Corresponding author: L. Lee Grismer (
Academic editor Uwe Fritz
This study re-analyzes morphometric and meristic data among island night lizards,
The California Channel Islands comprise the western limits of the California Borderlands—one of the most tectonically active areas in North America. Distributed across these eight islands are a suite of endemic vertebrates that continue to serve as exemplary models for studying the evolutionary patterns and processes of island radiations (
Colored dots denote the distribution of
Considerable high-quality field research on the ecology of the three populations of
All morphological analyses were based on the raw data set of
We followed a standardized statistical protocol for morphological analyses (
Because preliminary Student
One-way analyses of variance (
Separate and concatenated principal component analyses (
A subsequent supervised analysis, discriminant analysis of principal components (
Comparing the results recovered here with those of
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San Clemente Island | 0.007 | 0.04 | 0.006 | ||||||
Santa Barbara Island | 0.03 | ||||||||
San Nicolas Island | |||||||||
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San Clemente Island | 0.0005 | 0.009 | |||||||
Santa Barbara Island | |||||||||
San Nicolas Island | 0.02 | 0.004 |
Principal component analyses (A, C, and E) and discriminant analyses of principal components (B, D, and F) of meristic characters between males and females from each island.
Summary statistics of the adjusted morphometric characters for males and females from each island. Abbreviations are in the Materials and methods.
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Mean | 1.93 | 1.47 | 1.16 | 0.97 | 0.77 | 0.95 | 1.27 | 1.38 | 1.13 |
±1 sd | 0.03 | 0.03 | 0.02 | 0.02 | 0.01 | 0.02 | 0.01 | 0.02 | 0.02 |
Minimum | 1.88 | 1.41 | 1.12 | 0.93 | 0.75 | 0.89 | 1.23 | 1.34 | 1.09 |
Maximum | 2.00 | 1.51 | 1.19 | 1.01 | 0.80 | 0.99 | 1.30 | 1.42 | 1.16 |
n | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
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Mean | 1.91 | 1.47 | 1.16 | 0.97 | 0.77 | 0.95 | 1.27 | 1.37 | 1.12 |
±1 sd | 0.03 | 0.02 | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 | 0.02 | 0.02 |
Minimum | 1.88 | 1.42 | 1.14 | 0.94 | 0.74 | 0.94 | 1.24 | 1.34 | 1.07 |
Maximum | 1.99 | 1.50 | 1.18 | 0.99 | 0.78 | 0.98 | 1.28 | 1.39 | 1.14 |
n | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 | 12 |
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Mean | 1.93 | 1.48 | 1.17 | 0.98 | 0.76 | 0.95 | 1.27 | 1.38 | 1.15 |
±1 sd | 0.03 | 0.02 | 0.02 | 0.01 | 0.01 | 0.02 | 0.01 | 0.02 | 0.02 |
Minimum | 1.89 | 1.44 | 1.13 | 0.95 | 0.74 | 0.91 | 1.23 | 1.32 | 1.11 |
Maximum | 1.99 | 1.50 | 1.20 | 1.01 | 0.79 | 0.99 | 1.30 | 1.41 | 1.17 |
n | 37 | 37 | 37 | 37 | 37 | 37 | 37 | 37 | 37 |
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Mean | 1.92 | 1.48 | 1.18 | 0.97 | 0.76 | 0.95 | 1.27 | 1.38 | 1.13 |
±1 sd | 0.03 | 0.01 | 0.02 | 0.01 | 0.01 | 0.02 | 0.01 | 0.01 | 0.02 |
Minimum | 1.86 | 1.44 | 1.13 | 0.95 | 0.74 | 0.91 | 1.24 | 1.35 | 1.07 |
Maximum | 1.96 | 1.50 | 1.20 | 0.99 | 0.80 | 0.99 | 1.30 | 1.40 | 1.17 |
n | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
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Mean | 1.96 | 1.51 | 1.19 | 1.01 | 0.81 | 0.99 | 1.30 | 1.40 | 1.17 |
±1 sd | 0.04 | 0.01 | 0.01 | 0.02 | 0.01 | 0.02 | 0.01 | 0.02 | 0.02 |
Minimum | 1.88 | 1.48 | 1.17 | 0.94 | 0.78 | 0.95 | 1.27 | 1.38 | 1.14 |
Maximum | 2.02 | 1.53 | 1.22 | 1.05 | 0.83 | 1.03 | 1.32 | 1.44 | 1.23 |
n | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
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Mean | 1.94 | 1.51 | 1.20 | 1.01 | 0.80 | 1.00 | 1.29 | 1.41 | 1.16 |
±1 sd | 0.03 | 0.01 | 0.02 | 0.03 | 0.02 | 0.02 | 0.01 | 0.01 | 0.02 |
Minimum | 1.88 | 1.48 | 1.15 | 0.95 | 0.77 | 0.94 | 1.26 | 1.37 | 1.12 |
Maximum | 2.03 | 1.55 | 1.23 | 1.06 | 0.84 | 1.04 | 1.32 | 1.44 | 1.20 |
n | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 | 32 |
Summary statistics for the PCAs of the morphometric characters between the sexes for all island populations. Shaded cells denote characters bearing the highest loadings. Abbreviations are in the Materials and methods.
