Badis chittagongis Kullander & Britz, 2002

Kullander, Sven, Norén, Michael, Rahman, Md. Mizanur & Mollah, Abdur Rob, 2019, Chameleonfishes in Bangladesh: hipshot taxonomy, sibling species, elusive species, and limits of species delimitation (Teleostei: Badidae), Zootaxa 4586 (2), pp. 301-337 : 315-319

Badis chittagongis Kullander & Britz, 2002

( Fig. 7 )

Material examined. All from Chittagong Division, Cox′s Bazar District: NRM 68179, 1 27.8 mm SL, NRM 67448, 1 , 29.7 mm SL; NRM 67449, 1 ; Maheshkhali Upazila : Maheshkhali Island, Khalmadia Chora, 5 km N of Maheshkhali Upazila, 21°35′2″N, 91°57′55″E; M.M. Rahman et al., 11 May 2015 (SRL-2015-015) .— NRM 67804, 1 , NRM 67972, 1 ; NRM 67973, 1 , SL; NRM 68203, 1 , 15.4 mm SL; Maheshkhali Island , small stream in Khalmadia Chora, 8 km north of Maheshkhali Upazila. 21°35′14″N 91°57′59″E; M.M Rahman et al., 11 May 2015 (SRL-2015-016) .—NRM 68121, 21,19.0– 33.6 mm; Maheshkhali Island , ravine about 7 km north of boat landing, 21°34′51″N, 91°57′47″E; M.M. Rahman, et al., 11 May 2015. (SRL-2015-017) .— NRM 67141, 1 , NRM 68040, 7 , 23.8.1– 37.8 mm SL; Gorakghata , Maheshkhali Island , Khaler Uttarkul, Barachora Stream, 21°30′51″N, 91°57′57″E; M.M. Rahman et al., 11 May 2015 (SRL-2015-018) .— NRM 66205, 7 , 24.7 – 41.7 mm SL mm SL; Cox′s Bazar Sadar, Barachora hillstreams about 6 km SE of Cox′s Bazar town, 21°23′46″N, 92°0′2″E; A.R. Mollah, 4 Apr 2014 ( ARM2014-001 ) .—NRM 67404 (T10613), 1, 29.6 mm SL; NRM 67405, 1 ; NRM 67406, 1 ; NRM 674071 ; NRM 67408, 1 ; NRM 67409, 1 ; NRM 67410, 1 ; NRM 67411, 1 ; NRM 67412, 1 ; NRM 68074, 52 , 16.3 – 43.1 mm SL; Barachora stream, 4 km south of Cox′s Bazar, 21°23′45″N, 92°0′13″E; M.M. Rahman et al., 8 May 2015 (SRL-2015-001) .— NRM 67212, 1 ; Teknaf , Sonarpara Bazar, Delpara stream, 21°16′12″N 92°3′28″E; M.M. Rahman, 9 May 2015 (SRL-2015-008) .— NRM 67237, 1 ; Kuikhali , small pool close to trail from Kudong Cave, 21°5′38″N, 92°10′5″E; M.M. Rahman et al., 9 May 2015 (SRL-2015-006) .— NRM 67342, 18 , 18.1 – 31.7 mm SL; NRM 67829, 1 ; NRM 67830, 1 ; NRM 67831, 1 , 28.7 mm SL; Kudung Cave in Teknaf Game Reserve , 21°5′32″N, 92°10′11″E; M.M Rahman, 9 May 2015 (SRL-2015-004) .— NRM 67374, 1 ; NRM 67375 1; NRM 68174, 6 , 14.5 – 33.4 mm SL; Teknaf , Godarpar Stream at Sonarpara Bazar, small stream to Bay of Bengal, 21°16′44″N 92°3′24″E; M.M. Rahman, 9 May 2015 (SRL-2015-007) .

Description, based on new material. Proportional measurements are given in Table 3 ; selected meristics in Tables 6–7. Moderately elongate, strongly compressed laterally. Predorsal contour straight or slightly curved, sloping at same angle as slightly curved prepelvic contour. Orbit situated in anterior half of head and at level of mid-axis of body. Jaws about equal anteriorly, lower jaw only slightly projecting before upper; maxilla reaching slightly posterior of vertical through anterior margin of orbit. Lower jaw articulation below middle of orbit. Simple strong opercular spine. Well-developed tooth-patches on parasphenoid, basibranchial 3, basihyal, palatine and vomer. Some females can be distinguished by bulging abdomen.

Scales in a lateral row 26 (7), 27 (12). Lateral-line scales 18/1 (1), 19/1 (1), 19/4 (1), 20/3 (1), 20/4 (1), 20/5 (1), 21/2 (1), 21/4 (2), 21/6 (1), 22/4 (5), 22/5 (2), 23/3 (2), 23/3 (2). Predorsal scales 11 (1), 12 (14), 13 (4), 14 (1). Circumpeduncular scale rows 16 (2), 17 (4), 18 (12), 19 (1). Scales between first dorsal fin-spine and upper lateral line 3, posteriorly 1½ scales between dorsal-fin base and upper lateral line; full-sized scales between first anal-fin spine and upper lateral line 7. Scale rows on cheek 4, on opercle 4, on preopercle 1, on interopercle 1. From about fifth dorsal-fin spine, dense layer of small rounded scales, 3–4 on each interradial space, covering spinous dorsal- fin base up to at most middle of fin height; on base of soft dorsal fin, 3–4 smaller scales in an interradial space. Anal fin from behind third spine to anterior soft rays with narrow layer of small rounded scales, 3–4 in each interradial space.

