Journal of Fish Biology (2006) 68 (Supplement A), 101–118 doi:10.1111/j.1095-8649.2006.01019.x,availableonlineathttp://www.blackwell-synergy.com The identity of Batasio tengana (Hamilton, 1822), with the description of two new species of Batasio from north-eastern India (Teleostei: Bagridae) H. H. NG * Fish Division, Museum of Zoology, University of Michigan, 1109 Geddes Avenue, Ann Arbor, Michigan 48109-1079, U.S.A. (Received 7 December 2004, Accepted 22 October 2005) Batasio tengana is redescribed on the basis of fresh material and a neotype designated. Two new species are described: Batasio fasciolatus n. sp. is described from material previously identified as B. tengana from the Brahmaputra River drainage and can be distinguished from congeners in having a combination of five to six vertical dark brown bars on a light brown body, dorsal-spine length 13Á6–16Á8% standard length (LS), pectoral-spine length 12Á7–14Á3% LS, and eye diameter 16Á5–18Á8% head length (LH). Batasio spilurus n. sp. is described from the Brahmaputra River drainage in Assam and can be distinguished from congeners in having a short adipose-fin base (12Á6–12Á8 v.14Á5–33Á3% LS) and more # slender caudal peduncle (5Á7–6Á2 v.6Á7–11Á8% LS). 2006 The Fisheries Society of the British Isles Key words: Brahmaputra; freshwater catfish; Ganges; India; Nepal. INTRODUCTION Species of Batasio Blyth, 1860, are small bagrid catfishes inhabiting the fresh waters of south and south-east Asia. They typically have laterally compressed heads and bodies, at least 35 vertebrae, and lack both an oar-like adipose fin and a prominent anterolateral process of the pelvic girdle. Batasio species are found only in hill- streams and upper reaches of large rivers. Twelve species of Batasio are considered valid (Ng & Edds, 2004): B. batasio (Hamilton, 1822), B. tengana (Hamilton, 1822), B. affinis Blyth, 1860, B. dayi (Vinciguerra, 1890), B. merianiensis, (Chaudhuri, 1913), B. havmolleri (Smith, 1931), B. travancoria (Hora & Law, 1941), B. pakista- nicus (Mirza & Jan, 1989), B. tigrinus (Ng & Kottelat, 2001), B. elongatus (Ng, 2004), B. sharavatiensis (Bhatt & Jayaram, 2004) and B. macronotus (Ng & Edds, 2004). During a recent ichthyological survey of north-east India, specimens of two Batasio species were obtained. A study of this material revealed that one of the species matched the original description and illustration of B. tengana,butwas unlike specimens previously reported as B. tengana. Comparison with material previously identified as B. tengana and other material collected from north-east *Tel.: þ1 734 6472192; fax: þ1 734 7634080; email: [email protected] 101 # 2006 The Fisheries Society of the British Isles 102 H. H. NG India and Nepal showed that these specimens reported as B. tengana in previous studies are misidentifications. The purpose of this study was to redescribe B. tengana and designate a neotype, and to describe two new species from north-east India. MATERIALS AND METHODS Measurements were made point-to-point with dial callipers and recorded to 0Á1 mm. Ng & Kottelat (2001) was followed for all measurements and counts. Numbers in parentheses after measurements or meristic counts refer to the number of specimens observed with the stated measurement or count. Asterisks following a