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Standard deviation | 1.69102 | 1.19550 | 1.04608 | 0.96615 | 0.92217 | 0.85369 | 0.73535 | 0.58753 | 0.46733 |
Proportion of variance | 0.31773 | 0.1588 | 0.12159 | 0.10372 | 0.09449 | 0.08098 | 0.06008 | 0.03835 | 0.02427 |
Cumulative proportion | 0.31773 | 0.47653 | 0.59812 | 0.70183 | 0.79632 | 0.8773 | 0.93738 | 0.97573 | 1 |
Eigenvalue | 2.85955 | 1.42921 | 1.09428 | 0.93344 | 0.85040 | 0.72878 | 0.54075 | 0.34519 | 0.21840 |
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–0.04170 | –0.00296 | –0.67114 | 0.71277 | –0.04750 | 0.18035 | –0.05392 | –0.04386 | –0.01301 |
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–0.39380 | –0.48365 | 0.17609 | 0.06467 | –0.13896 | 0.07244 | –0.35329 | –0.16653 | –0.63143 |
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–0.18974 | 0.59742 | 0.14656 | –0.00647 | –0.51300 | 0.23115 | –0.21042 | –0.46700 | 0.08125 |
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–0.42701 | 0.25634 | 0.26804 | 0.18657 | 0.01194 | 0.36080 | 0.06720 | 0.71408 | –0.02334 |
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–0.27901 | –0.19318 | –0.44067 | –0.55613 | 0.11196 | 0.47275 | –0.23358 | 0.00431 | 0.30128 |
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–0.37182 | 0.03627 | 0.24164 | 0.20921 | 0.66420 | 0.12713 | 0.22999 | –0.47257 | 0.15728 |
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–0.42503 | –0.29438 | 0.09280 | 0.16825 | –0.27118 | –0.48096 | –0.14584 | 0.05380 | 0.60559 |
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–0.25193 | 0.46539 | –0.27478 | –0.14427 | 0.35194 | –0.52069 | –0.40356 | 0.11074 | –0.23135 |
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–0.40575 | 0.03958 | –0.29755 | –0.22530 | –0.25303 | –0.19111 | 0.72932 | –0.06200 | –0.24127 |
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Standard deviation | 1.59879 | 1.26841 | 1.03970 | 0.96864 | 0.92026 | 0.78509 | 0.73735 | 0.65214 | 0.61932 |
Proportion of variance | 0.28402 | 0.17876 | 0.12011 | 0.10425 | 0.0941 | 0.06849 | 0.06041 | 0.04725 | 0.04262 |
Cumulative proportion | 0.28402 | 0.46278 | 0.58289 | 0.68714 | 0.78123 | 0.84972 | 0.91013 | 0.95738 | 1 |
Eigenvalue | 2.55614 | 1.60886 | 1.08097 | 0.93826 | 0.84687 | 0.61637 | 0.54368 | 0.42528 | 0.38356 |
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–0.04292 | 0.02769 | –0.81357 | 0.11408 | –0.54945 | 0.03169 | –0.12149 | 0.06882 | 0.00945 |
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–0.44434 | –0.07742 | 0.05257 | –0.17015 | –0.24620 | –0.55029 | 0.62959 | 0.04986 | 0.05046 |
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–0.47163 | –0.13716 | 0.18281 | 0.33507 | –0.04872 | 0.00500 | –0.36073 | 0.24987 | 0.64660 |
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–0.26039 | –0.38202 | –0.37201 | –0.19276 | 0.51821 | –0.34490 | –0.31792 | –0.34259 | –0.06916 |
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–0.31992 | –0.22811 | –0.03820 | –0.65677 | –0.02707 | 0.61308 | 0.08046 | 0.16703 | 0.04296 |
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–0.38463 | –0.30393 | 0.22019 | 0.40702 | –0.26597 | 0.26869 | –0.01530 | –0.39533 | –0.49607 |
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–0.37658 | 0.46190 | 0.06652 | –0.10542 | 0.05073 | –0.16943 | –0.36567 | 0.44845 | –0.51304 |
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–0.21043 | 0.61169 | 0.06194 | –0.23014 | –0.13959 | 0.04537 | –0.12398 | –0.65217 | 0.25001 |
