AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 17

aqua, International Journal of Ichthyology

A new species of glyptosternine (Siluriformes: ) 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 beschrieben 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 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 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. Skin rugose dorsally, heavily tuber- tal margin slightly convex, tip of adpressed dorsal culated ventrally from throat to middle of pelvic- fin crossed base of last pelvic-fin ray. Adipose fin fin base. Lateral line complete and mid-lateral in long, anterior margin rising gently and then runs position. parallel to dorsal midline of body, terminate at C o l o r a t i o n i n a l c o h o l : Overall body middle of caudal peduncle with narrow notch. colour brownish to greyish with pale yellowish Pectoral fin large, with i,14* or i,15 (1) rays, non- patch around posterior base of adipose fin, ventral ossified first ray broadened and ventrally orna- surfaces of head and belly pale-creamish. Distal mented with regular striae, distal fin margin broad- two-thirds of adipose fin pale yellowish. Bases of ly rounded and not extending to pelvic-fin origin. first and the last fin rays of pair fins with pale spots. Pelvic fin enlarge, with i,5 (2) rays, distal fin-mar- Distal margin of all fins except caudal fin with

Fig. 1a-c. Creteuchiloglanis tawangensis n. sp., RGUMF: 449, 152.0 mm SL, holotype: a. lateral, b. dorsal, and c. ventral views.

19 aqua vol. 25 no. 1 - 25 January 2019 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 20

A new species of glyptosternine catfish (Siluriformes: Sisoridae) from the Tawangchu River of Arunachal Pradesh, northeastern India

Table I. Morphometric data for Creteuchiloglanis tawangensis n. sp. and its congeners.

C. tawangensis C. arunachalensis C. payjab C. bumdelingensis C. kamengensis C. brachypterus C. gongshanensis C. longipectoralis C. macropterus n. sp. (Sinha & (Ng 2004) Tamang 2014) (Zhou et al. 2011)

