https://doi.org/10.11646/zootaxa.4695.2.4 http://zoobank.org/urn:lsid:zoobank.org:pub:66E5133E-4BB0-438E-9A33-559EDDB8AA29 148 Accepted by P. Ciccotto: 14 Oct. 2019; published: 7 Nov. 2019 Article ZOOTAXA ISSN 1175-5326 (print edition) ISSN 1175-5334 (online edition) Zootaxa 4695 (2): 148–158 https://www.mapress.com/j/zt/ Copyright © 2019 Magnolia Press A new species of rheophilic cyprinid fish (Teleostei: Cyprinidae) from the Brahmaputra Basin, northeast India BUNGDON SHANGNINGAM 1 , LAISHRAM KOSYGIN 2 & BIKRAMJIT SINHA 3 1,2 Zoological Survey of India, Freshwater Fish Section, 27 J.L. Nehru Road, Kolkata—700016, India. 3 Zoological Survey of India, Arunachal Pradesh Regional Centre, Senki Valley, Itanagar, Arunachal Pradesh 791113, India. E-mail: bdshangningam@gmail.com 1 ;lkzsi5@yahoo.com 2 Abstract A new species of the genus Garra is described from the Ranga River of the Brahmaputra basin, Arunachal Pradesh, northeastern India. Garra magnacavus, new species, differs from its congeners in having an incipient proboscis with a transverse lobe, 15−19 rounded large pits on the snout, weakly developed non-fleshy central callous pad, and an elongate body with 42 lateral-line and 14−16 predorsal scales. Key words: Garra, new species, Ranga River, Arunachal Pradesh Introduction Northeast India possesses ideal habitats for the labeonine genus Garra Hamilton 1822. Members of the genus are elongate, small- to medium-sized, and inhabit fast-flowing rivers and oxygen-rich mountain streams by maintaining themselves against swift currents. The genus Garra is diagnosed from the labeonine genera in having the width of the crescentic anteromedian fold of the lower lip equal to or wider than the callous pad, the lateral end of the antero- median fold on each side reaching the anterolateral lobe of the mental adhesive disc, and three rows of pharyngeal teeth (Nebeshwar & Vishwanath 2017). At present, Northeast India is home to 40 valid species of the genus Garra distributed in the mountainous rivers and streams of the Brahmaputra, Barak, Kaladan, Karnaphuli and Chindwin drainages. Nineteen species of the ge- nus are considered valid in the Brahmaputra drainage viz., G. annandalei Hora 1921, G. arunachalensis Nebeshwar & Vishwanath 2013, G. arupi Nebeshwar et al. 2009, G. birostris Nebeshwar & Vishwanath 2013, G. biloborostris Roni & Vishwanath 2017, G. bimaculacauda Thoni et al. 2016, G. clavirostris Roni et al. 2017, G. gotyla (Gray 1830), G. jenkinsoniana Hora 1921, G. kalpangi Nebeshwar et al. 2011, G. kempi Hora 1921, G. lamta (Hamilton 1822), G. lissorhynchus (McClelland 1842), G. magnidiscus Tamang 2013, G. nasuta (McClelland 1838), G. paras- tenorhynchus Thoni et al. 2016, G. quadratirostris Nebeshwar & Vishwanath 2013, G. rupecula (McClelland 1839) and G. tamangi Gurumayum & Kosygin 2016. During an ichthyological exploration in March 2013 in the Ranga River, a tributary of the Brahmaputra Basin in Arunachal Pradesh, Northeast India, an unnamed species of Garra was collected. This species is herein described as Garra magnacavus. Material and methods The specimens were fixed in 10% formalin and then preserved in 70% ethanol. Measurements were made point to point with digital callipers on the left side of the specimen whenever possible. Counts, measurements and terminol- ogy follow Nebeshwar & Vishwanath (2013). Lateral-line scales are counted from the anteriormost pored scale in contact with the shoulder girdle to the posteriormost pored scale on the caudal fin. Transverse scale rows above