TABLE 1. Examples of previous studies on phenotypic variation in populations of fossil fishes.

Species Locality Age Environment Objective Characters Source
Kenyaichthys kipkechi Lukeino Formation, Tugen Hills, (Kenya) late Miocene Freshwater to brackish environment Description of Kenyaichthy; Phylogenetic analyses Various morphometric and meristic characters Altner and Reichenbacher (2015)
Thaumaturus intermedius, Atractosteus messelensis Messel Formation (Germany) middle Eocene Freshwater lake Phenotypic variation Meristic counts of vertebrae, rays and supports of the caudal fin; Measurements of various characters from the skull, intermuscular bones, axial skeleton and ganoin patterns Micklich and Klappert (2004)
Lepisosteus bemisi, Atractosteus simplex, A. messelensis, A. atrox, Cuneatus cuneatus, Cuneatus wileyi Green River Formation (USA), Messel Formation (Germany) early-middle Eocene Freshwater lake Phenotypic variation Various meristic and ratio characters from the skull, fins, and postcranial axial skeleton Grande (2010)
Amyzon aggregatum Horsefly beds,

 

British Columbia (Canada)

middle Eocene Freshwater lake Microstratigraphic analyses of phenotypic variation Meristic counts of vertebrae, fin rays and anal pterygiophores Barton and Wilson (1999)
Scaumenacia curta Escuminac Formation (Canada) Late Devonian Estuarine (brackish/fluctuating salinity) Phenotypic variation Skull shape, dermal bone configuration Cloutier (1997)
Semionotus Newark Basin,

 

New Jersey (USA)

Late Triassic - Early Jurassic Freshwater lakes Estimation of speciation rate Dorsal-ridge scales, body shape McCune (1996)
Semionotus Towaco Formation, Newark Basin,

 

New Jersey (USA)

Early Jurassic Freshwater lake Stratigraphical distribution Dorsal-ridge scales McCune (1990)
Gasterosteus doryssus Truckee Formation, Nevada (USA) Miocene Saline lake Temporal variation in morphology Meristic counts of dorsal spines, predorsal pterygiophores, dorsal and anal fin rays; Measurements of pelvic structures and body length Bell and Haglund (1982),

 

Bell et al. (1985),

 

Bell and Legendre (1987)

Kerocottus divaricatus
K. pontifex, 
K. hypoceras,
Kerocottus sp.,
Myoxocephalus idahoensis
Glenns Ferry Formation, Idaho (USA) Pliocene Freshwater Rift lake Intralacustrine speciation 14 characters of preopercles Smith (1987)

TABLE 2. Mean ± standard deviation and range (in parentheses) of morphometric and meristic characters for specimens of Prolebias rhenanus, Pr. stenoura and Paralebias cephalotes.

Character Prolebias rhenanus
(n = 67)
Prolebias stenoura
(n = 40)
Paralebias cephalotes
(n = 141)
Measurements (mm):      
Standard length 23.4 ± 3.8
(13.9-33.5)
35.9 ± 7.9
(19.0-51.0)
25.1 ± 3.0
(19-38.8)
Precaudal vertebral column length 7.6 ± 1.6
(4.0-12)
11.0 ± 3.1
(5.0-15.9)
6.9 ± 1.1
(4.9-12)
Caudal vertebral column length 9.7 ± 1.3
(5.6-12.3)
15.2 ± 3.2
(8.3-20.2)
11.4 ± 1.3
(8.1-15.5)
Dorsal fin base length 3.0 ± 0.3
(2.2-3.6)
4.5 ± 1.1
(2.3-6.9)
2.5 ± 0.5
(1.4-4.2)
Anal fin base length 3.3 ± 0.4
(2.6-4.1)
4.6 ± 1.3
(2.3-8.5)
3.4 ± 0.6
(2.1-5.6)
       
Meristic:      
Total vertebrae number 28.5 ± 0.7
(27-30)
30.0 ± 0.7
(29-31)
29.5 ± 1.0
(27-32)
Precaudal vertebrae number 11.9 ± 0.3
(11-12)
12.0 ± 0.3
(11-13)
10.4 ± 0.6
(10-12)
Caudal vertebrae number 16.7 ± 0.6
(16-18)
18.1 ± 0.7
(17-19)
19.2 ± 0.9
(17-21)
Dorsal pterygiophore number 10.1 ± 0.9
(8-12)
12.6 ± 1.3
(11-16)
8.6 ± 1.2
(6-11)
Anal pterygiophore number 11.0 ± 0.8
(9-13)
14.5 ± 1.2
(12-19)
12.9 ± 1.3
(10-16)

 

 

 TABLE 3. Coefficient of variation (COV) for morphometric and meristic characters.