particular meristic count indicates the values for the neotype (for B. tengana) or the holotypes (for B. fasciolatus n. sp. and B. spilurus n. sp.). Institutional codes follow Eschmeyer (1998). RESULTS BATASIO TENGANA (HAMILTON, 1822) (FIG.1) Pimelodus tengana Hamilton, 1822: 176, Pl. 39 Fig. 58 (type locality: Goalpara) (a) (b) FIG.1. Batasio tengana: (a) Neotype, UMMZ 244796, 43Á4mm LS; India: West Bengal, Tista River and (b) illustration from Hamilton (1822: Pl. 39 Fig. 58). # 2006 The Fisheries Society of the British Isles, Journal of Fish Biology 2006, 68 (Supplement A), 101–118 BATASIO TENGANA AND TWO NEW BATASIO 103 Bagrus tengana Cuvier & Valenciennes, 1840: 433. Batasio tengana Blyth, 1860: 150. Macrones tengana Gu¨nther, 1864: 84. Gagata tengana Day, 1877: 493; Day, 1889: 210. Material examined UMMZ 244796, neotype, designated here 43Á4 mm standard length (LS) India: West Bengal: Tista River at Tista barrage; 264501000 N; 883401100 E. KU 28534 (1), 31Á5mm LS; KU 35240 (5), 30Á4–39Á4mm LS; KU 35256, 0 00 53Á5mm LS; Nepal: Saptari/Sunsari, purchased at Kosi barrage, 26 31 30 N; 0 00 86 56 00 E. KU 28685 (1), 36Á0mm LS; Nepal: Kanchanpur, Chandhar River, confluence of three rivers (Chaudhar, Bahuri, Gobraiya) at Royal Shuklaa Phantaa Wildlife Reserve, 284300000 N; 801200000 E. OSUS 17365 (2), 35Á8– 36Á6mm LS; Nepal: Nawalparasi, Narayani River at Toadi Ghat. OSUS 15812 (2), 43Á8–45Á9mm LS; Nepal: Nawalparasi, borrow ditch west of Tribeni. Diagnosis Batasio tengana can be distinguished from all congeners except B. pakistanicus and B. spilurus n. sp. in having a shorter adipose-fin base (14Á5–17Á5 v.22Á1– 35Á1% LS) and the presence (v. absence) of a dark mid-dorsal stripe. Batasio tengana appears to reach a smaller size than other congeners (maximum size to c.55v. to 101 mm LS), except for B. pakistanicus and B. spilurus n. sp., which are known to reach 35 and 45 mm LS respectively. Batasio tengana differs from B. pakistanicus in the pectoral fin rays not reaching (v. reaching) the pelvic-fin origin, and from B. spilurus n. sp. in having a longer adipose-fin base (14Á5–17Á5 v.12Á6–12Á8% LS), a deeper caudal peduncle (6Á7–8Á2 v.5Á7–6Á2% LS) a nar- rower head (12Á5–14Á5 v.16Á4–16Á5% LS), and a more rounded, bulbous snout when viewed laterally [Fig. 2(a)]. Description Morphometric data are given in Table I. Body moderately compressed lat- erally, slender in individuals <50 mm LS and moderately deep in the individual >50 mm LS. Dorsal profile rising evenly and gently from tip of snout to origin of dorsal fin, then sloping gently ventrally from dorsal fin to end of caudal peduncle. Ventral profile flat to anal-fin base, then sloping gently dorsally from anal-fin base to end of caudal peduncle. Anus and urogenital openings located at vertical through middle of appressed pelvic fin. Skin smooth. Lateral line complete and midlateral. Vertebrae 19 þ 18 (2), 19 þ 19 (9) or 19 þ 20* (2). Head slightly depressed and narrow. Bony elements of dorsal surface of head covered with thin skin. Anterior nostril tubular, separated from posterior nostril by distance in excess of width of nasal-barbel base. Sensory pores on head enlarged and prominent. Eye ovoid, horizontal axis longest; located entirely in dorsal half of head. Gill openings wide, extending from