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–0.27223 | 0.31075 | –0.32454 | 0.38408 | 0.52254 | 0.31364 | 0.44930 | 0.04858 | 0.02891 |
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Standard deviation | 1.55341 | 1.32003 | 1.04910 | 1.00828 | 0.97695 | 0.86045 | 0.68796 | 0.60170 | 0.44392 |
Proportion of variance | 0.26812 | 0.19361 | 0.12229 | 0.11296 | 0.10605 | 0.08226 | 0.05259 | 0.04023 | 0.0219 |
Cumulative proportion | 0.26812 | 0.46173 | 0.58402 | 0.69698 | 0.80303 | 0.88529 | 0.93788 | 0.9781 | 1 |
Eigenvalue | 2.41309 | 1.74249 | 1.10061 | 1.01662 | 0.95443 | 0.74038 | 0.47329 | 0.36204 | 0.19706 |
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–0.01892 | 0.07381 | –0.16493 | 0.80586 | –0.55711 | 0.02425 | –0.06887 | 0.03681 | 0.02296 |
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0.35249 | 0.29690 | –0.02701 | 0.15973 | 0.36469 | 0.62071 | –0.44842 | 0.15948 | 0.12868 |
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0.35843 | –0.11165 | 0.48683 | –0.18608 | –0.46334 | 0.35612 | 0.00173 | –0.38893 | –0.30767 |
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0.40005 | –0.49581 | 0.07878 | 0.17950 | 0.14547 | –0.08116 | 0.15353 | –0.24927 | 0.66502 |
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0.50436 | 0.09166 | –0.26741 | 0.07841 | 0.10880 | 0.07611 | 0.69665 | 0.25127 | –0.30572 |
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0.37677 | –0.44900 | –0.11137 | 0.05868 | 0.08518 | –0.38884 | –0.49867 | 0.19769 | –0.44091 |
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0.24388 | 0.54309 | –0.03576 | 0.13027 | 0.20886 | –0.43466 | –0.07619 | –0.61780 | –0.08544 |
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0.35005 | 0.37398 | 0.16698 | –0.29929 | –0.40071 | –0.32767 | –0.10654 | 0.45112 | 0.37061 |
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0.09239 | –0.05745 | –0.78472 | –0.37696 | –0.31225 | 0.16566 | –0.13943 | –0.26908 | 0.11614 |
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San Clemente vs Santa Barbara | 7.976328842 | 0.112380127 | 0.000119998 | 0.000359993 |
San Clemente vs San Nicolas | 17.8912351 | 0.210754798 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 28.63042077 | 0.330489227 | 2.00E-05 | 6.00E-05 |
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San Clemente vs Santa Barbara | 3.38186634 | 0.074520213 | 0.020819584 | 0.062458751 |
San Clemente vs San Nicolas | 12.35061832 | 0.168377835 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 13.11340086 | 0.242331856 | 2.00E-05 | 6.00E-05 |
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San Clemente vs Santa Barbara | 4.256208897 | 0.063283509 | 0.001919962 | 0.005759885 |
San Clemente vs San Nicolas | 58.34675042 | 0.465482753 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 60.41960349 | 0.510216229 | 2.00E-05 | 6.00E-05 |
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San Clemente vs Santa Barbara | 2.961345004 | 0.065864244 | 0.008879822 | 0.026639467 |
San Clemente vs San Nicolas | 66.56440768 | 0.521810189 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 46.06328362 | 0.52907818 | 2.00E-05 | 6.00E-05 |
Sex Concatenated Data | F statistic | R1 | p value | p adjusted |
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San Clemente vs Santa Barbara | 5.50039433 | 0.080297265 | 2.00E-05 | 6.00E-05 |
