Wednesday, January 2, 2019

[Ichthyology • 2018] Channa royi • A New Species of Snakehead (Teleostei: Channidae) from Andaman Islands, India


Channa royi  Praveenraj & Knight

in Praveenraj, Knight, Kiruba-Sankar, et al., 2018. 
Andaman Emerald Snakehead  ||  DOI: 10.21077/ijf.2018.65.4.72827-01 

ABSTRACT
 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%.

Keywords: Andaman Islands, Channa gachua, Channa limbata, Channa royi sp. nov., Channidae, Snakeheads


Channa royi sp. nov. (a) Adult, 190.5 mm SL, showing black pectoral fin, uncatalogued,
 (b) Adult, 165.1 mm, showing pale grey pectoral fin, uncatalogued.
(both maintained in aquarium) (Photos: J. Praveenraj)

Channa royi sp. nov. (a). holotype prior to preservation (ZSI/ANRC-12467),
 (b). Juvenile specimen, uncatalogued, 44.6 mm SL.
 (Photos:  J. D. M. Knight)

Channa royi, sp. nov. Praveenraj & Knight
Common name: Andaman Emerald Snakehead 

Diagnosis: Channa royi sp. nov. is distinguished from all other species of the genus Channa belonging to the Channa gachua species-group by a combination of following characters: unique greenish-grey dorsum; upper half of body with a series of 7-9 obliquely-arranged, saddle-like, dark olive to grey oblique streaks on green background; throat with marbled pattern; 34-38 dorsal-fin rays; 22-25 anal-fin rays; 42-45 pored scales on body; 1-3 scales on caudal fin base; 3½ scales above lateral line and 6½ scales below lateral line; 6-7 pre-dorsal scales; 43 vertebrae; two rows of teeth on the lower jaw, single outer row of numerous minute slender pointed teeth and single inner row of enlarged uniform teeth without any large canine like teeth on anterior-fourth of the lower jaw; two rows of teeth on palatine; outer row with numerous minute sharp slender teeth and inner row with 4 to 6 large canine like teeth and pectoral fins pale brown to black in adults with 2-3 pale grey to black inconspicuous semicircular bands.
....

Etymology: The species is named after Dr. S. Dam Roy, in appreciation for his immense encouragement and support for the exploration of the freshwater fishes of Andaman and Nicobar Islands. The species name is formed as a noun in the masculine genitive singular. The common name ‘Andaman emerald snakehead’ is given considering its unique greenish dorsum. 

Distribution: Channa royi sp. nov. is currently known only from South, Middle and North Andaman Islands, India and is abundant in ditches, ponds and hill streams of the sampled locations. The holotype was collected from clear, slow flowing water with cobble substrate without much aquatic vegetation.

J. Praveenraj, J. D. M. Knight, R. Kiruba-Sankar, Beni Halalludin, J. J. A. Raymond and V. R. Thakur. 2018. Channa royi (Teleostei: Channidae): A New Species of Snakehead from Andaman Islands, India. Indian J. Fish. 65(4); 1-14.  DOI: 10.21077/ijf.2018.65.4.72827-01