Channa rakhinica, Britz & Hui & Rüber, 2024

Britz, Ralf, Hui, Tan Heok & Rüber, Lukas, 2024, Four new species of Channa from Myanmar (Teleostei, Labyrinthici, Channidae), Raffles Bulletin of Zoology 72, pp. 1-25 : 3-9

Channa rakhinica , new species

( Figs. 2–5 )

Holotype. BMNH 2019.10 .16.190, 124.5 mm SL; Myanmar: Rakhine State, Kyeinthali township, Kyauk Tan village, South Stream , 18.0380°N 94.5072°E, coll. Britz et al., 1 December 2009.

Paratypes. BMNH 2019.10.16.191–193, 3 ex., 80.0– 92.5 mm SL; same information as holotype . MTD 40204 , 1 ex., 113.0 mm SL; same information as holotype . — BMNH 2019.10.16.276–282, 7 ex., 64.5–86.5 mm SL; Myanmar, Kyeinthali, coll. Tin Win et al., October 2008 . — BMNH 2022.6.23.1004–1006, 3 ex., 83.3–97.1 mm SL; Myanmar, Rakhine State, Kyeinthali township, Kyauk Tan village, North Stream , 18.0455°N 94.4942°E, coll. Britz et al., 1 December 2009 . — BMNH 2019.10 .16.259, 1 ex, 94.2 mm SL; Myanmar, Rakhine State, Kyeinthali township, Kyeinthali Chaung , coll. Tin Win et al., October 2008 . — BMNH 2019.10.16.269–275, 7 ex., 95.7–125.3 mm SL; Myanmar, Rakhine State, Kyeinthali township , Kyeinthali Chaung, coll. Tin Win et al., October 2008 . — BMNH 2019.10.16.261–264, 4 ex., 95.1–126.0mm SL; Myanmar, Rakhine State, Kyeinthali township , Kyeinthali Chaung, coll. Tin Win et al., 5 December 2004 . — BMNH 2007.8.17.1–10, 10 ex., 57.7–105,7 mm SL; Myanmar, Rakhine State, Ann township, Kazukaing villlage, remnant pools of Myaung Gyi Chaung , a tributary of Dalet Chaung , 19.9247°N 93.7933°E, coll. Britz et al., 5 April 2007 . — BMNH 2019.10.16.207–258, 48 ex., 42.0– 121.2 mm SL; Myanmar, Rakhine State, Ann township, Kazukaing villlage, remnant pools of Myaung Gyi Chaung , a tributary of Dalet Chaung , 19.9247°N 93.7933°E, coll. Britz et al., 5 April 2007 . — MTD 40205 , 5 ex., 55.4–110.9 mm SL; Myanmar, Rakhine State, Ann township, Kazukaing villlage, remnant pools of Myaung Gyi Chaung , a tributary of Dalet Chaung , 19.9247°N 93.7933°E, coll. Britz et al., 5 April 2007 . — MTD 40206, 121.8 mm SL; Myanmar, Rakhine State, Kyauktaw township, Sinkae villlage, remnant pools of tributary stream of Laymyo (Lemro) River , 20.7554°N 93.2713°E, coll. Britz et al., 4 April 2007 . — BMNH 2007.8.17.12–20, 9 ex., 56.5–114.7 mm SL; Myanmar, Rakhine State, Kyauktaw township, Sinkae villlage, remnant pools of tributary stream of Laymyo (Lemro) River , 20.7554°N 93.2713°E, coll. Britz et al., 4 April 2007 .

Diagnosis. A member of the Gachua group readily distinguished from other Myanmar members by its colour pattern in life including reddish cheek, series of up to 5 semicircular concentric maroon pectoral bands wider than interbands, series of 6–7 saddle-like blotches, orange subdistal and white distal rim on dorsal- and caudal fins (vs. different colour pattern). It is further distinguished from C. stewartii by fewer dorsal-fin rays (34–38 vs. 39–41), and generally fewer anal-fin rays (23–25, rarely 22 or 26 vs. 26–27) and from C. burmanica by presence of pelvic fins (vs. absence). It also differs substantially from all Myanmar Gachua group snakeheads by a genetic distance of 12.9–18.5% in the COI gene.

Description. See Figs. 2–3 , 5 for general appearance and Table 2 for morphometric information and Table 6 for select meristic characters. Body elongate, round in cross section anteriorly, laterally compressed at caudal peduncle, body depth 5.6–6.3 times in SL. Head large, length 3.2–3.5 times in SL. Head widest halfway between posterior margin of eye and that of opercle. Mouth large, maxilla extending posteriorly beyond jaw angle, lips fleshy. Premaxilla with multiple rows of small sharp, pointed teeth ( Fig. 4a ). Dentary also with several series of small teeth anteriorly, a single series of small teeth along most of the lateral margin and an internal series of larger canines ( Fig. 4b ). Vomer with a few very large teeth in the middle and smaller teeth at lateral corner ( Fig. 4a ). Palatine with external series of smaller teeth and an internal row of up to 7 much larger canines ( Fig. 4a ). Parasphenoid posteriorly with several medium sized teeth ( Fig. 4d ). Hypobranchial 3 with a patch of tiny teeth ( Fig. 4c ). Ceratobranchial 5 with series of large teeth with anteriorly directed tips along posterior and medial margin and smaller teeth in middle and along anterior margin ( Fig. 4c ). Pharyngobranchial 2 elongate with several series of tiny teeth ( Fig. 4d ). Pharyngobranchial 3 with prominent teeth with recurved tips ( Fig. 4d ). Upper pharyngeal toothplate 4 with larger recurved teeth anteromedially and smaller teeth posterolaterally ( Fig. 4d ).