San Clemente vs San Nicolas | 41.91324325 | 0.384831468 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 47.10026177 | 0.448145999 | 2.00E-05 | 6.00E-05 |
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San Clemente vs Santa Barbara | 3.20096222 | 0.070816241 | 0.002359953 | 0.007079858 |
San Clemente vs San Nicolas | 40.67761809 | 0.400064624 | 2.00E-05 | 6.00E-05 |
Santa Barbara vs San Nicolas | 31.24682525 | 0.432501015 | 2.00E-05 | 6.00E-05 |
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M = male; F = female | ||||
San ClementeM |
3.20096222 | 0.070816241 | 0.001679966 | 0.025199496 |
San ClementeM |
40.67761809 | 0.400064624 | 2.00E-05 | 0.000299994 |
San ClementeM |
3.646344679 | 0.05161406 | 0.000539989 | 0.008099838 |
San ClementeM |
6.155707548 | 0.095949492 | 2.00E-05 | 0.000299994 |
San ClementeM |
48.90634901 | 0.440969786 | 2.00E-05 | 0.000299994 |
Santa BarbaraM |
31.24682525 | 0.432501015 | 2.00E-05 | 0.000299994 |
Santa BarbaraM |
4.747560753 | 0.091744629 | 8.00E-05 | 0.001199976 |
Santa BarbaraM |
1.147106447 | 0.029302458 | 0.334293314 | 1 |
Santa BarbaraM |
35.92059215 | 0.460989722 | 2.00E-05 | 0.000299994 |
San NicolasM |
34.79306543 | 0.345193048 | 2.00E-05 | 0.000299994 |
San NicolasM |
41.35669936 | 0.42047669 | 2.00E-05 | 0.000299994 |
San NicolasM vs San NicolasF | 1.897946171 | 0.03017501 | 0.054378912 | 0.815683686 |
San ClementeF |
5.50039433 | 0.080297265 | 2.00E-05 | 0.000299994 |
San ClementeF |
41.91324325 | 0.384831468 | 2.00E-05 | 0.000299994 |
Santa BarbaraF |
47.10026177 | 0.448145999 | 2.00E-05 | 0.000299994 |
Using an
Principal component analyses (A, C, and E) and discriminant analyses of principal components (B, D, and F) of morphometric characters between males and females from each island.
Summary statistics of the meristic characters for males and females from each island. Abbreviations are in the Materials and methods.
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Mean | 34.30 | 50.96 | 5.19 | 10.57 | 23.38 |
sd | 1.08 | 2.81 | 0.94 | 0.79 | 0.91 |
Minimum | 32 | 45 | 3 | 9 | 22 |
Maximum | 36 | 57 | 7 | 12 | 25 |
n | 28 | 28 | 28 | 28 | 28 |
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Mean | 34 | 50.91 | 5.08 | 10.75 | 22.92 |
sd | 1.21 | 2.35 | 0.79 | 0.45 | 1 |
Minimum | 32 | 45 | 4 | 10 | 22 |
Maximum | 36 | 54 | 6 | 11 | 25 |
n | 12 | 12 | 12 | 12 | 12 |
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Mean | 33.51 | 48.43 | 4.78 | 10.35 | 22.68 |
sd | 0.93 | 2.24 | 0.82 | 0.82 | 1.18 |
Minimum | 32 | 43 | 3 | 8 | 20 |
Maximum | 36 | 52 | 7 | 13 | 25 |
N | 37 | 37 | 37 | 37 | 37 |
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Mean | 33.34 | 48.63 | 5.59 | 10.81 | 22.31 |
Sd | 0.83 | 2.55 | 1.01 | 0.54 | 1.18 |
Minimum | 31 | 43 | 4 | 10 | 20 |
Maximum | 35 | 55 | 7 | 12 | 25 |
n | 32 | 32 | 32 | 32 | 32 |
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Mean | 33.06 | 43.63 | 4.28 | 10.63 | 21.59 |
sd | 1.05 | 2.12 | 0.96 | 0.71 | 1.41 |
Minimum | 31 | 38 | 3 | 9 | 19 |
Maximum | 35 | 47 | 6 | 12 | 24 |
n | 32 | 32 | 32 | 32 | 32 |
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Mean | 32.90 | 45.06 | 4.94 | 10.61 | 21.45 |
Sd | 1.16 | 2.45 | 0.77 | 0.99 | 1.34 |
Minimum | 31 | 40 | 4 | 9 | 19 |
Maximum | 35 | 51 | 7 | 13 | 25 |
n | 31 | 31 | 31 | 31 | 31 |
Summary statistics for the PCAs of the meristic characters between the sexes for all island populations. Shaded cells denote characters bearing the highest loadings. Abbreviations are in the Materials and methods.
