Research Article 
Corresponding author: Kōji Yokogawa ( gargariscus@ybb.ne.jp ) Academic editor: Nina Bogutskaya
© 2019 Kōji Yokogawa.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Yokogawa K (2019) Morphological differences between species of the sea bass genus Lateolabrax (Teleostei, Perciformes), with particular emphasis on growthrelated changes. ZooKeys 859: 69115. https://doi.org/10.3897/zookeys.859.32624

Morphological differences, including growthrelated changes, were examined in three morphologically similar East Asian sea bass species, Lateolabrax japonicus, L. maculatus and L. latus. In many cases, body measurements indicated specific patterns of growthrelated proportional changes. Lateolabrax latus differed from the other two species in having greater body depth, caudal peduncle depth, caudal peduncle anterior depth, snout length, and upper and lower jaw length proportions. In particular, scatter plots for caudal peduncle anterior depth relative to standard length (SL) in that species indicated complete separation from those of the other two species, being a new key character for identification. Comparisons of L. japonicus and L. maculatus revealed considerable proportional differences in many lengthmeasured characters, including fin lengths (first and second dorsal, caudal and pelvic), snout length, postorbital preopercular width (POPW) and postorbital length. In particular, snout length (SNL) and POPW proportions of the former were greater and smaller for specimens >200 and ≤ 200 mm SL, respectively. Because the scatter plots of these proportions for the two species did not overlap each other in either size range, identification of the species was possible using a combination of the two characters. In addition, scatter plots of the POPW / SNL proportion (%) of L. japonicus and L. maculatus were almost completely separated throughout the entire size range examined (border level 90%), a further aid to identification. The numbers of pored lateral line scales and scales above the lateral line tended to increase and decrease with growth, respectively, in L. japonicus, whereas scales below the lateral line and gill raker numbers tended to increase with growth in L. maculatus. Because the ranges of these meristic characters may therefore vary with specimen size, they are unsuitable for use as key characters. Accordingly, a new key is proposed for the genus Lateolabrax.
Lateolabrax japonicus, Lateolabrax maculatus, Lateolabrax latus, morphology, growth, new key
The sea basses of the genus Lateolabrax (Lateolabracidae) are common East Asian coastal marine fishes (occasionally also occurring in fresh water).
General aspects of small (fingerling) and large (adult) individuals of Lateolabrax japonicus (A, B), L. maculatus (C, D) and L. latus (E, F) in fresh condition. A KPMNI 27449 (91.9 mm SL) B KPMNI 30671 (331.0 mm SL) C uncatalogued specimen (94.3 mm SL) D BSKU 100776 (265.0 mm SL) E KPMNI 29044 (97.1 mm SL) F KPMNI 24656 (369.0 mm SL). A, B, E and F were photographed by Hiroshi Senou (KPM), C and D were photographed by K. Yokogawa.
Lateolabrax latus has been distinguished from L. japonicus by having greater proportions of body and caudal peduncle depth (BD and CPD), more dorsal and anal fin rays (≥15 and ≥9, respectively), fewer scales below the lateral line (≤16) and possessing ventromandibular scale rows (VSRs) (
Lateolabrax maculatus has been characterized by many clear black spots on the body, but this character is also problematic as a few individuals of the species lack such spots (
Thus, morphological identifications of the three Lateolabrax species remain problematic, although genetic studies have shown them to be independent species (
Measurements were based on the following Lateolabrax specimens, which have been deposited in the Laboratory of Marine Biology, Faculty of Science, Kochi University (BSKU), Kanagawa Prefectural Museum of Natural History (KPM), the Kagoshima University Museum (KAUM) and Tokushima Prefectural Museum (TKPM), together with some uncatalogued ones. Because presence of some specialized sea bass populations, which resulted from introgressive hybridization between Lateolabrax japonicus and L. maculatus, have been reported from Japan (Ariake and Yatsushiro Seas) (
Lateolabrax japonicus (229 specimens). BSKU 100789–100804 (16), 100826, KPMNI 9697, 9698, KAUM–I. 82683–82703 (21), 93431–93439 (9), uncatalogued specimens (54) – all Kagawa Pref.; BSKU 101505–101541 (37), Hyogo Pref., Seto Inland Sea; BSKU 100739–100769 (31), 100788, Yamaguchi Pref., Seto Inland Sea; BSKU 66400, KPMNI 9699 – both Uwajima, Ehime Pref., TKPMP 352 (20), Tokushima Pref.; KPMNI 27449, Mie Pref.; KPMNI 30671, Sagami Bay; BSKU 100837, 100839, 100842, 100845, 100846, 100852, 100854, 100855, 100859–100862 (4), 100865, 100867, 100873, 100874, 100876, 100878, 100879, 100882, 100883, 100886, 100888, 100891, 100893, 100897, 100898, 100900–100902 (3), 100904, 100906, 100907 – all Ishikawa Pref.
Lateolabrax maculatus (170 specimens). BSKU 100770–100787 (18), 101787–101826 (40), a wild strain imported from Yantai, China and cultured in Kagawa, Japan; TKPMP 1655 (40), uncatalogued specimens (33), a wild strain imported from China (locality unknown) as aquacultural seeds; BSKU 66398, 66399, 66401–66406 (6), TKPMP 6114, 6140, KPMNI 9686–9689 (4), 9691–9694 (4), uncatalogued specimens (17) – all Uwajima, Ehime Pref. (presumed escapees from nurseries); TKPMP 16897, KPMNI 9696, uncatalogued specimens (2) – all eastern Seto Inland Sea (presumed escapees from nurseries).
