark brown dorsum by a pale yellowish-brown stripe. KEY WORDS. – Cyprinidae, Malaysia, new species. INTRODUCTION Crossocheilus elegans, new species (Fig. 1) Crossocheilus species are small benthic fi shes of the family Cyprinidae found throughout the Sundaic and Indochinese Epalzeorhynchus kalliurus (non Smith, 1945): Inger & Chin, regions. Some species are also recorded from southern 1962: 99. Asia (e.g., C. latius, C. periyarensis), but their real generic Crossocheilus cobitis (non Bleeker, 1853): Martin-Smith & Tan, 1998: 580. affi nities are not certain. They inhabit a variety of habitats from large rivers to head waters, but they are generally Holotype. – ZRC 51184, 78.2 mm SL; Borneo: Sabah: Danum associated with substrates consisting of large stones or rocks, Valley, Kinabatangan drainage, stream at km 111 on main line and fast-fl owing water. One species (C. cobitis) is frequently west after turnoff to Borneo Rainforest Lodge (5°01'06.0"N found under logs, including fl oating houses and boats. Most 117°32'38.4"E); H. H. Tan et al., 3 Oct.1996. of the named Sundaic species have been discussed by Tan & Kottelat (2009). We describe here a species from northern Paratypes. – ZRC 40420, 1, 85.4 mm SL; same data as holotype. Borneo, which had been misidentifi ed as Epalzeorhynchos – ZRC 44002, 3, 35.3–106.3 mm SL; Borneo: Sabah: Danum kalliurus for about 40 years. Valley, Kinabatangan drainage, stream at km 113 on main line west (logging road) after turnoff to Borneo Rainforest Lodge (5°00'37.6"N 117°31'43.88"E); H. H. Tan et al., 3 Oct.1996. – ZRC 40395, 3, 74.1–96.8 mm SL; Borneo: Sabah: Danum Valley, Kinabatangan MATERIAL AND METHODS drainage, Sungai Malua at ca. km 95 on main line west after turnoff to Borneo Rainforest Lodge (5°05'43.5"N 117°37'33.2"E); H. H. See Tan & Kottelat (2009) for comparison material, Tan et al., 3 Oct.1996. – CMK 20121 (ex-ZRC 43974), 3, 77.0–83.6 diagnoses and key to most Sundaic species of Crossocheilus. mm SL; Borneo: Sabah: Danum Valley, Sungai Segama, in front Material examined is deposited in the Zoological Reference of Danum Valley Field Centre (4°57'42.5"N 117°48'21.6"E); H. Collection, Raffles Museum of Biodiversity Research, H. Tan et al., 1 Oct.1996. National University of Singapore (ZRC) and the collection of the fi rst author (CMK). Specimens were measured from Diagnosis. – Crossocheilus elegans is immediately the left side using dial callipers (up to 0.5 mm). Methods for distinguished from all other species of the genus by its colour measurements and counts follow Kottelat (2001). Vertebrae pattern consisting of a blackish midlateral stripe extending counts follow Roberts (1989). from the tip of the gill opening to the middle of the base of the caudal fi n, separate from the dark brown dorsum by a pale yellowish brown stripe. In all other named Crossocheilus with a black midlateral stripe, the dorsum is olive brown, 195 Kottelat & Tan: A new species of Crossocheilus from Northern Borneo much paler than the midlateral stripe, and there is no yellow transverse line on caudal peduncle, 3 or 3½ scales between stripe between the dorsum and the black stripe. lateral line and pelvic-fi n origin. Description. – General appearance in Fig. 1; morphometric Rostral barbel about equal to eye diameter, maxillary barbel data of holotype and 4 paratypes in Table 1. Dorsal fi n with 3 about 2/ of eye diameter. Upper lip with 12–17 fi mbriae, 3 simple and 8½ branched rays; origin above lateral line scale entirely covered by small papillae. Anterior edge of lower 9. Pectoral fi n slightly falcate, with 14 rays, reaching ¾ of lip with a few large papillae. distance to pelvic-fi n base. Pelvic fi n triangular to slightly falcate, with 9 rays, reaching about 2/ of distance to anal-fi n Coloration. – Upper surface of head grayish brown, lower 3 origin and slightly beyond anus; axillary scale present. Anus surface yellow. Body background pale yellowish brown. separated from anal-fi n origin by 3–4 scales. Anal with 2 A conspicuous blackish brown midlateral stripe about 2 simple and 5½ branched rays. Caudal fi n with 10+9 principal scales wide, from upper extremity of gill opening to base rays, 9+8 branched. Caudal peduncle depth 1.49–1.65 times in of caudal fi n, extending onto proximal-most part of median length. 