Standard length (mm) 138.7-152.0* 87.1 110.2-156.0 28.6-39.1 61.6-155.0 71.1-146.4 86.4-117.6 69.5-177.4 61.5-176.0 % Standard length Predorsal length 31.3*-32.5 35.7 30.4-33.5 31.9-38.3 34.5-37.5 31.7-35.7 34.8-37.8 29.5-35.8 33.0-36.7 Preanal length 76.9*-80.0 77.3 76.4-78.6 72.1-75.4 72.9-77.8 72.5-77.8 77.3-80.0 74.0-79.0 70.3-77.3 Prepelvic length 39.2-40.0* 45.4 41.6-43.1 40.3-43.4 39.4-43.1 39.6-46.3 38.1-43.4 36.4-42.5 37.0-42.2 Prepectoral length 14.7*-15.0 19.0 16.8-20.5 17.6-21.3 16.9-17.5 10.0-16.1 10.9-17.7 11.8-18.9 18.3-21.4 Dorsal-fin base length 11.5-11.6* 12.1 10.2-11.9 7.9-11.8 11.8-13.6 8.3-12.4 9.1-10.6 11.8-13.6 9.8-10.8 Body depth 10.9*-11.2 15.1 11.4-13.0 11.6-17.2 – 10.0-16.8 12.8-16.0 8.5-13.5 – Body depth at anus 10.7*-11.1 11.6 9.6-11.9 – 9.8-14.7 9.6-11.8 10.3-12.8 7.8-8.1 9.5-12.6 Head length 22.5*-22.7 25.4 22.7-25.9 23.5-26.8 19.6-25.3 21.7-27.5 25.2-27.6 19.9-27.1 23.5-27.8 Head width 20.4-21.4* 23.6 20.0-23.1 – 19.6-21.8 19.4-24.7 21.4-25.2 18.9-23.7 19.3-22.2 Head depth 9.1*-10.0 11.7 10.2-12.3 – 10.1-11.8 9.0-11.8 10.0-13.6 7.2-8.8 10.6-12.4 Caudal-peduncle length 16.6*-17.8 16.8 15.7-17.7 17.0-19.7 16.0-17.9 17.2-21.3 14.6-17.5 13.8-20.4 17.6-20.0 Caudal-peduncle depth 6.4*-6.8 8.9 6.1-6.9 6.4-7.9 6.1-6.5 6.5-8.0 3.8-4.6 6.5-8.9 6.8-7.4 Dorsal to adipose 16.9-18.9* 20.0 14.0-19.8 11.4-14.7 12.5-20.0 18.1-25.0 17.9-22.3 20.2-30.0 14.0-17.2 distance Pre-adipose distance 59.8*-61.1 63.9 57.5-65.2 – – 60.2-70.8 60.1-65.5 57.2-70.6 – Post-adipose distance 8.5*-9.1 10.1 7.7-13.2 – 8.2-8.8 9.1-11.3 8.6-10.9 7.0-8.9 9.0-10.1 Dorsal-fin length 15.1-15.2* 16.1 13.0-16.4 – – 12.3-17.7 15.8-20.3 10.4-19.6 – Pectoral-fin length 22.9*-24.1 23.1 23.5-25.8 26.4-28.2 25.0-28.7 18.5-21.8 25.3-28.1 19.8-29.9 23.4-27.0 Pelvic-fin length 19.5*-20.5 18.8 19.5-20.5 18.2-21.6 18.5-21.9 14.5-18.7 19.2-22.2 18.6-24.2 18.9-22.4 Anal-fin length 11.5-12.5* 12.8 11.8-13.4 – – 11.1-15.3 10.5-12.9 11.1-16.1 5.7-6.8 Anal-fin base length 5.5-5.6* 6.6 4.2-5.6 4.3-6.9 6.1-8.8 4.8-8.6 4.7-5.4 6.1-8.8 Caudal-fin length 14.6* 15.0 12.6-14.2 – 13.8-16.6 11.2-12.9 14.7-17.8 12.1-19.9 14.3-16.4 Adipose-fin base length 33.2-33.8* 25.9 28.8-31.9 29.3-36.3 32.7-37.3 28.4-33.7 26.2-32.7 25.3-33.5 31.8-37.0 % Head length Snout length 55.8*-58.5 54.8 51.5-56.1 – 54.0-56.3 50.1-61.9 51.6-56.8 46.7-62.5 50.3-56.5 Eye diameter 5.8*-6.9 6.8 3.9-7.3 8.3-12.8 5.1-6.4 7.0-12.0 5.8-6.7 4.4-8.3 5.4-7.6 Interorbital width 23.3*-23.4 22.5 21.6-24.6 – 21.2-28.2 22.9-27.8 23.4-29.1 20.2-32.4 24.6-30.2 Maxillary barbel length 73.4-79.8* 71.2 88.3-95.0 79.3-98.2 75.2-91.1 85.4-92.9 85.9-91.8 85.7-99.8 70.4-79.7 Inner mandibular 17.3*-21.5 19.1 9.3-17.3 11.2-14.0 17.3-25.3 17.1-18.7 19.0-20.4 19.7-24.7 19.3-26.5 barbel length Outer mandibular 22.8-25.7* 32.1 19.4-26.7 20.8-26.5 23.1-34.5 25.2-31.5 27.3-30.5 29.7-35.5 27.5-36.1 Nasal barbel length 24.0-25.7* 32.4 17.2-25.6 25.0-42.4 pale-creamish margins. Basal half of caudal fin pale caudal fin of glyptosternoid (= glyptosternine) fish- creamish, distally brownish. es also bears the pinnate-like rays, each pinnate ray Etymology: The species epithet is derived from corresponds to one fin-ray segment (Chen & the type locality of the new species. Lundberg 1995). In Amblyceps, pinnate-like rays Distribution: Creteuchiloglanis tawangensis is (approximately four pinnate rays correspond to presently known only from its type locality, the each segment of fin ray) are present along the ante- Tawangchu River (Fig. 2) at Tawang district, a rior margin of procurrent and simple principal rays headwater of Manas River (Brahmaputra River (Chen & Lundberg 1995). In some amblycipitids basin) in Arunachal Pradesh, India (Fig. 3). of Indian subcontinent presenting a forked caudal fin,the median caudal-fin rays bears numerous cen- DISCUSSION trally projecting hooks (= pinnate-like rays of Ng The first ray of the pectoral and pelvic fins of & Kottelat 2000) on its proximal region (Darshan glyptosternoid (= glyptosternine) fishes bears pin- et al. 2016; Ng & Kottelat 2018). In the present nate-like soft cartilaginous rays along the anterior study, we observed the pinnate like rays along the margin (Hora & Silas 1952).The anterior margins anterior margin of the second simple and the first of some procurrent and simple principal rays of branched rays of anal fin in three congeners of Cre-

aqua vol. 25 no. 1 - 25 January 2019 20 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 21

Achom Darshan, Santoshkumar Abujam, Leki Wangchu, Ram Kumar, Debangshu Narayan Das and Raj Kumar Imotomba

Fig. 2. Tawangchu River at Tawang, Arunachal Pradesh, the type locality of Creteuchiloglanis tawangensis n. sp. Photo by A. Darshan.