Lateolabrax latus (136 specimens). BSKU 101827, Awaji I., Seto Inland Sea; BSKU 100553, 100554, 100556–100561 (6), 101835, TKPMP 372 – all Tokushima Pref.; KAUM–I. 1895 (4) locality unknown; KAUM–I. 25203, 29117, KPMNI 24246–24248 (3), 24252–24256 (5), 24648–24656 (9), 24935–24940 (6) – all Yakushima I.; KAUM–I. 33778, Ikarajima I., Yatsushiro Sea.; KAUM–I. 39049–39051 (3), 39055–39058 (4), 39128, 39129, 61956, 64737, 64738, 66393, 66394, 67090, Tanegashima I.; KAUM–I. 42043, 42044, 51058–51068 (11), 54112, 54668, 57963, 58161, 58162, 61406, 61407, 61577, 63162–63169 (8), 63625, 65483–65485 (3), 65671, 80441–80444 (4), Kagoshima Pref. (mainland); KAUM–I. 66081, 75375, 75660, 75815, 75816, Nagasaki Pref.; KPMNI 21869, 22433, 23429, Shizuoka Pref.; KPMNI 24566, 24579, 24615, 35333, Miyazaki Pref.; KPMNI 26185, 26186, 26992, 28599 (3), 29040, Chiba Pref.; KPMNI 26973, 26975–26979 (5), 26988–26991 (4), Uwajima, Ehime Pref.; KPMNI 29041–29048 (8), 31568, Kochi Pref.; KPMNI 29279, 37509, 37919, 37920, Kanagawa Pref.
Methods of measurements and counts followed
Abbreviation  Abbreviation  
Lengthmeasured body characters  Postorbital preopercular width  POPW  
Standard length  SL  Upper jaw length  UJL 
Preanus length  PAL  Lower jaw length  LJL 
Body depth  BD  Meristic characters  
Body width  BWT  Dorsal fin spine  DFS 
Caudal peduncle depth  CPD  Dorsal fin soft ray  DFR 
Caudal peduncle anterior depth  CPAD  Anal fin spine  AFS 
Caudal peduncle length  CPL  Anal fin ray  AFR 
Predorsal length  PDL  Pectoral fin ray  P_{1}FR 
First dorsal fin (longest spine) length  FDFL  Pelvic fin spine  P_{2}FS 
Second dorsal fin (longest ray) length  SDFL  Pelvic fin ray  P_{2}FR 
Caudal fin length  CFL  Pored scale on lateral line  LLS 
Caudal fin notch depth  CFND  Scale above lateral line  SAL 
Anal fin (longest ray) length  AFL  Scale below lateral line  SBL 
Pectoral fin length  P_{1}FL  Upperlimb gill raker  UGR 
Pelvic fin length  P_{2}FL  Lowerlimb gill raker  LGR 
Pectoral scaly area length  PSAL  Total gill raker  TGR 
Head length  HL  Abdominal vertebra  AV 
Lengthmeasured cephalic characters  Caudal vertebra  CV  
Snout length  SNL  Total vertebra  TV 
Orbital diameter  OD  Others  
Interorbital width  IOW  Dorsocephalic scale row  DSR 
Suborbital width  SOW  Ventromandibular scale row  VSR 
Postorbital length  POL  First anal pterygiophore  FAP 
Scale row and paired fin ray counts were made on the left side of the body, whereas gill rakers were counted on the first gill arch on the right side by separating the upper and lower limbs of the gill arch. Because counts of pelvic finspine (P_{2}FS) and soft rays (P_{2}FRs) showed no variation (P_{2}FS: 1, P_{2}FRs: 5 in all specimens), these counts were omitted from the statistical analyses. Abdominal and caudal vertebrae were counted, and first anal fin pterygiophore morphology observed from radiographs.
Total numbers of recognizable black or faint spots / dots on the left side of the body and middorsal aspect of the caudal peduncle (Fig.
For a lengthmeasured dimension (LD), a growthrelated proportional change pattern is given by the relationship between base dimension [e.g., standard length (SL) or head length (HL)] and the LD proportion (LD / SL or LD / HL). Because the relationship between SL (or HL) and LD is generally expressed by a power regression formula (LD = a SL ^{b}) (allometric growth), the following formula was used (LD / SL = a SL ^{b}^{1}). Accordingly, power regressions were applied for the relationships between SL (or HL) and the LD proportions (Table
Regression parameters and correlation between standard length (SL) or head length (HL) and proportions of lengthmeasured dimensions (LD) [SL = a (LD/SL)^{b}, HL = a (LD/HL)^{b}] of three Lateolabrax species.
