Review of the spiny eels of northeast India with description of Macrognathus dhanzei sp. nov. (Teleostei: Synbranchiformes: Mastacembelidae)

Abstract

Northeast India is one of important ichthyobiodiversity hot-spot area, mainly drained by four river drainages or basins viz., Brahmaputra, Barak-Meghna-Surma, Chindwin and Kaladan. Eight species viz., five species of spiny eels of Macrognathus and three species of Mastacembelus are reported from this region and shared 9.19% in the world. Macrognathus aculeatus of Dhanze et al. (2018) is erected as a new species, M. dhanzei due to lack of ocelli, 28-34 vertical transverse bars, XXIV-XXVII dorsal spines, 31-38 soft dorsal fin rays, i 15-18 pectoral fin rays, 30-41 soft anal fin rays, 10-12 caudal fin rays, dorsal spine fin base length 72.6-79.9%SL, preorbital or snout length 34.3-44.0% HL, head width 15.2-29.1%HL, upper jaw length 24.3-30.0% HL, absence of rostral plates and presence of 72 vertebrae respectively. Easiest key for the spiny eel of the genus Macrognathus in the northeast India is provided.