Journal of Research in Biology ISSN No: Print: 2231 –6280; Online: 2231- 6299 An International Scientific Research Journal Original Research Macrognathus siangensis, a new spiny eel from Brahmaputra basin, Arunachal Pradesh, Northeast India (Teleostei: Synbranchiformes) Authors: ABSTRACT: Arunkumar L Macrognathus siangensis, new species, from the Siang River, Brahmaputra drainage, northeast India, is distinguished from all other congeners by the following combination of characters: lack of rostral tooth plates, dorsal-fin spines 15-19, dark Institution: spots like imperfect ocelli along the base of dorsal soft branched fin rays 7-11, dark Department of Zoology, blotches at the mid-lateral sides of body 22-27, dorsal fin rays with two rows of Mayai Lambi College, parallel greyish streaks, caudal fin rays with 4-6 striated greyish streaks and body Yumnam Huidrom – 09, Manipur. width 59.0-67.4% of its depth. A key to Macrognathus species of northeast India including the newly described one is provided. Corresponding author: Keywords: Arunkumar L Macrognathus siangensis sp.nov., Siang river, Mastacembelid diversity, Northeast India. Email Id: Article Citation: Arunkumar L Macrognathus siangensis, a new spiny eel from Brahmaputra basin, Arunachal Journal of Research in Biology in of Research Journal Pradesh, Northeast India (Teleostei: Synbranchiformes) Journal of Research in Biology (2016) 6(3): 2003-2012 Dates: Received: 18 Jan 2016 Accepted: 26 Feb 2016 Published: 09 April 2016 Web Address: This article is governed by the Creative Commons Attribution License (http://creativecommons.org/ http://jresearchbiology.com/ licenses/by/4.0), which gives permission for unrestricted use, non-commercial, distribution and documents/RA0576.pdf reproduction in all medium, provided the original work is properly cited. 2003-2012 | JRB | 2016 | Vol 6 | No 3 Journal of Research in Biology An International Scientific Research Journal www.jresearchbiology.com Arunkumar, 2016 INTRODUCTION 2007), Vishwanath et al. (2007), and Yazdani (1985, Fish of the genus Macrognathus Lacepede are 1990) mainly reported about the ichthyofaunal distributed throughout the tropical Asia (Taki, 1975), distribution from northeast India. Presently, seven most of the Indian subcontinent and continental portions species of Macrognathus viz., M. albus (Plamoottil and of Southeast Asia (Roberts, 1980) and restricted to the Abraham, 2014b), M. aral (Bloch and Schneider, 1801), freshwaters of Africa and Asia (Roberts, 1986). This M. fasciatus (Plamoottil and Abraham, 2014a), mastacembelid fishes come under the order Perciformes M. guentheri (Day, 1889), M. lineatomaculatus (Britz, (Menon, 1974; Jayaram, 1981; Talwar and Jhingran, 2010); M. morehensis Arunkumar and Singh, 2000 and 1991; Yang and Zhou, 2011), Mastacembeliformes M. pancalus Hamilton-Buchanan, 1822, and three (Sen, 1985; Yazdani, 1990) and Synbranchiformes species of Mastacembelus viz., M. alboguttatus (Travers, 1984a,b; Jayaram, 1999; Khachonpisitsak Boulenger, 1893 M. armatus (Lacepede, 1800) and et al., 2008; Britz, 2009, 2010; Vreven, 2005b and M. malabaricus Jerdon, 1849 had been reported from Vreven and Stiassny, 2009) respectively. Sufi (1956), Indian waters already (Arunkumar and Singh, 1998 and Roberts (1980, 1986) and Vreven (2005b) revised the 2000; Britz, 2009; Jayaram, 1999; Plamoottil and mastacembelid fishes of Asian and African continents Abraham, 2013 and 2014a, b). respectively. Arunkumar and Singh (1998), Britz (2009 During an ichthyological survey (the 15th and 2010), Kottelat and Widjanarti (2005), Pethiyagoda December 2008) in East Siang district, Arunachal et al. (2008), Roberts (1980 and 1986), and Plamoottil Pradesh the author collected five specimens of the genus and Abraham (2013 and 2014, a,b) reported and Macrognathus from Siang River at Pasight. On detailed described new mastacembelid fishes of the genus study, the specimens were found to be distinct from all Macrognathus. As many as 24 species of Macrognathus known species. The species described here is were currently recorded (www.fishbase se/identification/ Macrognathus siangensis sp nov. species, downloaded on 05/11/2015). Britz, (2010) reported that 11 species of Macrognathus M. aureus MATERIALS AND METHODS from upper Ayeyarwaddy river drainage, Myanmar were Standard practices of Talwar and Jhingran distinguished and described. The systematic position of (1991), Jayaram (1999), Arunkumar and Singh (2000), Macrognathus caudiocellatus was reviewed and Britz (2009 and 2010), and Plamoottil and Abraham retransferred to Mastacembelus (Britz, 2009). Later (2014a, b) were followed while taking meristic and Macrognathus taeniagaster was synonymised to morphometric measurements. Measurements of Head M. semiocellatus (Vidhayanon, 2012). Length (HL) and body parts are expressed as proportions Northeast India is an important part of the Indo- of Standard Length (SL) and the subunits of head as Myanmar (Indo-Burma) biodiversity hot spot, one of the proportions of head length. The specimens were 34 global biodiversity hotspots. It is drained by the three deposited in the Manipur University Central Museum river systems viz., the Brahmaputra, the Chindwin and (MUCM), Canchipur. Registration numbers are given the Kaladan. below. Various worker viz., Arunkumar and Singh (1998, 2000), Bagra and Das (2010), Bagra et al. (2009), RESULT Hora (1921), Kar and Sen (2007), Nath and Dey (2000), Macrognathus siangensis sp. nov. (Figure. 