Regression  Lateolabrax japonicus  Lateolabrax maculatus  Lateolabrax latus  
a  b  r  a  b  r  a  b  r  
SL–PAL/SL  64.42  0.004  0.092  74.89  0.026  0.524  63.90  0.008  0.270 
SL–BD/SL  44.23  0.108  0.735  29.94  0.029  0.379  33.03  0.021  0.240 
SL–BWT/SL  8.78  0.075  0.471  10.71  0.048  0.455  8.43  0.079  0.466 
SL–CPD/SL  16.55  0.100  0.749  11.48  0.025  0.353  11.32  0.002  0.034 
SL–CPL/SL  22.33  0.007  0.069  19.83  0.019  0.216  21.55  0.010  0.115 
SL–CPAD/SL  21.12  0.091  0.686  14.36  0.014  0.220  15.05  0.009  0.140 
SL–PDL/SL  44.01  0.041  0.574  39.76  0.029  0.513  45.07  0.039  0.711 
SL–FDFL/SL  22.72  0.081  0.407  12.40  0.008  0.065  22.22  0.086  0.541 
SL–SDFL/SL  36.65  0.201  0.762  17.05  0.068  0.443  23.31  0.091  0.485 
SL–CFL/SL  32.62  0.085  0.472  17.40  0.008  0.056  28.45  0.055  0.445 
SL–CFND/SL  9.30  0.115  0.220  2.87  0.077  0.176  25.10  0.296  0.781 
SL–AFL/SL  28.14  0.142  0.713  18.56  0.061  0.474  24.60  0.096  0.553 
SL–P_{1}FL/SL  25.19  0.070  0.581  16.98  0.010  0.109  19.79  0.024  0.270 
SL–P_{2}FL/SL  31.24  0.101  0.701  25.47  0.073  0.682  23.84  0.040  0.357 
SL–HL/SL  42.88  0.054  0.677  38.39  0.036  0.629  46.25  0.066  0.836 
SL–SNL/SL  8.23  0.002  0.047  11.42  0.087  0.664  10.91  0.027  0.456 
SL–OD/SL  65.54  0.431  0.958  42.67  0.364  0.945  55.60  0.368  0.963 
SL–IOW/SL  7.55  0.020  0.173  9.31  0.064  0.601  7.75  0.010  0.082 
SL–SOW/SL  2.26  0.067  0.232  1.80  0.135  0.513  2.04  0.070  0.246 
SL–POPW/SL  5.47  0.045  0.423  13.03  0.094  0.741  7.21  0.008  0.066 
SL–POL/SL  15.94  0.016  0.170  13.46  0.060  0.691  19.07  0.027  0.373 
SL–UJL/SL  19.09  0.061  0.706  20.81  0.083  0.778  22.01  0.071  0.778 
SL–LJL/SL  20.51  0.058  0.700  22.29  0.084  0.782  21.66  0.052  0.629 
SL–PSAL/SL^{1}  8.14  0.130  0.203  
SL–POPW/SNL  71.07  0.030  0.314  90.56  0.031  0.222  65.79  0.020  0.149 
HL–SNL/HL  20.42  0.057  0.530  28.48  0.054  0.453  24.50  0.040  0.533 
HL–OD/HL  109.60  0.400  0.946  79.68  0.338  0.945  93.74  0.323  0.950 
HL–IOW/HL  18.38  0.033  0.246  23.83  0.031  0.292  17.72  0.057  0.359 
HL–SOW/HL  5.90  0.127  0.397  5.55  0.178  0.625  4.98  0.143  0.432 
HL–POPW/HL  14.81  0.090  0.690  26.66  0.022  0.240  16.41  0.061  0.418 
HL–POL/HL  39.87  0.073  0.729  38.83  0.099  0.873  42.78  0.041  0.498 
HL–UJL/HL  44.57  0.009  0.139  51.77  0.049  0.667  47.53  0.006  0.109 
HL–LJL/HL  48.01  0.005  0.092  55.24  0.049  0.713  47.36  0.014  0.237 
Characteristics that changed with growth were evaluated so as to determine if the changes were isometric or allometric, i.e., regressions between SL (or HL) and LD were transformed into natural logarithms (ln) (lnLD = a lnSL + b), and a t test was used to examine slope significance for the null hypothesis (a = 1), according to
To examine interspecific differences in lengthmeasured characters, regressions between SL (or HL) and LD were also logarithmtransformed (lnLD = a lnSL + b), since most characters showed allometric growth (Table
Regression parameters (slope and intercept) and correlation between logarithmtransformed lengthmeasured characters, together with results of t tests to examine significance of slopes for three Lateolabrax species (null hypothesis, slope = 1).
