Badis rhabdotus

description

Description. Based on Bangladeshi specimens. Proportional measurements are given in Table 5; 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, or steeper. Orbit situated in anterior half of head and level of midaxis 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. Well-developed tooth-patches on parasphenoid, basibranchial 3, basihyal, palatine and vomer. Dentary pores 3; anguloarticular pores 2; preopercular pores 7; nasal pores 2; supraorbital pores 3; extrascapular pores 2; supracleithral pores 2; posttemporal pores 2; coronalis pore; lachrymal pores 3; a row of free neuromasts across gap between lachrymal and anteriormost infraorbital; infraorbital pores 4. Scales in lateral row 27 (1), 28 (5). Lateral-line scales 19 / 4, 21 / 5, 22 / 6, 23 / 6, 24 / 5, 25 / 5 (one of each). Predorsal scales 11 (2), 12 (3), 14 (1). Circumpeduncular scale rows 18 (6). Scales between first

Chameleonfishes in Bangladesh: hipshot taxonomy, sibling species, elusive species, and limits of species delimitation (Teleostei: Badidae)

diagnosis

Diagnosis. Similar to B. badis, B. chittagongis, B. ferrarisi, B. kanabos, B. khwae, B. pallidus, B. ruber, B. siamensis, B. soraya, tuivaiei, and different from all other species of Badis in the presence of a dark blotch on the exposed cleithrum. Distinguished from B. khwae, B. ruber, and B. siamensis, in the absence of dark blotch dorsolaterally on the caudal peduncle. Distinguished from B. ferrarisi by the absence of short black bars along the middle of the side, and absence of a dark blotch on the gill cover. Distinguished from B. tuivaiei in the absence of a black blotch anteriorly on the dorsal fin, curved vs. straight vertical bars, and lower meristic values (28 – 29 vertebrae vs. 30 – 31; lateral scale row 27 – 29 vs. 26 – 32, modally 30; dorsal-fin rays XVI. 8 ½ or XVII. 7 ½ – 8 ½ vs. XVI. 9 - 10, XVII. 8, XVIII. 8 and modally XVIII. 9); from B. kanabos by the absence of black spot anteriorly on the dorsal fin, and from B. Badis by narrower interorbital space (4.8 – 5.5 % SL vs. 6.5 – 8.3 %, and more slender body (25.7 – 32.0 % SL vs. 30.7 – 38.9 %; not corrected for allometry). Similar only to Badis soraya in the presence of intense black narrow vertical bars on the sides

Chameleonfishes in Bangladesh: hipshot taxonomy, sibling species, elusive species, and limits of species delimitation (Teleostei: Badidae)

etymology

Etymology. Named rhabdotus, from the Greek ῥαβδωτóς, meaning striped, with reference to the prominent vertical bars characterizing this species. An adjective with alternative endings, - a, - um. Geographical distribution and habitat. In Bangladesh, specimens were sampled from a shallow sandy beach in a heavily converted area on the right bank of the Pyain River at Jaflong (Figs 3, 12). The site had some aquatic vegetation, but was otherwise bare. Seining in the main river, with a rocky bottom and current, did not yield any specimens of Badis. The sampling was made at the extreme low water season and may not have been characteristic of the biotope of the species. Georeferenced GenBank sequences (Fig. 1) show that B. rhabdotus has a wide distribution in the Meghna River basin, including the lower Barak River, tributaries in southern Meghalaya, distant Karnafuli headwaters, and possibly the Madopkundo Falls in Bangladesh.

Chameleonfishes in Bangladesh: hipshot taxonomy, sibling species, elusive species, and limits of species delimitation (Teleostei: Badidae)

materials_examined

Holotype. DU 9035, male, 46.9 mm SL; Bangladesh, Sylhet Division: Sylhet District: Meghna River drainage, Pyain River at Jaflong, 25 ° 11 ′ 4 ″ N 92 ° 0 ′ 59 ″ E. M. M Rahman et al., 24 March, 2016. Paratypes. DU 9036, 1, 34.6 mm SL; DU 9037 [ex NRM 69035 (11525], 1, 27.5 mm SL; NRM 68599, 4, 37.2. – 39.6 mm SL; NRM 69034, 1, 39.7 mm SL; collected with the holotype. NRM 51432, 1, 51.2 mm SL; NRM 70335, 2, 37.5 – 38.4 mm SL; India: Meghalaya: Wanapha River at Ummulong; H. Bleher, Sep 2009.

Chameleonfishes in Bangladesh: hipshot taxonomy, sibling species, elusive species, and limits of species delimitation (Teleostei: Badidae)