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Standard deviation | 1.35020 | 1.06599 | 0.90096 | 0.80562 | 0.76149 |
Proportion of variance | 0.36461 | 0.22727 | 0.16235 | 0.1298 | 0.11597 |
Cumulative Proportion | 0.36461 | 0.59188 | 0.75422 | 0.88403 | 1 |
Eigenvalue | 1.82304 | 1.13634 | 0.81174 | 0.64902 | 0.57987 |
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–0.55376 | 0.08801 | –0.32068 | –0.39447 | 0.65358 |
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–0.47302 | –0.45275 | 0.21901 | –0.49266 | –0.52971 |
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–0.49439 | –0.29215 | 0.39941 | 0.67806 | 0.22568 |
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0.16313 | –0.71739 | –0.65114 | 0.18451 | 0.02669 |
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–0.44562 | 0.43274 | –0.51545 | 0.32843 | –0.49052 |
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Standard deviation | 1.23114 | 1.11417 | 0.91322 | 0.85415 | 0.82424 |
Proportion of variance | 0.30314 | 0.24828 | 0.16680 | 0.14591 | 0.13588 |
Cumulative Proportion | 0.30314 | 0.55142 | 0.71821 | 0.86412 | 1.00000 |
Eigenvalue | 1.51570 | 1.24138 | 0.83398 | 0.72957 | 0.67938 |
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–0.51197 | 0.24144 | –0.62982 | 0.38195 | 0.37018 |
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–0.52228 | –0.14062 | 0.66328 | 0.51605 | –0.03458 |
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0.02325 | –0.72012 | –0.39511 | 0.30278 | –0.48281 |
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–0.37543 | –0.57778 | 0.03169 | –0.54629 | 0.47517 |
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–0.56888 | 0.26370 | –0.07919 | –0.44463 | –0.63473 |
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Standard deviation | 1.35766 | 0.97754 | 0.94659 | 0.82394 | 0.79136 |
Proportion of variance | 0.36865 | 0.19112 | 0.17921 | 0.13578 | 0.12525 |
Cumulative Proportion | 0.36865 | 0.55977 | 0.73897 | 0.87475 | 1.00000 |
Eigenvalue | 1.84324 | 0.95558 | 0.89604 | 0.67888 | 0.62626 |
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0.50525 | –0.20941 | 0.30917 | –0.65894 | 0.41362 |
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0.50567 | –0.31369 | 0.08704 | 0.73085 | 0.32276 |
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–0.36679 | –0.60275 | –0.57665 | –0.11135 | 0.39651 |
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0.33892 | 0.61644 | –0.63488 | –0.03456 | 0.31759 |
Using ANCOVA analyses with size-corrected
(A) Principal component analysis, (B) discriminant analyses of principal components, and (C) comparative violin plots with embedded boxplots of morphometric characters among females from each island showing the range, frequency, mean (white dot), and 50% quartile (black rectangle) for each character. Violin plots are vertically oriented mirror-imaged frequency diagrams.