Regression  Lateolabrax japonicus  Lateolabrax maculatus  Lateolabrax latus  
Slope  Intercept  t  Slope  Intercept  t  Slope  Intercept  t  
ln SL–ln PAL  1.004  0.44  1.39  0.974  0.29  7.97***  1.008  0.45  3.25* 
ln SL–ln BD  0.892  0.82  16.35***  0.971  1.21  5.31***  0.979  1.11  2.87* 
ln SL–ln BWT  1.075  2.43  8.05***  1.048  2.23  6.62***  1.079  2.47  6.10*** 
ln SL–ln CPD  0.900  1.80  17.04***  0.975  2.16  4.89***  1.002  2.18  0.40 
ln SL–ln CPL  0.993  1.50  1.05  1.019  1.62  2.86*  0.990  1.53  1.33 
ln SL–ln CPAD  0.909  1.55  14.28***  0.986  1.94  2.92*  1.009  1.89  1.63 
ln SL–ln PDL  0.959  0.82  10.56***  0.971  0.92  7.71***  0.961  0.80  11.72*** 
ln SL–ln FDFL  0.919  1.48  6.72***  1.008  2.09  0.85  0.914  1.50  7.45*** 
ln SL–ln SDFL  0.794  0.97  17.15***  0.932  1.77  6.31***  0.909  1.46  6.42*** 
ln SL–ln CFL  0.914  1.11  7.84***  1.008  1.75  0.70  0.974  1.35  2.55 
ln SL–ln CFND  0.880  2.35  3.41**  1.077  3.55  2.22  0.704  1.38  13.88*** 
ln SL–ln AFL  0.858  1.27  15.17***  0.939  1.68  6.97***  0.904  1.40  7.67*** 
ln SL–ln P_{1}FL  0.930  1.38  10.73***  0.990  1.77  1.41  0.976  1.62  3.25* 
ln SL–ln P_{2}FL  0.899  1.16  14.81***  0.927  1.37  12.06***  0.960  1.43  4.42*** 
ln SL–ln HL  0.946  0.85  13.87***  0.964  0.96  10.46***  0.934  0.77  17.67*** 
ln SL–ln SNL  1.002  2.50  0.67  0.913  2.17  11.57***  0.973  2.22  5.94*** 
ln SL–ln OD  0.569  0.42  50.25***  0.636  0.85  37.39***  0.632  0.59  41.41*** 
ln SL–ln IOW  0.980  2.58  2.64  0.936  2.37  9.71***  0.990  2.56  0.95 
ln SL–ln SOW  1.067  3.79  3.60**  1.135  4.02  7.73***  1.070  3.89  2.94* 
ln SL–ln POPW  1.033  2.84  5.68***  0.943  2.26  7.72***  0.993  2.63  0.69 
ln SL–ln POL  1.014  1.82  2.10  1.060  2.00  12.25***  0.974  1.66  4.56*** 
ln SL–ln UJL  0.939  1.66  15.04***  0.917  1.57  16.02***  0.929  1.51  14.34*** 
ln SL–ln LJL  0.942  1.58  14.74***  0.916  1.50  16.11***  0.948  1.53  9.34*** 
ln SNL–ln POPW  1.026  0.26  4.37***  1.020  0.01  1.71  1.017  0.36  4.19*** 
ln HL–ln SNL  1.057  1.59  9.41***  0.946  1.26  6.65***  1.040  1.41  7.28*** 
ln HL–ln OD  0.600  0.09  44.06***  0.662  0.23  37.38***  0.677  0.06  35.28*** 
ln HL–ln IOW  1.033  1.69  3.82**  0.969  1.43  3.94**  1.057  1.73  4.45*** 
ln HL–ln SOW  1.127  2.83  6.52***  1.178  2.89  10.36***  1.143  3.00  5.55*** 
ln HL–ln POPW  1.090  1.91  14.36***  0.978  1.32  3.19*  1.061  1.81  5.32*** 
ln HL–ln POL  1.073  0.92  15.93***  1.099  0.95  23.15***  1.041  0.85  6.62*** 
ln HL–ln UJL  0.991  0.81  2.11  0.951  0.66  11.57***  0.994  0.74  1.27 
ln HL–ln LJL  0.995  0.73  0.19  0.952  0.59  13.19***  1.014  0.75  2.81* 
Because some meristic counts tended to increase significantly with growth (Table
Regression parameters (slope and intercept) and correlation between standard length (SL) and meristic counts of three Lateolabrax species (null hypothesis, slope = 0).
Regression  Slope  Intercept  r  t 
Lateolabrax japonicus  
SL–DFS counts  0.00008  12.87  0.019  0.28 
SL–DFR counts  0.00081  13.13  0.130  2.05 
SL–AFR counts  0.00048  7.56  0.089  1.34 
SL–P_{1}FR counts  0.00047  16.96  0.086  1.30 
SL–LLS counts  0.01207  77.01  0.343  5.50*** 
SL–SAL counts  0.00258  15.84  0.258  3.98** 
SL–SBL counts  0.00057  18.57  0.046  0.68 
SL–UGR counts  0.00111  8.63  0.126  1.90 
SL–LGR counts  0.00025  17.93  0.027  0.41 
SL–TGR counts  0.00086  26.56  0.073  1.10 
SL–AV counts  0.00017  16.00  0.073  0.93 
SL–CV counts  0.00068  20.02  0.108  1.38 
SL–TV counts  0.00051  36.02  0.083  1.80 
SL–Dot counts  0.02297  12.69  0.198  2.90* 
Lateolabrax maculatus  
SL–DFS counts  0.00046  12.95  0.153  2.00 
SL–DFR counts  0.00028  13.03  0.066  0.86 
SL–AFS counts  0.00008  2.98  0.104  1.36 
SL–AFR counts  0.00097  7.34  0.217  2.88 
SL–P_{1}FR counts  0.00079  16.33  0.190  2.50 
SL–LLS counts  0.00261  73.45  0.099  1.30 
SL–SAL counts  0.00008  15.52  0.009  0.24 
SL–SBL counts  0.00477  18.17  0.409  5.72*** 
SL–UGR counts  0.00139  6.40  0.173  2.24 
SL–LGR counts  0.00330  14.70  0.507  7.49*** 
SL–TGR counts  0.00469  21.11  0.408  5.68*** 
SL–AV counts  0.00026  15.97  0.135  1.67 
SL–CV counts  0.00022  19.00  0.089  1.09 
SL–TV counts  0.00003  34.97  0.012  0.02 
SL–Spot counts  0.02333  33.89  0.126  1.62 
Lateolabrax latus  
SL–DFS counts  0.00026  13.05  0.092  1.08 
SL–DFR counts  0.00041  15.11  0.011  1.20 
SL–AFS counts  0.00002  3.00  0.001  0.34 
SL–AFR counts  0.00026  9.06  0.002  0.55 
SL–P_{1}FR counts  0.00026  16.20  0.004  0.73 
SL–LLS counts  0.00264  72.91  0.169  1.99 
SL–SAL counts  0.00063  13.86  0.079  0.92 
SL–SBL counts  0.00013  15.79  0.014  0.16 
SL–UGR counts  0.00045  6.83  0.072  0.83 
SL–LGR counts  0.00109  17.11  0.176  2.07 
SL–TGR counts  0.00154  23.94  0.166  1.95 
SL–AV counts  0.00004  16.03  0.018  0.22 
SL–CV counts  0.00005  19.92  0.014  0.17 
SL–TV counts  0.00001  35.95  0.004  0.05 
SL–Dot counts  0.06278  24.74  0.365  4.53*** 
In the above statistical inferences, due to multiple tests being applied simultaneously in each case, multiple comparisons were introduced for the t test results, risk percentages for the t values being corrected according to total test counts, using the HolmBonferroni method (