1.) Sen (1985), Tamang et al. (2007), Vishwanath (2002, Common name: Arunachal’s Spiny Eel. 2004 Journal of Research in Biology (2016) 6(3):2003-2012 Arunkumar, 2016 Local name: Bami (by Adi people of Arunachal ventral side, more or less same as the interorbital Pradesh, India). distance. Scales are minute. Lateral line distinct and lies Manipuri name: Nagril macha/Chinglak ngaril one by third above the body depth. Spinous dorsal-fin is Holotype originating far behind the end of the pectoral fin. Anus is 43/NH/MUM 115.2 mm SL; Siang river at nearer to the base of caudal fin than to the snout. Anal Pasighat, East Siang district, Brahmaputra river drainage/ fin spines are covered and concealed by thick skin, basin, Arunachal Pradesh, India, 28º05'17" N and second spine longest. Caudal-fin rounded, distinctly 95º19'54" E; about 150m above mean sea level, 15.xii. separate from the dorsal and the anal fins. Proportional 2008, Coll. G.S. Sharma. measurements are given in Table 1. Paratypes Colour 4 specimens, 97-120.9mm SL; data same as for Dorsal dark grey, ventral yellowish pale white. A holotype. series of 7-11 dark spots like imperfect ocelli are present Diagnosis at the base of dorsal soft branched fin rays, 22-27 oblique A Macrognathus with the absence of rostral transverse bars on the lateral sides of the body, a tooth plates, dorsal fin spines 15-19, dark spots like longitudinally light greyish or light yellowish band from imperfect ocelli at the base of dorsal soft branched fin the posterior end of the eye upto the origin of branched rays 7-11, oblique transverse bars on the lateral sides of dorsal soft fin rays which lies above the lateral line and body 22-27, dark blotches on the lateral sides which distinct at the posterior end, blotches along dorsal-fin and increases their sizes from anterior to posterior ends mid -lateral blotches are only separated from posterior 22-27, dorsal fin rays with two longitudinal streak rows, eye upto the origin of dorsal soft branched fin rays and caudal fin rays with 4-6 fine striated streaks, body width joined upto the origin of caudal fin, 4-6 fine transversely 59.0-67.4% of its depth, head length at occiput and striated dark greyish streaks on caudal fin rays. Two predorsal length at dorsal spine origin 10.0-15.1% and parallel longitudinal streak rows of greyish bands on 34.3-39.0% of standard length respectively. dorsal and anal branched soft fin rays which are at the Description distinct posterior end. Pectoral fin is clear. Br. 3-5; D. 15-19/42-53; P. 22; A. 3/32-51; Etymology C. 13-14. General body shape and appearance is shown The species is named after the Siang River, in the Figure. 1. Body-eel like, occiput to the origin of Arunachal Pradesh, type locality of the species. dorsal fin spine subcylindrical and then laterally Distribution and Habitat compressed to the posterior end. Preorbital and Presently known only from the Siang River at preopercular spines are absent. Occipital region of head Pasighat, East Siang district, Arunachal Pradesh, scaleless but otherwise head including operculum and Brahmaputra river drainage, India. The fish inhabits the cheeks are covered with minute scales. Head long with pebbly bottom with sandy beds of swift, moderate and median fleshy rostral tentacles projecting from the upper turbid running water.. The following is a list of jaw. Mouth is found to be inferior and narrow. Lip is ichthyofaunal species collected syntopically with this fleshy. Gill membrane is connected to the isthmus. new species: Cyprinidae: Raiamas bola, Cabdio morar, Operculum opening is large ventrally but extending Amblypharyngodon mola, Cobitidae: dorsally only to the level of horizontal through upper Lepidocephalichthys guntea, Siluridae: Ompok pabo, third of pectoral fin base. Eyes not visible from the Schilbeidae: Clupisoma garua, Eutropiichthys vacha, Journal of Research in Biology (2016) 6(3):2003-2012 2005 Arunkumar, 2016 Key to Macrognathus species of the inland water bodies of India Rostral tooth-plates present 2 Rostral tooth-plates absent 11 Presence