Myanmar Sea Bass

description

Description. See Table 1 for proportional measurements. Body compressed (body width 49.3 ‒ 50.4 % body depth), its depth 3.1 ‒ 3.5 times in SL, deepest at dorsal-fin origin. Dorsal profile concave in interorbital region, rising steeply (convex) thereafter to dorsal-fin origin. Head moderately acute, its length 2.8 times in SL. Eye oval, height less than width, eye diameter 7.5 ‒ 8.6 times in head length. Snout 4.7 ‒ 5.2 times in head length. Interorbital space 114 ‒ 122 % eye diameter. Mouth oblique, lower jaw projecting beyond upper one when closed. Maxilla deep, its depth 104 ‒ 120 % eye diameter, extending posterior to level of eye. Villiform teeth present on jaws, palatines, pterygoids and vomer. Tongue smooth. Three sharp, strong spines on inferior margin of preoperculum, first antrorse; a retrorse spine at angle of preoperculum. Preoperculum posterior margin with 26 ‒ 34 serrae. A sharp spine at angle of operculum. Seven branchiostegal rays. Inferior edge of infraorbitals 1 and 2 finely serrated. Nares level with middle of eye, separated from eye by distance less than diameter of posterior naris. Gill rakers 3 + 1 + 8 ‒ 9, densely denticulated on proximal side. Cleithrum and

Description of two new species of sea bass (Teleostei: Latidae: Lates) from Myanmar and Sri Lanka

diagnosis

Diagnosis. Lates uwisara is distinguished from L. calcarifer by possessing 7 (vs. 6) scales between the base of the third dorsal-fin spine and the lateral line; and having a lesser eye diameter (4.4 ‒ 4.7 % SL, n = 3; vs. 4.8 ‒ 6.9 % SL, n = 25). It differs from L. lakdiva by having a greater body depth (28.4 ‒ 34.5 % SL, vs. 26.6 ‒ 27.6 % SL), a longer dorsal-fin base (43.3 ‒ 45.0 % SL, vs. 41.1 ‒ 43.2 % SL), a lesser eye diameter (4.4 ‒ 4.7 % SL, vs. 5.5 ‒ 5.6 % SL), and by possessing 7 (vs. 5) rows of scales between the base of the third dorsal-fin spine and the lateral line. It is distinguished from L. japonicus by having the third anal-fin spine shorter (vs. longer) than the second; a shorter caudal peduncle (15.8 ‒ 17.6 % SL, vs. 18.2 ‒ 20.2 % SL) and a greater preanal distance (72.9 ‒ 75.6 % SL, vs. 67.5 ‒ 72.3 % SL).

Description of two new species of sea bass (Teleostei: Latidae: Lates) from Myanmar and Sri Lanka

discussion

Remarks. Ward et al. (2008) investigated CO 1 sequence divergence in Lates from Western Australia, Queensland, Singapore and Myanmar. While the former three populations were shown to be almost identical (0.5 % divergence), the Myanmar specimens showed a divergence of 9.5 %, sufficient to signify a distinct species (Page & Hughes 2010; Benziger et al. 2011). The type series of L. uwisara comprises the same specimens analysed by Ward et al. (2008). Interestingly, these authors also found a sample of Lates from French Polynesia to be identical to three of the Myanmar specimens. Lates does not occur naturally in French Polynesia where it has, however, been introduced for aquaculture (FAO 2011). While it is thus clear from Ward et al. (2008) that L. uwisara has already been used in aquaculture, it also raises a question over its type locality: is it indigenous to Myanmar waters, or might it have been introduced there, too? Data on three further Myanmarese specimens (ZSI FF 125, 177 mm SL, from Pegu [Bago]; ZSI FF 302, 141 mm SL, from Moulmein [Mawlamyaing]; and ZSI FF 410, 263 mm SL, from Akyab [Sittwe]) in the Francis Day collection at the ZSI (collected ca 1880), kindly provided by S.

Description of two new species of sea bass (Teleostei: Latidae: Lates) from Myanmar and Sri Lanka

etymology

Etymology. The species-name is a patronym honouring the Burmese patriot U Wisara; it is formed as a substantive in apposition. We suggest Myanmar Sea Bass as the common name of this species.

Description of two new species of sea bass (Teleostei: Latidae: Lates) from Myanmar and Sri Lanka