Dorsal-fin rays XVI.7½ (1), XVI.8½ (6), XVI.8½ (10), XVII.7½ (1), XVII.8½ (1), XVII.17.9½ (1) Soft analfin rays 6½ (10), 7½ (9). Soft dorsal and anal fins with rounded or subacuminate tip, reaching to middle, or ¼of caudal fin, or shorter. Caudal fin rounded. Pectoral-fin rays 11 (2), 12 (2), 13 (6). Pectoral fin rounded, not reaching posteriorly to tip of pelvic fin. Pelvic fin with point formed by second soft ray, reaching more than halfway to vent.

Ceratobranchial 1 gill-rakers 6 (3), 7 (4), 8 (10), 10 (1). Supraneurals 3 (4), vertebrae 14+13=27 (1), 14+14=28 (1), 15+13=28 (1), 16+13=29 (1).

Colour pattern. Ground colour beige. Postorbital stripe composed of black spots covering two or three scales in oblique row posterodorsally from orbit at about 1400h position. Dark grey or black suborbital and preorbital stripes. Tip of maxilla white. Top of head medially dark brown. Black spot covering exposed part of cleithrum. Indistinct narrow vertical stripe from base of first dorsal-fin spine, across gill cover. On sides five pairs of dark brown vertical bars, each formed by dark spots on scales; bars in each pair well separated, interbar spaces usually dark, contributing to broad vertical bar, but particularly two or three posterior pairs with pale interspaces. Large males with wide vertical bars, rarely tending to uniformly dark sides. Juveniles and young specimens, under 20 mm with distinct vertical bars. Dorsal fin black on basal half; vertical bars forming spots where terminating on base of dorsal fin. Dorsal-fin lappets with narrow white distal margin and narrow black submargin, rest of interradial membrane grey; soft fin pale greyish, semitransparent. Row of dark spots along middle of spinous dorsal fin frequently present, immediately distal to basal scale cover. Caudal-fin base usually covered by dark brown or black vertical bar, obscuring or obliterating caudal blotch; otherwise, a median dark brown caudal blotch, or dark blotches present at middle, and at dorsal and ventral margins of caudal-fin base.

Geographical distribution and habitats. Small streams on Maheshkhali Island and in small coastal streams draining to the Bay of Bengal from near Cox′s Bazar south to Teknaf Game Reserve ( Figs 8 ).

Remarks. The description of Badis chittagongis from Cox’s Bazar is provided to facilitate comparison with B. pallidus . It agrees with the description in Kullander & Britz (2002), with slight deviations in count frequencies, and is similar to other species of the B. badis group ( B. badis , B. kanabos , B. rhabdotus , B. pallidus ) in the absence of strong dark markings, and the presence of a common colour pattern of indistinct, narrow and irregular dark vertical stripes on the side, a dark midbasal blotch on the caudal-fin base, and a dark spot on the exposed cleithrum. It differs from B. badis and B. kanabos in a slightly elevated number of scales (26–29, usually 27 vs. 25–26, rarely 27), along the middle of the side, and from B. kanabos also in the absence of a dark blotch anteriorly on the dorsal fin. The type locality is a small stream in the town of Lama, in the Matamuhuri River drainage ( Kullander & Britz, 2002). Kullander & Britz (2002) also reported the species from the near Khagrachori in the Karnafuli River drainage, but these records should probably be referred to B. pallidus as newly collected specimens from the Karnafuli drainage were identified as B. pallidus based on the coi sequence (see below)

Two distinct haplogroups were obtained of specimens morphologically identified as B. chittagongis ; specimens from Cox′s Bazar and Maheshkhali Island, distinguished here as B. chittagongis , and specimens from the Karnafuli and Sangu River drainages, distinguished here as a distinct species, B. pallidus . No morphometric differences were recorded between the two haplogroups ( Tables 3–4 ), but specimens of the Cox′s Bazar- Maheshkhali Island haplogroup tend to be somewhat darker overall, and differ slightly in colour pattern and meristics (see below).

Figures

FIGURE 7. Badis chittagongis. A, adult male, NRM 68074, 40.8 mm SL; B, adult female, 35.0 mm SL; Both from Bangladesh: Barachora stream, 4 km south of Cox′s Bazar; C adult male, NRM 68040, 37.8 mm SL, from Bangladesh: Maheshkhali Island, Khaler Uttarkul.

FIGURE 8. Collecting site of Badis chittagongis on Maheshkhali Island, 7 km north of boat landing.