posttemporal to beyond isthmus. Gill membranes free from isthmus. Mouth inferior, premaxillary tooth band not exposed when mouth closed. Oral teeth small and villiform, in irregular rows on all tooth-bearing surfaces. Premaxillary tooth band rounded, of equal width throughout. Dentary tooth # 2006 The Fisheries Society of the British Isles, Journal of Fish Biology 2006, 68 (Supplement A), 101–118 104 H. H. NG TABLE I. Biometric data for Batasio tengana (n ¼ 13) Neotype Range Mean Æ S.D. In % standard length (LS) Predorsal length 35Á735Á7–40Á037Á1 Æ 1Á28 Preanal length 66Á665Á5–69Á767Á2 Æ 1Á49 Prepelvic length 47Á545Á7–51Á449Á1 Æ 1Á86 Prepectoral length 24Á922Á9–25Á824Á6 Æ 1Á08 Length of dorsal-fin base 13Á810Á5–16Á414Á4 Æ 1Á61 Length of dorsal spine 10Á410Á4–16Á114Á5 Æ 1Á75 Length of anal-fin base 18Á015Á3–20Á418Á3 Æ 1Á79 Length of pelvic fin 15Á213Á7–17Á816Á0 Æ 1Á16 Length of pectoral fin 15Á415Á4–19Á718Á6 Æ 1Á37 Length of pectoral spine 14Á313Á9–17Á115Á5 Æ 0Á95 Length of caudal fin 22Á421Á9–29Á726Á3 Æ 2Á76 Length of adipose-fin base 16Á414Á5–17Á515Á5 Æ 0Á96 Dorsal to adipose distance 21Á715Á1–23Á319Á5 Æ 2Á21 Post-adipose distance 18Á415Á4–20Á217Á4 Æ 1Á36 Length of caudal peduncle 15Á414Á0–20Á016Á4 Æ 1Á52 Depth of caudal peduncle 7Á66Á7–8Á27Á3 Æ 0Á52 Body depth at anus 13Á88Á6–18Á113Á2 Æ 2Á21 Head length (LH)25Á623Á8–28Á825Á8 Æ 1Á37 Head width 14Á112Á5–14Á513Á6 Æ 0Á54 Head depth 14Á713Á2–16Á414Á7 Æ 1Á01 In % LH Snout length 30Á630Á6–40Á035Á1 Æ 2Á76 Interorbital distance 21Á621Á6–29Á925Á8 Æ 2Á50 Eye diameter 25Á221Á9–32Á126Á8 Æ 2Á93 Length of nasal barbel 32Á412Á8–56Á141Á3 Æ 13Á68 Length of maxillary barbel 65Á865Á8–94Á783Á9 Æ 9Á94 Length of inner mandibular barbel 27Á012Á8–41Á121Á2 Æ 8Á75 Length of outer mandibular barbel 37Á831Á6–53Á140Á7 Æ 6Á92 band much narrower than premaxillary tooth band at symphysis, tapering laterally. Barbels in four pairs. Maxillary barbel long and slender, extending to base of pectoral spine. Nasal barbel slender, extending to midway between posterior orbital margin and gill opening. Inner mandibular-barbel origin close to midline, extending to one-quarter of distance between its base and base of pectoral spine. Outer mandibular barbel originating posterolateral of inner mandibular barbel, extending to midway between its base and base of pectoral spine. Dorsal fin with spinelet, spine, and 7 (13) rays. Origin of dorsal fin at point through anterior two-fifths of body. Dorsal-fin margin convex. Dorsal-fin spine moderately long, straight, and slender, with smooth anterior and posterior edges. Pectoral fin with stout spine, sharply pointed at tip, and 6 (4), 7 (2) or 8* (7) rays. Anterior spine margin smooth; posterior spine margin with nine to 12 small serrations along entire length. Pectoral-fin margin straight anteriorly, convex posteriorly. # 2006 The Fisheries Society of the British Isles, Journal of Fish Biology 2006, 68 (Supplement A), 101–118 BATASIO TENGANA AND TWO NEW BATASIO 105 (a) (b) FIG. 2. Lateral views of heads of: (a) Batasio tengana, OSUS 15812, 43Á8mmLS and (b) B. spilurus n. sp., holotype, ZRC 49133, 42Á0mm LS. Scale bar ¼ 5mm. Pelvic-fin origin at vertical through posterior end of dorsal-fin base, with i,5 (13) rays and slightly convex margin; tip of appressed fin not reaching anal-fin origin.