Description of two new species of sea bass (Teleostei: Latidae: Lates) from Myanmar and Sri Lanka
Author
Pethiyagoda, Rohan
Author
Gill, Anthony C.
text
Zootaxa
2012
3314
1
16
journal article
10.5281/zenodo.281081
2975b12f-dea7-440e-acf2-5caf332508ef
1175-5326
281081
Lates lakdiva
,
new species
(
Fig. 2
)
Material examined:
holotype
, AMS I.37516-001,
220 mm
SL, St John’s Fish Market, Colombo,
Sri Lanka
, 1994;
paratypes
, AMS I. 37516-001,
2, 239 mm
SL and
256 mm
SL, same data as
holotype
.
Diagnosis.
Lates lakdiva
is distinguished from
L. calcarifer
by its lesser body depth (26.6‒27.6% SL, vs. 28.9‒34.6% SL); possessing 5 (vs. 6) rows of scales between the base of the third dorsal-fin spine and lateral line; 31‒34 (vs. 16‒26) serrae on the posterior edge of the preoperculum; and having the third dorsal-fin spine 3.0‒3.5 (vs. 2.1‒2.8) times the length of the second. It differs from
L. japonicus
by having the third anal-fin spine longer (vs. shorter) than the second; and possessing 5 (vs. 7) rows of scales between the base of the third dorsal-fin spine and the lateral line, a lesser body depth (26.6‒27.6% SL, vs. 30.3‒33.7% SL), and 47‒52 (vs. 58‒63) lateral-line scales.
Lates lakdiva
differs from
L. uwisara
by having a greater eye diameter (5.5‒5.6% SL, vs. 4.4‒4.7% SL), a lesser body depth (26.6‒27.6% SL, vs. 28.4‒34.5% SL), a shorter dorsal-fin base (41.1‒43.2% SL, vs. 43.3‒45.0% SL), and by possessing 5 (vs. 7) rows of scales between the base of the third dorsal-fin spine and lateral line.
FIGURE 2.
Lates lakdiva
, holotype, AMS I.37516-001, 220 mm SL.
Description.
See
Table 1
for proportional measurements. Body compressed (body width 43.6‒45.7% body depth), its depth 2.9‒3.8 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 6.4‒6.6 times in head length. Snout 5.3‒5.4 times in head length. Interorbital space 90.6‒95.2% eye diameter. Mouth oblique, lower jaw projecting beyond upper one when closed. Maxilla deep, its depth 82.1‒92.7% 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, the first antrorse; a retrorse spine at angle of preoperculum, the posterior margin of which bears 31‒34 serrae. A sharp spine at angle of operculum. Seven branchiostegal rays. Inferior margin 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, densely denticulated on proximal side. Cleithrum and supracleithrum each with 4 or 5 serrae.
TABLE 1.
Measurements as a percentage of standard length of holotype and 2 paratypes of
Lates lakdiva
(220‒256 mm SL); holotype and 3 paratypes of
L. uwisara
(332‒363 mm SL); 27 specimens of
L. calcarifer
(97.6‒315 mm SL); and 11 specimens of
L. japonicus
(134‒263 mm SL). Non-overlapping ranges between species are italicized. Specimen details are given in species accounts of
L. lakdiva
and
L. uwisara
, and Comparative Material.
|
L. lakdiva
|
L. uwisara
|
L. calcarifer
|
L. japonicus
|
| min max |
min max |
min max |
min max |
| Total length |
121 121 |
121 124 |
120 128 |
119 123 |
| Snout to base of last dorsal-fin ray |
82.4 83.2 |
82.6 85.2 |
82.0 88.4 |
82.0 85.8 |
| Snout to base of last anal-fin ray |
84.8 85.4 |
83.3 86.4 |
82.3 88.1 |
82.5 88.9 |
| Preanal length |
73.9 74.8
|
72.9 75.6
|
69.9 76.1 |
67.5 72.3
|
| Prepelvic length |
34.6 36.3 |
34.6 36.5 |
34.4 43.9 |
33.1 38.3 |
| Prepectoral length |
32.9 34.8 |
31.3 33.7 |
31.4 38.7 |
30.2 34.3 |
| Predorsal length |
44.8 45.0 |
44.7 47.2 |
42.0 47.4 |
42.3 45.7 |
| Length of dorsal-fin base |
41.1 42.0
|
43.9 45.0
|
41.3 46.3 |
42.8 45.5 |
| Length of 1st dorsal-fin base |
19.4 19.4
|
21.1 23.0
|
19.6 25.7 |
22.3 26.6
|
| Length of 2nd dorsal-fin base |
18.3 19.2
|
21.0 21.8
|
17.8 21.5 |
18.5 21.0 |
| Dorsal-fin origin to caudal-fin base |
60.2 60.2 |
59.3 62.3 |
58.6 65.0 |
60.9 65.2 |
| Post-dorsal distance |
18.7 18.7 |
16.0 19.4 |
14.3 19.5 |
17.9 20.2 |
| Body depth |
26.6 27.6 |
28.4 32.0 |
28.9 34.6 |
30.5 33.7 |
| Depth from dorsal-fin origin to pelvic-fin origin 28.4 |
29.1 |
30.1 |
33.3 |
30.1 |
35.5 |
31.9 |
