Channa royi (Teleostei: Channidae): a new species of snakehead from Andaman Islands, India

A new species of snakehead fish Channa royi sp. nov., has been described based on 21 specimens collected from the South, Middle and North Andaman Islands, India. It is distinguished from all its congeners by a greenish-grey dorsum, pale brown to black pectoral fin with 2-3 inconspicuous semicircular bands, a series of 7-9 obliquely-arranged, saddle-like, dark olive to grey oblique streaks on green background on upper half of the body, 42-45 pored lateral-line scales, 12-13 branched caudal rays, 6-7 pre-dorsal scales, 43 vertebrae, two rows of teeth on the lower jaw, an outer row of numerous minute slender, pointed teeth and single inner row of large uniform sized teeth without any large canine like teeth on the anterior fourth of the lower jaw. Phylogenetically C. royi sp. nov. is closely related to C. harcourtbutleri, with a genetic distance (K2-P) of 2.4-2.8%, but morphologically differs in having greater inter-orbital width, fewer pelvic-fin rays (5 vs. 5-7, mode 6); fewer caudal-fin rays (ii- i, 10-12, i-ii vs. ii, 15, ii); more pre-dorsal scales (6-7 vs. 4) and fewer mid row lateral-line scales (9-13 vs. 15-16). Though Channa royi sp. nov. is a part of C. gachua species-group, it differs from the topotypic C. gachua from Bengal with higher pair-wise sequence distance of 19.5-20.9%.