In the three Lateolabrax species, slopes of the logarithmtransformed regressions were significantly different from 1 (allometric growth) for most characters (Table
Relationships between standard length and proportions of some lengthmeasured body characters which exhibited prominent plot separation among three Lateolabrax species. For character abbreviations, see Figure
Similar patterns of growthrelated proportional changes common to the three species were observed for some characters, viz., significant positive allometric growth (proportions increased with growth) in body width and significant negative allometric growth (proportions decreased with growth) in head (HL) and predorsal length (PDL), and second dorsal, anal and pelvic fin (longest ray) lengths (SDFL, AFL and P_{2}FL), although patterns of the regression curves or plot distributions for the three species sometimes varied from one another (Figs
For lengthmeasured dimensions (LD) of cephalic characters, SLbased (SL–LD / SL) and HLbased relationships (HL–LD / HL) are illustrated in pairs with multiple specific plots in Figure
Growthrelated proportional change patterns based on SL and HL were inconsistent with each other for some characters in L. japonicus and L. latus, e.g., snout length (SNL) of L. japonicus was isometric and positively allometric for SL and HL, respectively; that of L. latus was negatively and positively allometric for SL and HL, respectively (Fig.
As well as some body characters, specific proportional change patterns were recognized for some characters, e.g., SLbased relationships of POPW, exhibiting isometric growth in L. japonicus, and positive and negative allometric growth in L. maculatus and L. latus, respectively (Fig.
The relationship between SL and pectoral scaly area length (PSAL) in L. latus was well fitted to a power regression (like many other body and cephalic lengthmeasured characters), the PSAL / SL proportion gradually decreasing with growth (Fig.
Plot separation of L. latus from the other two species was prominent for vertical body dimensions of body depth (BD), caudal peduncle depth (CPD) and caudal peduncle anterior depth (CPAD), L. japonicus and L. maculatus both showing significant negative allometric growth, the degree of relative decrease being especially acute in the former. Although BD of L. latus showed slight negative allometric growth, CPD and CPAD were regarded as isometric (Fig.
Plot separation of first and second dorsal (FDFL and SDFL), caudal (CFL) and pectoral (P_{1}FL) fin lengths was also apparent between L. japonicus and L. maculatus (Fig.
Upward plot separation of L. latus from the other two species was prominent for SNL and upper and lower jaw lengths (UJL and LJL), there being almost no overlap with L. maculatus and only modest overlap with L. japonicus (Fig.
On the other hand, plot separation between L. japonicus and L. maculatus was prominent for SNL, POPW and POL (Fig.
POPW proportional to SNL is shown graphically in Figure
The t tests of regressions between SL and meristic counts (null hypothesis, slope = 0) proved significant for scales on (LLS) and above the lateral line (SAL) in L. japonicus, and scales below the lateral line (SBL) and gill raker counts [lower limb and total (LGR and TGR, respectively)] in L. maculatus (Table
Figure
Some examples of L. japonicus and L. latus had small and fine dots, respectively, on the lateral body region (Fig.
Postjuvenile specimens (> ca. 70 mm SL) of the three Lateolabrax species had a pair of scale rows (dorsocephalic scale rows, DSRs) extending forward from the interorbital area, which was densely covered with fine scales (Fig.
Squamation on dorsal head regions of Lateolabrax japonicus (A, B), L. maculatus (C, D) and L. latus (E, F). Thick arrows indicate anterior nostrils, thin arrows indicate anterior edges of dorsocephalic scale rows. A KAUM–I. 93435 (137.0 mm SL) B BSKU 100803 (265.2 mm SL) C uncatalogued specimen (104.9 mm SL) D BSKU 100773 (254.2 mm SL) E KAUM–I. 39058 (114.2 mm SL) F KPMNI 24255 (240.1 mm SL).
Some individuals of the three Lateolabrax species had a pair of ventromandibular scale rows (VSRs), VSR status by body size being summarized in Table
Frequencies (%) of ventromandibular scale row status in three Lateolabrax species.
SL range (mm)  Anterior part  Posterior part  
Present  Vestigial  Absent  Present  Vestigial  Absent  
Lateolabrax japonicus  
≤100  0.0  0.0  100.0  0.0  0.0  100.0 
100–200  0.0  14.3  85.7  10.7  21.4  67.9 
200–300  5.0  25.0  70.0  35.0  30.0  35.0 
300–400  5.3  26.3  68.4  31.6  57.9  10.5 
>400  25.0  50.0  25.0  37.5  62.5  0.0 
Lateolabrax maculatus  
≤100  0.0  0.0  100.0  0.0  0.0  100.0 
100–200  0.0  0.0  100.0  0.0  0.0  100.0 
200–300  0.0  18.2  81.8  22.7  54.5  22.7 
300–400  5.6  55.6  38.9  55.6  27.8  16.7 
>400  12.1  51.5  36.4  84.8  15.2  0.0 
Lateolabrax latus  
≤100  0.0  13.3  86.7  6.7  13.3  80.0 
100–200  70.5  18.0  11.5  49.2  19.7  31.1 
200–300  95.1  4.9  0.0  97.6  2.4  0.0 
300–400  100.0  0.0  0.0  100.0  0.0  0.0 
>400  100.0  0.0  0.0  100.0  0.0  0.0 
All three Lateolabrax species had a welldeveloped first anal pterygiophore (FAP), which comprised a short thin platelike anterior part and a long thick spiny posterior part (Fig.