Pectoral-fin rays 14*–15. Dorsal-fin rays 34(4), 35(11), 36*(46), 37(23), 38(5). Anal-fin rays 22(2), 23*(20), 24(46), 25(18), 26(3). Caudal fin with 6(55) or 7*(39) + 7(17), 8*(75) or 9 (1) principal rays and 2(30), 3*(57) or 4(7) dorsal and 2 (53), 3*(31) or 4 (4) ventral procurrent rays. 44(9), 45*(25), 46(50) or 47(12) vertebrae with 38(2), 39(16), 40*(38), 41(38) 42(1) abdominal and 4(3), 5*(51) or 6 (44) caudal vertebrae.

Predorsal scales 7–9. Lateral line with 45–47 scales extending from shoulder girdle in horizontal line, but dropping one scale row at scale 13–17, then continuing horizontally to end of caudal peduncle. Scales above lateral line 3.5 and below 6.5–7.5 at level of anal-fin origin. Postorbital scales 7 or 8. Circumpeduncular scales 28, with 8 larger scales on each side and 6 smaller to tiny scales along dorsal and ventral midline. Prepelvic scales 10–13. Single scale on ventral aspect of anguloarticular.

Colouration in preservative. See Figs. 2–3 . Body and fins dark maroon, slightly lighter ventrally. Dorsal, anal, and caudal fins with narrow white rim. Pectoral fins with dark brown base and alternating dark wide and light narrow bands, bands regularly arranged in semiconcentric fashion in specimens from the south of distribution range, but in more northern populations dark bands wider and light bands sometimes incomplete, not reaching distal margin of fin.

Colouration in life. See Fig. 5 . Colour of body a light maroon with light grey marbling especially in ventral area, light grey ventrally on jaw, gular area and abdominal preanal area and a series of 6–7 darker brown saddle-like blotches

RAFFLES BULLETIN OF ZOOLOGY 2024

running from dorsal-fin base anteroventrally to upper third of side of body. Sides of head especially opercular region often with reddish brown cheek blotch. Dorsal fin with dark oblique markings separated by light oblique lines, sometimes forming black blotch in posteriormost area. Dorsal and caudal fins with submarginal orange rim and narrow white distal margin. Caudal fin with irregular semiconcentric dark narrow bands separated by lighter areas. Anal fin with dark brown subdistal rim and white distal margin. Pectoral fins with series of semicircular concentric maroon bands alternating with narrower cream bands. Pelvic fins light grey, like ventral abdomen.

Distribution and habitat. The new species was collected from small mountain streams near Kyeinthali in the southern Rakhine Yoma ( Fig. 6 ) and from small remnant puddles beneath large boulders in the otherwise dry bed of a small tributary stream of Dalet Chaung in the middle Rakhine Yoma, and Laymyo River in the northern Rakhine Yoma, respectively ( Fig. 7 ).

Etymology. The species name is derived from the name of the area where it occurs, the Rakhine Yoma in western Myanmar, an adjective.

Remarks. This species has been traded as an ornamental fish since at least 2012 under the name “ Channa sp. mimetic pulchra” and has been referred to as Channa sp. Rakhine Yoma in Conte-Grand et al. (2017) and Rüber et al. (2020). Aquarium reports suggest that this is a mouthbrooding species.

Figures

Fig. 2. Channa rakhinica, BMNH 2019.10.16.190, 124.5 mm SL, holotype, in dorsal (top), lateral (middle), and ventral (bottom) view; Myanmar: Rakhine State, South Stream.

Fig. 3. Channa rakhinica, paratypes in lateral view, BMNH 2019.10.16.207-258, 111.7 mm, Myanmar, Rakhine State, Dalet Chaung (top), MTD 40206, 121.8 mm SL, Myanmar, Rakhine State, Laymyo Chaung (bottom).

Fig. 4. Channa rakhinica, MTD 40204, paratype, 113.0 mm SL. Volume rendered 3D models illustrating dentition on premaxilla, vomer and palatine, in ventral view (a), lower jaw (b) in dorsal view, ventral branchial arches (c) in dorsal view, and upper pharyngeal jaws and parasphenoid patch (d) in ventral view. Note presence of caniniform teeth on palatine and dentary. Abbreviations: cb 5, ceratobranchial 5; de, dentary; hb3, hypobranchial 3; pal, palatine; pb2, pharyngobranchial; pb3, pharyngobranchial 3; pmx, premaxilla; ps, parasphenoid up4, upper pharyngeal toothplate 4. Scale bars 1 cm.

Fig. 5. Channa rakhinica, paratypes, examples of colouration in life, BMNH 2022.6.23.1004–1006 (top and middle), not measured, ca. 90 mm SL; BMNH 2019.10.16.269–275 (bottom), not measured, ca. 110 mm SL.

Fig. 6. South stream near Kyeinthali, type locality of Channa rakhinica.

Fig. 7. Remnant pools under large boulders in dry stream beds, habitat from which Channa rakhinica paratypes were collected at Seik Chaung, a small tributary of Laymyo river and Myaung Gyi Chaung, a tributary of Dalet Chaung.