31–32 + 2–3 scales along lateral line, 8–10 predorsal caudal-fi n rays. Midlateral stripe margined above by a pale scales, ½4/1/5½ scales in transverse line, ½3/1/3½ scales in yellowish-brown stripe about 1 to 1.5 scale wide, sometimes Fig. 1. Crossocheilus elegans, holotype, ZRC 51184, 78.2 mm SL (dorsal, lateral and ventral views); Sabah: Danum Valley, Kinabatangan drainage. 196 THE RAFFLES BULLETIN OF ZOOLOGY 2011 Table 1. Meristic and morphometric data of holotype (H) and 4 paratypes of Crossocheilus elegans. ZRC 51184 (H) ZRC 40420 ZRC 44002 ZRC 40395 Standard length (mm) 78.2 85.4 106.3 96.8 82.7 Percentage of standard length Head length 21.1 22.7 22.1 22.7 22.2 Total length 139.9 139.3 135.1 134.3 137.5 Predorsal length 45.8 46.8 47.0 45.1 45.1 Preanal length 73.5 73.4 73.8 71.9 71.1 Prepelvic length 47.1 46.7 48.0 48.3 47.6 Body depth at dorsal-fi n origin 24.7 25.1 25.7 22.9 23.7 Body depth at anus 16.6 16.9 17.6 17.4 16.8 Depth of caudal peduncle 11.8 12.2 11.7 12.0 11.6 Length of caudal peduncle 17.6 20.1 19.2 18.1 18.0 Length of dorsal-fi n base 17.6 18.5 17.1 18.3 18.0 Length of anal-fi n base 10.1 9.0 8.8 10.1 9.9 Length of pelvic fi n 23.1 24.4 21.1 20.2 24.1 Length of pectoral fi n 24.8 25.2 23.0 21.7 24.5 Length of upper caudal-fi n lobe 40.2 36.9 35.7 34.6 38.7 Length of lower caudal-fi n lobe 38.2 36.1 34.2 32.5 35.6 Head depth 13.8 14.1 14.0 14.7 14.6 Head width 13.8 14.1 14.5 13.7 14.0 Snout length 9.1 10.7 10.3 10.3 10.6 Orbit diameter 5.1 4.6 4.6 4.3 5.1 Interorbital width 9.2 10.2 9.6 9.4 10.0 Percentage of head length Head depth 65.5 61.9 63.4 64.5 65.8 Head width 65.5 61.9 65.5 60.5 63.0 Snout length 43.0 46.9 46.8 45.5 47.8 Orbit diameter 24.2 20.1 20.9 19.1 22.8 Interorbital width 43.6 44.8 43.4 41.4 45.1 Ratio length/depth of caudal peduncle 1.49 1.65 1.64 1.51 1.55 continued on head by a pale area behind eye. Dorsum dark Etymology. – From the Latin elegans, meaning elegant. An brown, with darker scale margins and scale pockets forming adjective. a reticulate pattern, sometimes forming a narrow darker line along yellowish stripe below. Scales on rows 1–2 under Remarks. – Crossocheilus elegans has fi rst been recorded by midlateral stripe with dark brown pockets, sometimes forming Inger & Chin (1962: 99) who identifi ed it as Epalzeorhynchos a reticulate pattern. Fins hyaline. Distal half of anterior kalliurus Smith, 1945. Their material had also been collected pectoral rays dark brown. In largest specimens, caudal fi n in the same drainage as C. elegans (Kinabatangan) and with dark brown membranes between outermost principal shares the unique (within Crossocheilus) colour pattern of rays of each lobe. C. elegans, the blackish midlateral stripe extending from the tip of the gill opening to the middle of the base of the Distribution. – Crossocheilus elegans is currently known caudal fi n, separate from the dark brown dorsum by a pale from Sabah where it has been caught only in Segama and yellowish brown stripe. Nothing in Inger & Chin’s description Kinabatangan drainages. suggests that their material could belong to a species other than C. elegans. Habitat. – Crossocheilus elegans occurs in hill-stream habitats, usually near or in the riffl e zone in fast fl owing Crossocheilus elegans is not a member of the genus waters over a rocky bottom. At different sites, the following Epalzeorhynchos. The genus Epalzeorhynchos is diagnosed species have been found associated with C. elegans: Anguilla by the presence of a rostral lobe, a character shared