Radiographs of first anal pterygiophores in Lateolabrax japonicus (A–D), L. maculatus (E–H) and L. latus (I–L), according to body size by species. A KAUM–I. 82683 (65.6 mm SL) B BSKU 100883 (96.8 mm SL) C BSKU 100756 (252.4 mm SL) D KPMNI 9697 (317.0 mm SL) E uncatalogued specimen (58.4 mm SL) F TKPMP 16556 (95.2 mm SL) G BSKU 100771 (250.8 mm SL) H KPMNI 9686 (364.0 mm SL) I KAUM–I. 18954 (70.3 mm SL) J KAUM–I. 64737 (SL 94.2 mm) K KPMNI 24650 (265.4 mm SL) L KAUM–I. 57963 (342.0 mm SL).
Analyses of covariance (ANCOVA) for regressions of logarithmtransformed lengthmeasured characters by pairwise comparisons for the three Lateolabrax species indicated significant differences in the slopes or intercepts of all such characters (Table
Results of analysis of covariance (ANCOVA) (t test) to compare regression parameters of logarithmtransformed lengthmeasured characters between three Lateolabrax species.
Regression  L. japonicus × L. maculatus  L. japonicus × L. latus  L. maculatus × L. latus  

Slope  Intercept  Slope  Intercept  Slope  Intercept  
ln SL–ln PAL  7.00***  –  1.03  6.61***  7.08***  – 
ln SL–ln BD  9.03***  –  8.16***  –  0.91  26.57*** 
ln SL–ln BWT  2.34  6.92***  0.22  2.58*  2.22  9.23*** 
ln SL–ln CPD  9.51***  –  10.97***  –  3.26  26.59*** 
ln SL–ln CPL  2.81  2.97*  0.29  9.35***  2.69  11.00*** 
ln SL–ln CPAD  9.41***  –  10.18***  –  2.91  36.84*** 
ln SL–ln PDL  2.22  11.60***  0.25  10.07***  1.83  21.83*** 
ln SL–ln FDFL  5.75***  –  0.30  5.13***  5.99***  – 
ln SL–ln SDFL  8.52***  –  6.02***  –  1.23  18.51*** 
ln SL–ln CFL  6.05***  –  3.45*  –  1.86  16.84*** 
ln SL–ln CFND  3.99**  –  3.49*  –  7.37***  – 
ln SL–ln AFL  6.28***  –  2.88  12.25***  2.25  11.23*** 
ln SL–ln P_{1}FL  6.17***  –  4.24**  –  1.26  12.21*** 
ln SL–ln P_{2}FL  3.07  9.89***  5.18***  –  2.96  16.28*** 
ln SL–ln HL  3.45*  –  1.82  5.42***  5.30***  – 
ln SL–ln SNL  9.97***  –  3.68*  –  5.53***  – 
ln SL–ln OD  5.26***  –  4.66***  –  0.26  28.99*** 
ln SL–ln IOW  4.29**  0.73  10.95***  4.27**  –  
ln SL–ln SOW  2.64  7.96***  0.08  5.20***  2.15  12.35*** 
ln SL–ln POPW  10.37***  –  3.61*  –  4.15**  – 
ln SL–ln POL  5.43***  –  3.90**  –  10.54***  – 
ln SL–ln UJL  3.42*  –  1.44  25.97***  1.55  26.46*** 
ln SL–ln LJL  4.05**  –  0.79  22.93***  3.76*  – 
ln SNL–ln POPW  0.48  33.61***  0.76  27.56***  0.18  44.42*** 
ln HL–ln SNL  11.07***  –  1.82  23.86***  7.76***  – 
ln HL–ln OD  4.84***  –  5.29***  –  1.02  28.82*** 
ln HL–ln IOW  5.47***  –  1.52  7.78***  5.92***  – 
ln HL–ln SOW  1.95  9.36***  0.46  6.42***  1.14  15.08*** 
ln HL–ln POPW  12.17***  –  2.40  2.74*  6.34***  – 
ln HL–ln POL  4.04**  –  4.15**  –  7.64***  – 
ln HL–ln UJL  6.89***  –  0.38  22.63***  6.19***  – 
ln HL–ln LJL  7.92***  –  2.84  3.37**  9.71***  – 
Although the MannWhitney U tests for pairwise comparisons of meristic characters of the three species found significant differences in many, significance was not apparent for others, including counts of vertical fin rays [dorsal fin spines (DFSs), DFRs and AFRs] between L. japonicus and L. maculatus, and vertebrae [abdominal vertebrae (AVe), CVe and TVe] between L. japonicus and L. latus (Table
Results of the MannWhitney U test (z values) to compare meristic counts between three Lateolabrax species.
