AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 17 aqua, International Journal of Ichthyology A new species of glyptosternine catfish (Siluriformes: Sisoridae) from the Tawangchu River of Arunachal Pradesh, northeastern India Achom Darshan1, Santoshkumar Abujam2,4, Leki Wangchu2, Ram Kumar2, Debangshu Narayan Das2 and Raj Kumar Imotomba3 1) Department of Fisheries Resource Management, Pandit Deen Dayal Upadhyay Institute of Agricultural Sciences, Utlou-795134, Manipur, India. Email: [email protected] (AD). 2) Fishery and Aquatic Biology Laboratory, Department of Zoology, Rajiv Gandhi University, Rono Hills, Doimukh-791112, India. Email: [email protected] (LW). Email: [email protected] (RK); Email: [email protected] (DND). 3) Pandit Deen Dayal Upadhyay Institute of Agricultural Sciences, Utlou-795134, Manipur, India. Email: [email protected] (RKI). 4) Corresponding author: Email: [email protected] (SA). Received: 12 August 2018 – Accepted: 04 January 2019 Keywords Schwanzstieltiefe 6,4-6,8% SL; Länge der Fettflossenbasis Creteuchiloglanis, new species, Brahmaputra basin, India. 33,2-33,8% SL; Bauchflossenlänge 19,5-20,5% SL, 2+8 = 10 Kiemenreusen auf dem ersten Kiemenbogen; Kopftiefe Abstract 9,1-10,0% SL; Augendurchmesser 5,8-6,9% HL (Kopf - Creteuchiloglanis tawangensis, a new glyptosternine cat- länge). Diese neue Art ist die fünfte Art der Gattung Cre- fish, is described from the Tawangchu River at Tawang dis- teuchiloglanis, die vom Brahmaputra-Becken be schrieben trict, a headwater of the Manas River, Brahmaputra basin wurde. in Arunachal Pradesh, India. The new species differs from all congeners in having an unique combination of the fol- Sommario lowing characters: presence of pinnate-like rays on the an- Creteuchiloglanis tawangensis, un nuovo pesce gatto glip- terior margin of the first branched ray of anal fin, pectoral tosternino, è descritto dal fiume Tawangchu nel distretto fin not extending to the origin of pelvic fin, predorsal di Tawang, una sorgente del fiume Manas, bacino del length 31.3-32.5% SL, body depth at anus 10.7-11.1% Brahmaputra in Arunachal Pradesh, India. La nuova specie SL, caudal peduncle depth 6.4-6.8% SL, adipose-fin base differisce da tutti i congeneri per avere una combinazione length 33.2-33.8 % SL, pelvic fin length 19.5-20.5% SL, unica dei seguenti caratteri: presenza di raggi pinnati sul 2+8=10 gill rakers on the first branchial arch, head depth margine anteriore del primo raggio ramificato della pinna 9.1-10.0% SL, and eye diameter 5.8-6.9% HL. This is the anale, pinna pettorale che non raggiunge l'origine della fifth species of Creteuchiloglanis described from the pinna pelvica, lunghezza predorsale 31,3-32,5% SL, altez- Brahmaputra River basin. za del corpo all'ano 10,7-11,1% SL, altezza del peduncolo caudale 6,4-6,8% SL, lunghezza della base della pinna Zusammenfassung adiposa 33,2-33,8% SL, lunghezza della pinna pelvica Beschrieben wird Creteuchiloglanis tawangensis als neue 19,5-20,5% SL, 2 + 8 = 10 rastrelli branchiali sul primo Wels-Art der Unterfamilie Glyptosterninae vom arco branchiale, altezza della testa 9,1-10,0% SL e dia - Tawangchu-Fluss, einem Quellfluss des Flusses Manas im metro dell'occhio 5,8-6,9% HL. Questa è la quinta specie Brahmaputra-Becken in Arunachal Pradesh, Indien. Diese di Cretauchiloglanis descritta dal bacino del fiume neue Art unterscheidet sich von allen anderen Gat- Brahmaputra. tungsangehörigen durch die einzigartige Kombination fol- gender Merkmale: Vorhandensein feder-ähnlicher Flossen- strahlen am vorderen Rand des ersten verzweigten Flossen- INTRODUCTION strahls der Afterflosse; eine Brustflosse, die sich nicht bis Fishes of the genus Creteuchiloglanis Zhou et al. zum Ansatz der Bauchflosse erstreckt; prädorsale Länge (2011) are distributed in the upper Mekong River 31,3-32,5 % SL; Körpertiefe am After 10,7-11,1% SL; basin west to the Brahmaputra River basin (Zhou 17 aqua vol. 25 no. 1 - 25 January 2019 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 18 A new species of glyptosternine catfish (Siluriformes: Sisoridae) from the Tawangchu River of Arunachal Pradesh, northeastern India et al. 2011; Chu 1981; Ng 2004; Darshan et al. Creteuchiloglanis tawangensis n. sp. 2014). The genus is characterized by the presence (Fig. 1) of interrupted post-labial fold, broad isthmus, gill openings not extending ventrally onto undersur- Holotype: RGUMF 449, 152.0 mm SL: India: face of head, 14-16 branched pectoral-fin rays, Arunachal Pradesh state, Tawang District, lower lip not connected to the base of the maxillary Tawangchu River at Granger village, headwater of barbel by a skin flap, sulcus between the lip and the Manas drainage, Brahmaputra River basin, barbel, homodont dentition, teeth pointed, coni- 27°33’39.9”N, 91°53’15.7”E, elevation 1946 me- form in both jaws, premaxillary tooth patches con- ters, Leki Wangchu, 8 March 2015. tacting each other but not confluent, not