Principal component analyses (
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SN-SC | 0.009 | 0 | 1.43E-05 | 0 | 0 | 0 | 5.95E-07 | 0 | 1.83E-07 |
SB-SC | 0.011 | ||||||||
SB-SN | 0.021 | 7.59E-08 | 1.65E-08 | 4.01E-09 | 0 | 1.06E-07 | 2.27E-07 | 9.29E-10 | 1.03E-08 |
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SN-SC | 3.000463e-07 | 2.00E-07 | 9.58E-06 | 7.59E-09 | 4.84E-10 | 5.15E-10 | 8.69E-10 | 4.09E-08 | 3.00E-07 |
SB-SC | 0 | ||||||||
SB-SN | 4.837105e-10 | 2.25E-09 | 4.84E-10 | 5.26E-10 | 4.84E-10 | 6.35E-09 | 6.21E-10 | 3.99E-07 | 4.84E-10 |
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SN-SC | 1.62E-01 | 4.85E-10 | 8.84E-04 | ||||||
SB-SC | 8.60E-03 | 1.52E-04 | 6.41E-02 | ||||||
SB-SN | 3.11E-05 | 4.84E-10 | 0.0007 | 4.07E-07 | |||||
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SN-SC | 7.31E-07 | 0.012 | 0.018 | ||||||
SB-SC | 2.14E-02 | ||||||||
SB-SN | 0.0078 | 4.10E-09 | 0.002 |
Using an
(A) Principal component analysis, (B), discriminant analyses of principal components, and (C) comparative boxplots of meristic characters among females from each island showing the range, mean (blue dot), and 50% quartile (rectangle) for each character. White dots are y-axis values.
Principal component analyses (
Comparisons of
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log-transformation of morphometric data | |
Size correction of log-transformed morphometric data using geometric means | size-correction of raw morphometric data using the GroupStruct equation |
Size correction of meristic data presumably using geometric means | raw meristic data untreated |
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Student |
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ANCOVA on log-transformed morphometric data and meristic data with island and sex as factors and size-corrected log-transformed |
two-way |
MANOVA including all islands | |
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MANOVA on log-transformed morphometric | one-way |
MANOVA on size-corrected log-transformed morphometric for each sex | |
Pillai’s Trace (V) calculated from MANOVA to estimate the effect size of the factors island, subspecies, and sex. | this analysis was not done |
MANOVA on size-corrected meristic data corrected for each sex | one-way |
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LDA of log-transformed morphometric data for each sex | this analysis was not done |
LDA of size-corrected log-transformed morphometric data for each sex. | this analysis was not done |
Conducting ANCOVAs on the size-corrected meristic data set using the size-corrected
Principal component analyses (A and C) and discriminant analyses of principal components (B and D) of the concatenated morphometric and meristic data sets of females and males from each island.
Principal component analyses (
(A) Principal component analysis, (B) discriminant analyses of principal components, and (C) comparative violin plots with embedded boxplots of morphometric characters among males from each island showing the range, frequency, mean (white dot), and 50% quartile (black rectangle) for each character.
Using an
(A) principal component analysis, (B) discriminant analyses of principal components, and (C) comparative boxplots of meristic characters among males from each island showing the range, mean (blue dot), and 50% quartile (rectangle) for each character. White dots are y-axis values.
Conducting ANCOVAs on the size-corrected meristic data set using the size-corrected
Principal component analyses (
Principal component analysis (A) and discriminant analysis of principal components (B) of concatenated morphometric and meristic characters with combined sexes from each island.
Principal component analyses (
Differences between the results of
Our data indicate that the majority of overall morphological variation among the three island populations is reflected in body shape (Figs
We presume that based on their log-transformed data corrected for size,
Our data demonstrated that lizards from the San Nicolas island population had relatively longer limbs than those from the other two islands. Many studies have shown that shorter limbs are more advantageous for locomoting through restrictive types of vegetation (e.g.
We thank Nicole E. Adams and Gregory B. Pauly for sharing the raw data upon which this paper was written. We thank them and William J. Mautz for sending us literature. We are grateful for the comments of Robert Fisher, Brad Hollingsworth, and Diego Arenas-Moreno and one anonymous reviewer. We are grateful to Charles A. Drost for many insightful conversations and emails regarding the natural history of Island night lizards. We thank Nicholas A. Hess for providing photographs of lizards from Santa Barbara Island.