35.3 |
| Depth at origin of 2nd dorsal fin 26.9 |
26.9 |
26.9 |
31.1 |
26.6 |
33.6 |
30.5 |
33.3 |
|
Caudal peduncle depth
11. 3
|
12. 1
|
11.6 |
13.3 |
11.9 |
14.6 |
12.5
|
14.0
|
|
Caudal peduncle length
17.1
|
17.5
|
15.8
|
17.6
|
14.3 |
19.6 |
18.2
|
20.1
|
|
Body width at dorsal-fin origin
12.0
|
12.6
|
14.0 |
16.1 |
11.7 |
17.6 |
11.8 |
16.4 |
|
Length of anal-fin base
12.0
|
12.0
|
12.1
|
13.9
|
12.5
|
15.4
|
14.5
|
16.5
|
|
Pectoral-fin length
15.7
|
15.9
|
16.5
|
17.6
|
14.2 |
17.5 |
14.7 |
16.6 |
| Pelvic-fin length 20.1 |
20.7 |
18.5 |
20.7 |
18.4 |
21.9 |
20.1 |
21.6 |
|
Length of dorsal spine I
2.2
|
2.8
|
3.3
|
3.6
|
2.6 |
4.2 |
2.5 |
5.1 |
|
Length of dorsal spine II
5.6
|
6.3
|
5.7
|
6.4
|
5.8 |
7.8 |
6.9
|
9.1
|
| Length of dorsal spine III 17.8 |
18.9 |
16.8 |
20.3 |
16.0 |
21.5 |
17.4 |
21.8 |
|
Length of anal-fin spine II
4.3
|
4.5
|
4.2
|
5.0
|
4.3
|
6.8
|
8.5
|
11.5
|
|
Length of anal-fin spine III
7.4
|
7.4
|
6.4
|
7.1
|
5.0 |
7.7 |
7.3
|
9.3
|
| Head length 35.7 |
35.8 |
35.5 |
37.9 |
35.0 |
39.9 |
32.8 |
36.7 |
|
Snout length
6.7
|
6.8
|
6.8
|
7.5
|
6.6 |
8.4 |
7.2 |
8.7 |
|
Maxilla length
14.6
|
14.6
|
15.2
|
16.8
|
14.1 |
16.9 |
13.4 |
15.5 |
|
Maxilla depth
4.6
|
4.6
|
4.9
|
5.4
|
4.0 |
5.9 |
4.4 |
5.4 |
|
Internarial width
4.8
|
4.8
|
4.1
|
4.3
|
4.2 |
5.7 |
3.9 |
5.3 |
|
Eye diameter
5.5
|
5.6
|
4.4
|
4.7
|
4.7
|
6.9
|
4.9 |
6.7 |
| Interorbital width 5.0 |
5.4 |
5.0 |
5.7 |
4.1 |
5.9 |
4.4 |
5.3 |
| Snout to preopercular posterior margin 24.6 |
25.2 |
23.7 |
25.4 |
23.3 |
26.5 |
22.3 |
25.1 |
| Snout to tip of spine at preopercular angle 26.3 |
26.6 |
26.3 |
27.9 |
25.2 |
29.6 |
24.1 |
27.2 |
First dorsal fin commencing slightly behind pelvic-fin, with 7 spines, third spine longest (III>IV>V>VI>II>VII>I). Base of first dorsal fin subequal to (97.5‒110%) that of second dorsal fin. Second dorsal with 1 spine and 10 or 11 rays. Anal fin commencing beneath base of second-dorsal fin ray 4, with 3 spines, third one longest (III>II>I) and 7 or 8 rays. Pectoral fin with 14 rays, 76.7‒81.1% length of pelvic fin, which has 1 spine and 5 rays. Pelvic-fin spine slightly shorter than dorsal spine IV, longer than dorsal spine V. Distal profiles of pectoral, pelvic, anal and second-dorsal fins rounded. Caudal fin rounded, with 7+9+8+7 rays. Caudal peduncle depth 66.1‒69.1% its length.
Scales ctenoid; body and head scaled, except for snout, throat, preorbital and interorbital regions. Dorsal and anal fins reposed in a scaly sheath. Second-dorsal, caudal, anal and lateral area of pelvic fin densely covered with minute scales. Lateral line with 47‒52 posteriorly notched scales on body, commencing immediately posterior to supracleithrum, extending almost to tip of caudal fin; two rows of pored scales on caudal fin, one above and one below median lateral line. Five scales in transverse line between base of third dorsal-fin spine and lateral line; 9 or
10 in
transverse line between anus and lateral line; 22 circumpeduncular scales.
Coloration.
In 70% alcohol (
Fig. 2
), head and body olive brown, darker above lateral line and on dorsal region of head, lighter below, ventrally creamy yellow. Fins dark olive, interradial membrane of dorsal fin white, darkolive towards distal margin. Second dorsal fin, caudal and anal fins dark olive brown, pectoral and pelvic fins somewhat lighter, pelvic-fin spine almost white.
Etymology.
The specific epithet
Lakdiva
is Sinhala for the island of
Sri Lanka
, here used as a substantive in apposition. We propose Sri Lankan Sea Bass as the common name for this species, which is also known by the local names ‘modha’ (Sinhala) and ‘koduwa’ (Tamil).
Conservation.
The growth of the fisheries industry in
Sri Lanka
has seen the introduction of large numbers of juvenile
Lates
of unknown provenance into the island’s estuaries during the recent past (
RP
, pers. obs.). The effects of these introductions on the population of
L. lakdiva
, are unknown and warrant future investigation.