Fig. 3. Map showing the type localities of four species of Creteuchiloglanis in the Brahmaputra River basin: Creteuchiloglanis tawangensis n. sp. (star); C. kamengensis (square); C. payjab (circle), and C. arunachalensis (triangle). Redrawn from Darshan et al. 2016.

21 aqua vol. 25 no. 1 - 25 January 2019 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 22

A new species of glyptosternine catfish (Siluriformes: Sisoridae) from the Tawangchu River of Arunachal Pradesh, northeastern India

teuchiloglanis from the Brahmaputra River basin, of Creteuchiloglanis viz. Creteuchiloglanis tawangen- viz. C. tawangensis, C. kamengensis and C. payjab sis, C. kamengensis, C. payjab, C. arunachalensis and (Fig. 4). The location and pattern of arrangement C. bumdelingensis. The new species differs from C. of these pinnate-like rays in the anterior anal-fin kamengensis and C. payjab by the presence (vs. ab- rays tend to show some taxonomic value. In C. sence) of pinnate-like rays on the anterior margin tawangensis, pinnate-like rays are observed in the of the first branched ray of anal fin and by its more anterior margin of first branched ray, while in C. depressed head (depth 9.1-10.0% SL vs. 10.1- kamengensis and C. payjab these pinnate-like rays 12.3% SL). Further, the new species differs from are present along the anterior margin of second C. kamengensis in having a pectoral fin not reach- simple ray. However, we were not able to confirm ing (vs. reaching) to the origin of pelvic fin, an an- the presence or absence of the pinnate-like rays on teriorly positioned dorsal fin (predorsal length the anal-fin rays of C. arunachalensis due to un- 31.3-32.5 % SL vs. 34.5-37.5 % SL), and more gill availability of specimen.The presence of pinnate- rakers on the first branchial arch (10 vs. 8), and a like rays in the anal-fin rays of C. macropterus has shorter dorsal-fin base (11.5-11.6% SL vs. 11.8- been confirmed from its holotype (H. H. Ng, pers. 13.6% SL). Furthermore, the new species differs comm.). The function of the pinnate structures in from C. payjap in having a shorter prepectoral the anal fin might be to protect the anterior fin rays length (14.7-15.0% SL vs. 16.8-20.5% SL), pre- from wear and tear during movements.We ob- pelvic length (39.2-40.0% SL vs. 41.6-43.1% SL), served and confirmed that the pinnate-like rays are and maxillary barbel (73.4-79.8% HL vs. 88.3- absent in the anal-fin rays of Oreoglanis, Exostoma, 95.0% HL), a longer adipose-fin base (33.2-33.8 and Parachiloglanis. % SL vs. 28.2-31.9% SL), by the absence of a With the description of the new species, the whitish patch basally at the posterior margin of Brahmaputra River basin has five sympatric species skin flap of maxillary barbel (vs. presence), and abc

Fig. 4. Pinnate-like rays on the anterior anal-fin rays of: a. C. tawangensis n. sp., RGUMF 449, 152.0 mm SL, holotype; b. C. payjab, RGUMF 251, 155 mm SL; c. C. kamengensis, RGUMF 441, 108 mm SL. [Sr: Simple ray, Plr: Pinnate-like rays, Br1: First branched ray]

aqua vol. 25 no. 1 - 25 January 2019 22 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 23

Achom Darshan, Santoshkumar Abujam, Leki Wangchu, Ram Kumar, Debangshu Narayan Das and Raj Kumar Imotomba