Character  L. japonicus × L. maculatus  L. japonicus × L. latus  L. maculatus × L. latus 
DFS counts  0.37  3.00*  3.64** 
DFR counts  0.12  16.22***  15.60*** 
AFS counts  0.00  1.29  0.64 
AFR counts  1.39  14.64***  14.11*** 
P_{1}FR counts  5.69***  10.62***  5.77*** 
LLS counts  11.53***  13.74***  0.89 
SAL counts  2.04  11.50***  11.47*** 
SBL counts  3.57**  14.43***  13.88*** 
UGR counts  14.31***  14.58***  0.65 
LGR counts  15.45***  8.83***  11.76*** 
TGR counts  16.54***  15.13***  7.81*** 
AV counts  4.23***  0.64  4.15*** 
CV counts  13.58***  0.01  13.45*** 
TV counts  14.82***  0.73  14.09*** 
Standard errors (SEs) for regression lines between logarithmtransformed SL and lengthmeasured characters, and between SL and meristic characters are summarized in Table
Standard errors for morphological character regressions of three Lateolabrax species.
Regression  L. japonicus  L. maculatus  L. latus 
ln SL–ln PAL  0.024  0.029  0.015 
ln SL–ln BD  0.057  0.050  0.043 
ln SL–ln BWT  0.080  0.064  0.077 
ln SL–ln CPD  0.051  0.046  0.036 
ln SL–ln CPL  0.055  0.060  0.044 
ln SL–ln CPAD  0.055  0.044  0.031 
ln SL–ln PDL  0.033  0.033  0.020 
ln SL–ln FDFL  0.103  0.084  0.068 
ln SL–ln SDFL  0.094  0.096  0.084 
ln SL–ln CFL  0.085  0.095  0.068 
ln SL–ln CFND  0.273  0.299  0.119 
ln SL–ln AFL  0.079  0.079  0.074 
ln SL–ln P_{1}FL  0.056  0.063  0.045 
ln SL–ln P_{2}FL  0.058  0.053  0.054 
ln SL–ln HL  0.034  0.031  0.022 
ln SL–ln SNL  0.044  0.067  0.027 
ln SL–ln OD  0.074  0.087  0.053 
ln SL–ln IOW  0.066  0.059  0.065 
ln SL–ln SOW  0.160  0.155  0.140 
ln SL–ln POPW  0.050  0.058  0.060 
ln SL–ln POL  0.057  0.044  0.035 
ln SL–ln UJL  0.035  0.046  0.029 
ln SL–ln LJL  0.034  0.046  0.033 
ln SNL–ln POPW  0.052  0.097  0.068 
SL–DFS counts  0.515  0.424  0.299 
SL–DFR counts  0.649  0.607  0.420 
SL–AFS counts  0.000  0.109  0.086 
SL–AFR counts  0.626  0.629  0.581 
SL–P_{1}FR counts  0.624  0.589  0.432 
SL–LLS counts  3.828  3.725  1.623 
SL–SAL counts  1.117  0.614  0.837 
SL–SBL counts  1.394  1.516  1.009 
SL–UGR counts  1.020  1.131  0.659 
SL–LGR counts  1.073  0.804  0.644 
SL–TGR counts  1.366  1.507  0.963 
SL–AV counts  0.155  0.279  0.191 
SL–CV counts  0.420  0.370  0.336 
SL–TV counts  0.426  0.414  0.333 
The present study revealed that most body proportions of the three Lateolabrax species change with growth (Table
On the other hand, taxonomic and related literature on Lateolabrax have commonly noted the diagnostic importance of ranges and / or averages of body proportions (e.g.,
Proportional range comparisons of head length [HL, % of standard length (SL)] in Lateolabrax japonicus (upper graph, axis labelled BD / SL) and orbital diameter (OD, % of HL) in L. maculatus (lower graph, axis labelled OD / HL) in the present study and previous literature. Data based on A present study B
Differing growthrelated proportional change patterns in the three Lateolabrax species include preanus length (PAL) (Fig.
As in many other fishes (
Growthrelated proportional change patterns of lengthmeasured cephalic characters (based on SL and HL) were sometimes inconsistent in L. japonicus and L. latus (Fig.
The proportional values (percentages) of proportions subject to allometric growth are correlated with the base dimension (e.g., SL and HL). In Figure
Because most of the lengthmeasured characters of the three Lateolabrax species were subject to allometric growth (Table
Counts of pored scales on the lateral line (LLSs) and scales above the lateral line (SALs) tended to increase and decrease with growth, respectively, in L. japonicus (Fig.
The growthrelated status of dots / spots on the lateral body region also varied among the three Lateolabrax species. In L. japonicus and L. latus, although dots appeared in some smaller specimens (up to 260.6 and 254.8 mm SL, respectively), they disappeared with growth (Fig.
The proportional growthrelated change pattern of pectoral scaly area length (PSAL) in L. latus closely fitted a power regression (Fig.
Lateolabrax latus is typically characterized by a deeper body, represented by BD and CPD. However, neither character provides unequivocal identification due to the range overlap for proportional BD and CPD between L. latus and L. japonicus (
The CPAD proportion may be a useful feature for specific identification, since it can also be determined from illustrations and photographs of Lateolabrax species. For instance, an illustration of “L. japonicus (as Percalabrax japonicus)” in Fauna Japonica (
In addition to caudal peduncle stoutness in L. latus,
Caudal fin notch depth (CFND) has been recently proposed as a new character for distinguishing L. latus from the other two species, the former having a shallower CFND than the others (
Among the lengthmeasured cephalic characters of L. latus, plot separation of that species from the others was marked for snout length (SNL) (Fig.
