TABLE 1. Results of model comparison for Cryptolithus tesselatus. Numbers in parentheses = set breakpoints for each threshold model; bolded values indicate best supported model. Better support is indicated by lower AICc values. AICc weights indicate the relative likelihood of each model; these are normalized to sum to 1 and may be interpreted as probabilities. See text for additional explanation of different models, and Figure 6 and Figure 9 for plots showing different model fits and slopes for the best supported model.

  3D landmarks 2D landmarks
  AICc AICc weights AICc AICc weights
linear model -114.9327 0.0010 -120.283 0.0239
threshold model 1 (early shift) -128.2149 0.7439 -126.9374 0.6663
threshold model 2 (late shift) -118.9646 0.0073 -122.6766 0.0792
threshold model 3 (two shifts) -126.0163 0.2478 -124.815 0.2306

 

TABLE 2. Results of model comparison for Marrolithus bureaui (data from Delabroye and Crônier, 2008). See Table 1 for explanation of AICc values, text for explanation of different models, and Figure 10.1 for plot showing linear model and best supported threshold model. Values in parentheses are the natural log of centroid size for breakpoints in each model.

  AICc AICc weights
linear model -356.065 0.0008
threshold model 1 (1.85) -356.665 0.0010
threshold model 2 (2.5) -362.037 0.0153
threshold model 3 (2.8) -369.57 0.6618
threshold model 4 (two shifts) -368.123 0.3211

 

TABLE 3. Results of model comparison for seven additional species. See Table 1 for explanation of AICc values, text for explanation of different models, and Figure 10.2-8 for plots showing linear model and best supported threshold model, set breakpoints, and data sources.

  AICc AICc weights
  linear model threshold model linear model threshold model
Aulacopleura koninckii -1678.252 -1678.6962 0.4447 0.5553
Triarthrus becki -501.786 -598.3558 0.0000 1.0000
Zacanthopsis palmeri -686.7376 -760.1803 0.0000 1.0000
Haniwa quadrata -400.8708 -440.5485 0.0000 1.0000
Liostracina tangwangzhaiensis -234.3299 -239.6435 0.0656 0.9344
Apatokephalus latilimbatus -398.1783 -396.8969 0.6549 0.3451
Olenellus gilberti -532.0049 -553.5915 0.0000 1.0000