extended Paratype: RGUMF 450, 138.7 mm SL: same data posterolaterally, laterally blunt; dilator operculi as holotype. muscle and levatoroperculi muscle contacting each Diagnosis: Creteuchiloglanis tawangensis n. sp. other, broad anterior end of sternohyoideus mus- differs from all congeners in having a unique com- cle, its width almost equal to the width in the axilla bination of the following characters: presence of of the pectoral fin, adductor pelvicalis superficialis pinnate-like rays on the anterior margin of the first muscle not contacting its antimere at the midline branched ray of anal fin, pectoral fin not extending (Zhou et al. 2011). Eight species are currently rec- to the origin of pelvic fin, predorsal length 31.3- ognized under the genus Creteuchiloglanis, viz. C. 32.5% SL, body depth at anus 10.7-11.1% SL, arunachalensis Sinha & Tamang, C. payjab Dar- caudal peduncle depth 6.4-6.8% SL, adipose-fin shan et al., C. kamengensis (Jayaram) and C. base length 33.2-33.8% SL, pelvic-fin length 19.5- bumdelingensis Thoni & Gurung from the 20.5% SL, 2+8=10 gill rakers on the first branchial Brahmaputra River basin; C. longipectoralis Zhou arch, head depth 9.1-10.0% SL, and eye diameter et al. from the Mekong River basin; C. gongshanen- 5.8-6.9% HL. See the discussion, for a detailed sis (Chu) from the Salween River basin; C. comparison with congeners. brachypterus Zhou et al. from the Irrawaddy River Description: Morphometric data in Table I. Dor- basin; C. macropterus Ng from both the Salween sal profile rising gradually from tip of snout to ori- and the Irrawaddy River basins. gin of dorsal fin, then almost straight to adipose- During a recent ichthyological survey of the fin origin, and from there gentle sloping ventrally Tawangchu River (a headwater of Manas River, towards caudal peduncle. Ventral profile straight to Brahmaputra River basin) at Tawang district of anal-fin origin, and from there gentle sloping dor- Arunachal Pradesh, India, two specimens of glyp- sally towards caudal peduncle. Head and abdomi- tosternine catfishes with characteristics consistent nal region strongly depressed and broad, then lat- with the diagnosis of the genus Creteuchiloglanis erally compressed towards caudal peduncle. were collected, and a further examination revealed Gill opening small and short, extending from it to an undescribed species, which is herein de- posttemporal region to middle of pectoral-fin base, scribed. not extending to undersurface of head. First branchial arch with 2+8=10 gill rakers. Eye small MATERIA LS AND METHODS and rounded, subcutaneous, located near to dorsal Measurements were made on the left side of spec- midline of head. Mouth inferior and transverse, imens with dial calipers to the nearest 0.1 mm, fol- lips papillated. Post labial groove interrupted, ter- lowing Zhou et al. (2011). Measurements of the minated near base of inner mandibular barbel. An- body parts and the subunits of head were expressed terior margin of premaxillary tooth band exposed as proportions of standard length (SL) and head when mouth is closed, left and right premaxillary length (HL) respectively. Number in parenthesis tooth patches placed in contact with each other but after a count indicates the frequency of that count. not confluent, junction of anterior margin with a Data from species not listed in the comparative notch fill with papillated skin of upper lip. Oral material were taken from the literature (Zhou et al teeth cone shaped, embedded in skin exposing 2011; Ng 2004; Sinha & Tamang 2014; Thoni & their pointed tips, arranged in irregular rows, teeth Gurung 2018).The collected specimens were de- on lower jaw sharper than upper. posited in the Rajiv Gandhi University Museum of Barbels in four pairs, all flattened. Anterior and Fishes (RGUMF), Doimukh, Arunachal Pradesh. posterior nostrils separated by nasal barbel. Nasal barbel not reaching to anterior rim of orbit; maxil- aqua vol. 25 no. 1 - 25 January 2019 18 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 19 Achom Darshan, Santoshkumar Abujam, Leki Wangchu, Ram Kumar, Debangshu Narayan Das and Raj Kumar Imotomba lary barbel extending beyond origin of pectoral fin, gin broadly rounded, its first ray broadened and its distal tip sharply pointed, posterior margin with entire length of ventral surface ornamented with thin fringing, skin flap. Outer mandibular barbel regular striae. Anal fin with ii,5 (2) rays, anterior inserted postero-lateral to inner mandibular barbel, margin of first branched ray bears pinnate like its distal tip extend to origin of pectoral-fin when rays, fin origin closer to caudal-fin base than to adpressed. Inner mandibular barbel shorter, nearly pelvic-fin origin. Anus nearer to anal-fin origin half of length of outer mandibular barbel length. than to pelvic-fin origin. Caudal fin rounded with Dorsal fin with no spine, bearing i,6 (2) rays, dis- i,15,i (2) rays.