Laubuka tenella

biology_ecology

Habitat and biology The stream in which Laubuka tenella was found had an average water depth 0.9 m, with steady flow. The ground is sandy and the water is clean. Coexisting species include Mystus gulio, Pethia conchonius, Pethia stoliczkana, and Glossogobius giuris.

A review of genus Laubuka (Cypriniformes: Danionidae) in Myanmar with description of two new species

description

Description Measurements and counts are shown in Table 5 and Figure 8 for general appearance. Body elongate, strongly compressed laterally. Predorsal contour gradually rising, the highest point at base of dorsal-fin origin. Abdomen rounded. Eyes large, lateral, place in middle of head length. Snout short. Mouth terminal. Lower jaw with minute papillae. Tubercles absent. Barbels absent. Scales cycloid, thin, and transparent. Dorsal fin origin at anterior two-thirds of standard length, length of rays gradually decreased. Dorsal-fin rays ii. 8 ½ (10). Anal-fin base longer than dorsal-fin base, posterior rays gradually shorter. Anal-fin rays iii, 16 ½ (2), 17 ½ (2), 18 ½ (6). Pectoral fin long, falcate, unbranched ray longest or unbranched ray and first branched ray equally long, almost reaching end of pelvic fin. Pectoral-fin rays i. 10 (7) or 11 (3). Pelvic fin short, not reaching anus. Pelvic-fin rays i. 6 (10). Caudal peduncle slender. Caudal fin forked. Caudal fin lobes almost subequal. Lateral line complete, with 29 – 32 + 1 scales. Predorsal scales 16 (3), 17 (2), 18 (5), prepelvic and preanal region scaled. Circumpeduncular scales 12 (10).

A review of genus Laubuka (Cypriniformes: Danionidae) in Myanmar with description of two new species

diagnosis

Diagnosis Laubuka tenella is distinguished by the combination of the following characters: Presence of a dark stripe along middle of posterior third of side, anteriorly replaced by short vertical bars, abdomen white, body elongate, strongly compressed laterally, mouth terminal, pectoral fin long and falcate, almost reaching end of pelvic-fin rays, pelvic fin short, dorsal-fin rays ii, 8 ½, predorsal scales 16 – 18, lateral-line scales 29 – 32, fins hyaline.

A review of genus Laubuka (Cypriniformes: Danionidae) in Myanmar with description of two new species

discussion

Comparisons The interspecific variation in L. tenella is 0.00 and sequence similarity is 99.7 between Myanmar and Bangladesh samples. Based on the original description of Kullander et al. (2018), the preserved color pattern of L. tenella reported here is different from Rakhine samples, but share the same proportional measurements and counts. The published photograph (Kullander et al. 2018; fig. 1) of the type, shows 6 distinct anterior vertical bars (vs. 2 indistinct vertical bars or absent). Laubuka tenella is distinguished from Sri Lanka Laubuka species by having 16 – 18 predorsal scales (vs. 18 – 21 in L. lankensis, L. insularis, L. ruhuna, and L. hema); 29 – 32 lateral-line scales (vs. 33 – 35 in L. hema, 34 – 37 in L. lankensis, and 34 – 36 L. insularis); a shorter pelvic-fin length, of 14.9 – 20.8 % SL (vs. 25.4 – 32.0 % SL in L. lankensis, L. insularis, and L. hema) and the presence of an entire, narrow lateral band on the posterior third of the body (vs. a series of blotches along the side in L. ruhuna and L. varuna). It is further distinguished from Indian Laubuka species by the presence of a dark stripe along the posterior third of the side, anteriorly replaced by short v

A review of genus Laubuka (Cypriniformes: Danionidae) in Myanmar with description of two new species