The UJL and LJL plots for all three species (SLbased relationships) were well clustered around their regression curves (high negative allometry), but could not be distinguished from one another vertically (Fig.
The original description of L. latus included several diagnostic meristic characters, including counts of DFRs, AFRs and SBLs (
In addition to lengthmeasured and meristic characters in the original description of L. latus a further diagnostic feature proposed was the possession of ventromandibular scale rows (VSRs) (
The diagnosis accompanying the original description of L. latus included ventral (pelvic fins) generally dusky, unlike in L. japonicus (
Recent keys for identification of L. japonicus and L. maculatus have adopted SNL, that of L. maculatus supposedly being relatively shorter than that of the former (
On the other hand, postorbital preopercular width (POPW) is a notable dimension, showing a contrasting pattern to SNL, i.e., plots of proportional POPW in small (< 200 mm SL) L. maculatus shifted upward and separated completely from those of similar sized L. japonicus (border levels ca. 7.5% and 23% for SL and HLbased relationships, respectively), although larger specimens (> 200 mm SL) of the two species had some overlap due to the relative decrease of POPW with growth (highly negative allometry) in the former (Fig.
Proportional differences between L. japonicus and L. maculatus were also apparent in many of the fin lengths (first and second dorsal, caudal and pectoral), proportions of the former being distinctly greater than those of the latter in smaller specimens (< ca. 200 mm SL), although plots of the two species overlapped in the larger size class (> ca. 200 mm SL), due to the relative fin lengths decreasing and not changing with growth in the former and latter species, respectively (Fig.
Although
On the other hand, caudal and total vertebral counts (CV and TV, respectively), in which dominant counts were almost completely replaced between L. japonicus and L. maculatus (20 and 19 CVe, 36 and 35 TVe, for the former and latter, respectively) (Fig.
Although L. maculatus typically possessed many black spots on the body, individual spot counts and patterns varied considerably (
A morphological difference in the first anal pterygiophore (FAP) between L. japonicus and L. maculatus was initially noted by
Standard errors (SEs) for the lengthmeasured and meristic character regressions, which indicated degrees of morphological variation, were generally lowest in L. latus (Table
The present study demonstrated a number of growthrelated morphological changes in the three Lateolabrax species, including some new key characters for identification. Despite the number of taxonomic descriptions and studies of Lateolabrax, such features have remained obscure due to the limited numbers of specimens examined and an inherent belief that fish morphology is stable regardless of growth, notwithstanding some recent unique allometric approaches to fish morphology and taxonomy (e.g.,
a^{1}  Caudal peduncle anterior depth [% of standard length (SL)] > 15%. Snout length (% of SL) > 9%. Upper and lower jaw length [% of head length (HL)] > 45% and 49%, respectively. Dorsal fin rays 15–16 [rarely 14 (7.4%)]. Anal fin rays 9 (usually)–11 [rarely 8 (11.0%)]  Lateolabrax latus 
a^{2}  Caudal peduncle anterior depth (% of SL) ≤ 15%. Snout length (% of SL) ≤ 9%. Upper and lower jaw length (% of HL) ≤ 45% and 49%, respectively. Dorsal fin rays 14 or fewer. Anal fin ray counts 8 or fewer (rarely 9)  b 
b^{1}  Postorbital preopercular width (POPW) [% of snout length (SNL)] < 90% [POPW (% of SL) < 7.5% in specimens ≤ 200 mm SL; SNL (% of SL) > 7.7% in specimens > 200 mm SL]. Caudal vertebrae 20 (usually)–21 [rarely 19 (13.5%)]; total vertebrae 36 (usually)–37 [rarely 35 (13.5%)]. First anal pterygiophore modestly arched in specimens ≥ 90 mm SL. Spots / dots absent on body in specimens > 260 mm SL (although some specimens ≤ 260 mm SL have some dots restricted to upper part than lateral line)  Lateolabrax japonicus 
b^{2}  Postorbital preopercular width (POPW) [% of snout length (SNL)] ≥ 90% [POPW (% of SL) ≥ 7.5% in specimens ≤ 200 mm SL; SNL (% of SL) ≤ 7.7% in specimens > 200 mm SL]. Caudal vertebrae 18–19 (usually) [rarely 20 (9.2%)]; total vertebrae 34–35 (usually) [rarely 36 (6.6%)]. First anal pterygiophore straight. Usually many clear black spots on lateral and dorsal body regions (usually even on lower part than lateral line)  Lateolabrax maculatus 
The author is grateful to Drs. Hiroshi Senou (KPM), Hiroyuki Motomura (KAUM) and Hiromitsu Endo (BSKU) for the loan of registered specimens of Lateolabrax species. Dr. Motomura also enabled registration of additional L. japonicus specimens to KAUM. Dr. Senou provided some photographs of fresh KPM specimens. Mr. Taiga Naito (BSKU) assisted with radiography and some measurements. Dr. Shi Dong (Tianjin Normal University) advised on translation of some Chinese literature. Dr. Endo, Mr. Hirokazu Kishimoto (Shizuoka City, Japan), Mr. Taiji Kurozumi (Natural History Museum and Institute, Chiba), Dr. Brian L. Sidlauskas (Oregon State University) and Mr. Ikuo Wakabayashi (Wildlife Research Society of Shima Peninsula) helped with provision of literature. Finally, I wish to thank Dr. Graham S. Hardy (Ngunguru, New Zealand) for checking the manuscript.