with no borneensis (Anguillidae), Garra borneensis, Hampala sabana, other genus. The rostral lobe is an elongate conical structure, Lobocheilos unicornis, L. erinaceus, Paracrossochilus with a conspicuous conical tubercle at its tip and a series of acerus, Schismatorhynchos holorhynchos, Tor tambra, conical and starry tubercles along its lower edge. It is encased T. tambroides (Cyprinidae), Gastromyzon aequabilis, G. in a widened sublachrymal groove (which borders the rostral danumensis, G. lepidogaster, G. ornaticauda, G. pariclavis, fold) and surrounds the rostral barbel. The lobe is movable, G. spectabilis, Homaloptera stephensoni, Neogastromyzon and can rotate upwards along a more or less longitudinal axis crassiobex, Parhomaloptera microstoma (Balitoridae), to reach a position above the sublachrymal groove (Zhang & Glyptothorax major (Sisoridae), and Macrognathus keithi Kottelat, 2006; Yang & Winterbottom, 1998). This structure (Mastacembelidae). See Martin-Smith & Tan (1998) and is not present in C. elegans. Tan (2006) for details. 197 Kottelat & Tan: A new species of Crossocheilus from Northern Borneo Epalzeorhynchos kalliurus was originally described from the a conspicuous and contrasted yellowish stripe between the Mekong in northern Thailand on the basis of a single specimen blackish brown midlateral stripe and the dark brown dorsum (Smith, 1945: 264). Epalzeorhynchos kalliurus does not have (vs. a paler stripe may be present but never so contrasted and the rostral lobe that diagnoses the genus Epalzeorhynchos the dorsum is paler brown) and often margined above by a (see above). Banarescu (1986: 149) considered E. kalliurus narrow line formed by a row of darker scale pockets (vs. no as a synonym of C. cobitis (Bleeker, 1853), but he noted such line), scales on rows 1–2 under midlateral stripe and (p. 150) that the holotype had been examined by R. M. on dorsum with dark brown pockets, sometimes forming a Bailey who identifi ed it as C. reticulatus. On the contrary, reticulate pattern (vs. no conspicuous reticulate pattern), and Rainboth (1996: 119) considered C. calliurus as probably midlateral stripe not ending in a conspicuous small black distinct from C. cobitis, based on the lateral line scale blotch at the base of the caudal fi n (vs. blotch present). count and a different colour pattern. (Rainboth did not give additional details on material and localities since his work is an identifi cation guide and the format did not allow to list COMPARISON MATERIAL examined material or discussion). The colour pattern of C. kalliurus sensu Rainboth is made of a diffuse lateral stripe on Crossocheilus cf. cobitis: ZRC 37675, 1, 66.9 mm SL; ZRC posterior half of body, a diffuse blotch on the caudal peduncle 37687, 14, 22.4–64.1 mm SL; Borneo: Sabah: Kinabatangan and a sharply defi ned spot at the base of the caudal-fi n rays. drainage. – CMK 10427, 61, 24.8–48.2 mm SL; Indonesia: His fi gure was Smith’s (1945) fi gure of the holotype in the Borneo: Kapuas drainage. See Tan & Kottelat (2009) for a original description. Whether or not C. kalliurus is distinct list of additional material. from C. cobitis or C. reticulatus, the unique colour pattern of C. elegans (see diagnosis) distinguishes it at once from all. Crossocheilus reticulatus is endemic to the Mekong and ACKNOWLEDGEMENTS Chao Phraya drainages in Thailand, Cambodia and Laos; it has a large black blotch on the caudal peduncle, a reticulate We are very grateful to the following: Peter K. L. Ng, for his pattern on the fl ank and the dorsum, made of the black margin enthusiasm and support for our trips; and Keith M. Martin- of scales, and no midlateral black stripe. Smith and Y. Y. Goh, for their help in the fi eld, and two anonymous reviewers for their constructive comments. This Banarescu (1986) examined Inger & Chin’s (1962) material research has been partly funded by the National University