highly papillated skin on isthmus and gular regions of pelvic fin (vs. reaching), smaller eye (diameter (vs. skin on isthmus and gular regions with few 5.8-6.9% HL vs. 8.3-12.8 % HL), shorter head papillae) (Fig. 5). The new species differs from C. (22.5-22.7% SL vs. 23.5-26.8 % SL) and prepelvic arunachalensis by its smaller head (length 22.5- length (39.2-40.0% SL vs. 40.3-43.4% SL), slen- 22.7% SL vs. 25.4 % SL, width 20.4-21.4% SL vs. der body (depth 10.9-11.2% SL vs. 11.6-17.2% 23.6, depth 9.1-10.0 % SL vs. 11.7% SL), shorter SL),and more anal-fin branched rays (4 vs. 5). predorsal length (31.3-32.5 % SL vs. 35.7% SL), Among the congeners known from the Irrawaddy prepectoral (14.7-15.0% SL vs. 19.0% SL), pre- River and the Salween River basins, C. tawangensis pelvic (39.2-40.0% SL vs. 45.4% SL), more slen- is distinguished from C. macropterus in having a der body (depth at dorsal origin 10.9-11.2% SL vs. shorter (22.5-22.7% SL vs. 23.5-27.8% SL) and 15.1% SL, depth at anus 10.7-11.1% SL vs. shallower (depth 9.1-10.0% SL vs. 10.6-12.4% 11.6% SL) and caudal penduncle depth (6.4-6.8 SL) head, a shorter predorsal length (31.3-32.5% % SL vs. 8.9% SL), longer adipose-fin base (33.2- SL vs. 33.0-36.7% SL), prepectoral length (14.7- 33.8% SL vs. 25.9% SL), maxillary barbel (73.4- 15.0% SL vs. 18.3-21.4% SL), and outer man - 79.8% HL vs. 71.2% SL), and snout (55.8-58.5% dibular barbel (22.8-25.7% HL vs. 27.5-31.6% HL vs. 54.8% SL). Creteuchiloglanis tawangensis SL), a longer dorsal-fin base (11.5-11.6% SL vs. differs from C. bumdelingensis by its shorter pec- 9.8-10.8% SL), and by the absence of a pale toral fin (22.9-24.1% SL vs. 26.4-28.2% SL), dis- yellowish spot on the occipital region (vs. pres- tal margin of pectoral fin not reaching to the base ence). The new species can be distinguished from

Fig. 5a-d. Ventral views of head: a. C. payjab, RGUMF 0259, 172.2 mm SL, holotype; b. C. tawangensis, RGUMF 450, 138.7 mm SL, paratype; c.C. kamengensis, RGUMF 441, 108 mm SL. Photos by A. Darshan. d. C. arunachalensis, ZSI/V/APRC/P-844, 87.1 mm SL, holotype. Photo S. K. Abujam.

23 aqua vol. 25 no. 1 - 25 January 2019 AQUA 25-1_ok.qxp_AQUA 05/02/19 10:45 Pagina 24

A new species of glyptosternine catfish (Siluriformes: Sisoridae) from the Tawangchu River of Arunachal Pradesh, northeastern India