Character Coefficient of Variation
Prolebias rhenanus
(n = 67)
Prolebias stenoura
(n = 40)
Paralebias cephalotes
(n = 141)
 Measurements (mm):      
Standard length 5.5 6.9 3.5
Total vertebral column length 5.2 8.5 3.9
Precaudal vertebral column length 10.8 13.5 7.7
Caudal vertebral column length 6.4 9.0 4.6
Dorsal fin base length 10.8 16.8 24.0
Anal fin base length 9.8 18.4 13.8
       
Meristic:      
Total vertebrae number 2.4 2.2 3.4
Precaudal vertebrae number 2.9 2.9 5.9
Caudal vertebrae number 3.5 3.6 4.7
Dorsal pterygiophore number 8.8 10.3 13.5
Anal pterygiophore number 7.5 8.4 10.3

 

TABLE 4. Correlation matrix (correlation coefficient below the diagonal; p-values above the diagonal) for fin vs. vertebral and meristic vs. morphometric characters of Prolebias rhenanus. Significant correlations (α = 0.05) are highlighted in bold face fonts. Abbreviations for morphometric characters: SL, standard length; TVL, total length of vertebral column; PCL and CL, length of precaudal and caudal region of vertebral column; DPL and APL, length of dorsal and anal fin bases. Abbreviations for meristic characters: TV, total number of vertebrae; PV and CV, number of precaudal and caudal vertebrae; DP and AP, number of dorsal and anal pterygiophores.

  SL DPL APL TVL PCL CL DP AP TV PCV CV
SL             0.949 0.195 0.120 0.478 0.477
DPL       0.0001 0.0043 0.0358 0.0003 0.783 0.407 0.596 0.343
APL       7.53×10-5 0.0169 9.18×10-7 0.920 0.641 0.886 0.724 0.986
TVL   0.466 0.481       0.949 0.190 0.0914 0.424 0.589
PCL   0.358 0.303       0.604 0.172 0.130 0.424 0.391
CL   0.267 0.577       0.579 0.480 0.325 0.374 0.22
DP -0.0115 0.579 -0.0179 -0.0115 -0.0923 -0.0986     0.052 0.9324 0.234
AP 0.199 -0.0428 0.0724 0.201 0.210 -0.109     0.358 0.0238 0.0682
TV -0.290 0.157 -0.0273 -0.314 -0.283 -0.186 0.453 -0.211      
PCV -0.156 0.117 -0.0779 -0.175 -0.175 0.195 0.024 -0.545      
CV -0.0988 0.132 -0.0024 -0.0751 -0.119 -0.170 0.228 -0.295      


TABLE 5.
Correlation matrix (correlation coefficient below the diagonal; p-values above the diagonal) for fin vs. vertebral and meristic vs. morphometric characters of Prolebias stenoura. Significant correlations (α = 0.05) are highlighted in bold face fonts. Abbreviations are the same as in Table 4.

  SL DPL APL TVL PCL CL DP AP TV PCV CV
SL             0.629 0.907 0.580 0.219 0.774
DPL       0.553 0.899 0.628 0.103 0.366 0.185 0.621 0.252
APL       0.112 0.451 0.0444 0.879 0.0138 0.299 0.0758 0.0868
TVL   0.099 0.262       0.629 0.907 0.580 0.219 0.774
PCL   0.0212 0.126       0.292 0.584 0.770 0.396 0.737
CL   0.0811 0.328       0.862 0.558 0.915 0.220 0.681
DP -0.0994 0.327 0.0313 -0.0994 -0.215 -0.0342     0.746 0.251 0.667
AP 0.0214 -0.166 0.431 0.0214 -0.101 0.108     0.344 0.106 0.0762
TV -0.114 -0.268 0.212 -0.114 -0.0604 0.0219 -0.0849 0.212      
PCV -0.250 -0.102 -0.354 -0.250 -0.174 -0.249 0.292 -0.354      
CV 0.0482 -0.190 0.282 0.0482 0.0563 0.0689 -0.0885 0.318      


TABLE 6.
Correlation matrix (correlation coefficient below the diagonal; p-values above the diagonal) for fin vs. vertebral and meristic vs. morphometric characters of Paralebias cephalotes. Significant correlations (α = 0.05) are highlighted in bold face fonts. Abbreviations are the same as in Table 4.

  SL DPL APL TVL PCL CL DP AP PCV CV TV
SL             0.458 0.352 0.355 0.323 0.749
DPL       0.0001 0.0165 1.04×10-5 9.44×10-6 0.557 0.603 0.322 0.582
APL       8.92×10-8 0.0003 6.92×10-9 0.185 7.02×10-4 0.295 0.377 0.909
TVL   0.322 0.436       0.394 0.339 0.556 0.192 0.430
PCL   0.204 0.302       0.915 0.395 0.204 0.344 0.934
CL   0.366 0.468       0.152 0.418 0.0444 0.0023 0.145
DP 0.0820 0.463 0.146 0.0943 0.0118 0.158     0.735 0.651 0.986
AP -0.0884 0.0558 0.314 -0.0907 -0.0807 -0.0770     0.474 0.849 0.584
PCV -0.0895 -0.0503 -0.101 -0.0570 0.123 -0.193 -0.0421 -0.0765      
CV 0.0847 0.0850 0.0759 0.112 -0.0812 0.258 0.0501 0.0181      
TV 0.0310 0.0533 0.0111 0.0763 -0.008 0.141 -0.0022 -0.0584