and concluded that they are C. cobitis, based on the presence of Singapore. of two pairs of barbels and on the lateral line scale count. Tan & Kottelat (2009: 32) reviewed the species of Cobitis of Sumatra and discussed the identity of C. cobitis. Crossocheilus LITERATURE CITED cobitis is the most common species of the genus. It is a small species (up to 52 mm SL, mature at about 40–45 mm SL) Banarescu, P., 1986. A review of the species of Crossocheilus, commonly found in the lowlands, in murky waters, usually Epalzeorhynchos and Paracrossochilus (Pisces, Cyprinidae). with muddy bottom, under logs, fl oating houses, boats, etc. Travaux du Muséum d’Histoire Naturelle “Grigore Antipa”, 28: 141–161. It has two pairs of barbels; a continuous midlateral stripe from the tip of the snout to the base of the caudal fi n, with Bleeker, P., 1853. Nieuwe tientallen diagnostische beschrijvingen a conspicuous small blotch at the posterior extremity, faintly van nieuwe of weinig bekende vischsoorten van Sumatra. Natuurkundig Tijdschrift voor Nederlandsch-Indië, 5: 495– marked on the caudal fi n; a faint mark between the anus and 534. the anal-fi n origin in juveniles; and a narrow mouth. Inger, R. F. & P. K. Chin, 1962. The fresh-water fi shes of North Borneo. Fieldiana, Zoology, 45: 1–268. Several species had been confused under the name C. cobitis, all with a similar habitat in lowland murky waters (Tan Kottelat, M., 2001. Fishes of Laos. Wildlife Heritage Trust, & Kottelat, 2009: 32). Lim & Wong (1994: 44) in their Colombo. 198 pp. inventory of fi shes from the Kinabatangan basin recorded Lim, K. K. P. & A. Wong, 1994. Fishes of the Kinabatangan a ‘C. cobitis’ from the lower part of the drainage in turbid basin, Sandakan District, Sabah, East Malaysia. Sabah Museum water and with habits similar to that described above for C. Journal, 1(2): 39–71. cobitis. The identity of this species cannot be cleared without Martin-Smith, K. M. & H. H. Tan, 1998. Diversity of freshwater addressing also that of the other C. cobitis-like species on fi shes from eastern Sabah: Annotated checklist for Danum Borneo, which is beyond the scope of the present study [it can Valley and a consideration of inter- and intra-catchment be noted, however, that when compared to populations from variability. Raffl es Bulletin of Zoology, 46(2): 573–604. southern Borneo (e.g. Kapuas), the Kinabatangan species Rainboth, W. J., 1996. Fishes of the Cambodian Mekong. FAO, has a shorter snout, the dorsal-fi n origin conspicuously more Rome. 265 pp., 27 pls. forward, a slender caudal peduncle and a narrower mouth]. Roberts, T. R., 1989. The freshwater fi shes of western Borneo Crossocheilus elegans is known from the upper part of the (Kalimantan Barat, Indonesia). Memoirs of the California Kinabatangan drainage, in hill-stream habitats, with fast and Academy of Sciences, 14: 1–210. clear water. It is distinguished from C. cobitis (and the other Smith, H. M., 1945. The fresh-water fi shes of Siam, or Thailand. similar species) in having the midlateral stripe starting at the Bulletin of the United States National Museum, 188: i–xi + upper extremity of the gill opening (vs. at the tip of the snout), 1–622, 9 pls. 198 THE RAFFLES BULLETIN OF ZOOLOGY 2011 Tan, H. H., 2006. The Borneo Suckers. Revision of the Torrent Loaches Yang, J. X. & R. Winterbottom, 1998. Phylogeny and zoogeography of Borneo (Balitoridae: Gastromyzon, Neogastromyzon). Natural of the cyprinid genus Epalzeorhynchos Bleeker (Cyprinidae: History Publications (Borneo), Kota Kinabalu. 245 pp. Ostaiophysi). Copeia, 1998(1): 48–63. Tan, H. H. & M. Kottelat, 2009. The fi shes of the Batang Hari Zhang, E. & M. Kottelat, 2006. Akrokolioplax, a new genus of drainage, Sumatra, with description of six new species. Southeast Asian labeonine fishes (Teleostei: Cyprinidae). Ichthyological Exploration of Freshwaters, 20(1): 13–69. Zootaxa, 1225: 21–30. 199