C. brachypterus by its longer pectoral fin (22.9- 31.01.2017), and also to both the Center with Po- 24.1% SL vs. 18.5-21.8% SL), pelvic fin (19.5- tential for Excellence in Biodiversity (CPEB-II) 20.5% SL vs. 14.5-18.7% SL), caudal fin (14.6% and the Department of Zoology, Rajiv Gandhi SL vs. 11.2-12.9% SL), shorter maxillary barbel University, Itanagar, for providing all the required (73.4-79.8% HL vs. 85.4-92.9% HL) and smaller research facilities. The authors are also indebted to eye diameter (5.8-6.9% HL 7.0-12.0% HL). the chief of Granger village for granting permission The new species differs from C. gongshanensis in for sampling in the Tawangchu river, from where having a shorter head length (22.5-22.7% SL vs. the new species was discovered. We are very thank- 25.2-27.6% SL), predorsal length (31.3-32.5% SL ful to H. H. Ng for helpful comments on the man- vs. 34.8-37.8% SL), pectoral-fin length (22.9- uscript and also for providing osteological data of 24.1% SL vs. 25.3-28.1% SL), maxillary barbel the holotype of C. macropterus. (73.4-79.8% HL vs. 85.9-91.8% HL), outer mandibular barbel (22.8-25.7% HL vs. 27.3- REFERENCES 30.5% HL); a longer dorsal-fin base (11.5-11.6% CHEN, X. P. & LUNDBERG J. G. 1995. Xiurenbagrus, a new SL vs. 9.1-10.6% SL), anal-fin base (5.5-5.6% SL genus of amblycipitide catfishes (Teleostei: Siluriformes), and phylogenetic relationships among the genera of Am- vs. 4.7-5.4% SL), and adipose-fin base (33.2- blycipitidae. Copeia 1995 (4): 780-800. 33.8% SL vs. 26.2-32.7% SL), and a deeper caudal CHU, X.-L. 1981. Taxonomic revision of the genera peduncle (6.4-6.48% SL vs. 3.8-4.6% SL). Pareuchiloglanis and Euchiloglanis. Zoological Research 2: Creteuchiloglanis tawangensis differs from C. 25-31. longipectoralis (from the Mekong River basin) by its DARSHAN, A., DUTTA, R., KACHARI, A., GOGOI, B., ARAN, deeper head (9.1-10.0% SL vs. 7.2-8.8% SL), deep- K. & DAS, D. N. 2014. A new species of glyptosternine er body (depth at anus 10.7-11.1% SL vs. 7.8-8.1% catfish (Siluriformes: Sisoridae) from Yomgo River, SL), shorter dorsal to adipose distance (16.9-18.9% Arunachal Pradesh, India. aqua, International Journal of SL vs. 20.2-30.0% SL), anal-fin base length (5.5- Ichthyology 20 (2): 73-80. DARSHAN, A., KACHARI, A., DUTTA, R., GANGULY, A. & 5.6% SL vs. 6.1-8.8% SL), outer mandibular length DAS, D. N. 2016. Amblyceps waikhomi, a new species of (22.8-25.7% HL vs. 29.7-35.5% HL), and longer catfish (Siluriformes: Amblycipitidae) from the Brahma- maxillary barbel (73.4-79.8% HL vs. 85.7-99.8% putra drainage of Arunachal Pradesh, India. PLoS One HL), and more dorsal-fin branched rays (6 vs. 5). 11(2): e0147283. Comparative material: All from India. Cre- HORA, S. L. & SILAS, E. G. 1952. Notes on fishes in the In- teuchiloglanis kamengensis: MUMF 6200, 1, 86.0 dian Museum. XLVII. Revision of the Glytosternoid fishes mm SL, Arunachal Pradesh (AP), Rupa, Kameng of the family Sisoridae with description of new genera and species. Records of the Indian Museum 49: 5-29. River, Brahmaputra basin. RGUMF 441, 1, 108 Ng, H. H. 2004. Two new glyptosternine catfishes mm SL, Kameng River at Sergoan, West-Kameng (Teleostei: Sisoridae) from Vietnam and China. Zootaxa district, AP. RGUMF 448, 1, 114 mm SL, Kameng 428: 1-12. River at Rupa, West Kameng district, AP. Cre- NG, H. H. & KOTTELAT, M. 2000. A review of the genus teuchiloglanis payjab: RGUMF 249, holotype, 172 Amblyceps (Osteichthyes: Amblycipitidae) in Indo-china, mm SL, Yomgo River at Mechuka, a tributary of with descriptions of five new species. Ichthyological Explo- Siang River, Brahmaputra River basin, AP. ration of Freshwaters 11: 335-348. RGUMF 251-254, 4, 110.2-155.1mm SL; NG, H. H. & KOTTELAT, M. 2018. Amblyceps improcerum, a new sisoroid catfish from Kachin State, Myanmar ZSI/V/APRC/P-921, 1, 153.5 mm SL, same data (Teleostei: Siluriformes: Amblycipitidae). Environmental as above. Oreoglanis majuscula: RGUMF128, 7, Biology of Fishes 101 (3): 459-467. 35-75 mm SL, Kameng River at Rupa, AP. Exo- SINHA, B. & TAMANG, L. 2014. Creteuchiloglanis aru na - stoma labiatum: RGUMF 439, 2, 53.8-76.1 mm chalensis, a new species of glyptosternine catfish SL. Tezu River at Tezu, Lohit district, AP. (Teleostei: Sisoridae) from Arunachal Pradesh, northeast- Parachiloglanis hodgarti: RGUMF 406, 3, 35-75 ern India. Ichthyological Research 62 (2): [1-8] 189-196. mm SL, Yomgo River at Menchuka, Upper Siang THONI, R. J. & GURUNG, D. B. 2018. Morphological and district, AP. molecular study of the torrent catfishes (Sisoridae: Glyp- tosterninae) of Bhutan including the description of five new species. Zootaxa 4476 (1): 40-68. ACKNOWLEDGEMENTS ZHOU, W., LI X. & THOMSON, A. W. 2011. A new genus Authors are grateful to the Department of of glyptosternine catfish (Siluriformes: Sisoridae) with Biotechnology, New Delhi for financial support descriptions of two new species from Yunnan, China. (File No.BT/PR16506/NER/95/210/2015 dated Copeia 2011 (2): 226-241.

aqua vol. 25 no. 1 - 25 January 2019 24