Lower molar area ratios plotted for 132 mammalian genera, with regression line. The black line represents the IC Model as predicted by Kavanagh et al. , with the white areas representing the predicted possible areas under the strict IC Model. Grey regions are outside the predicted areas of the model, and represent regions of the graph where m2 is either the largest lower molar (bottom-right) or the smallest (top-left). 65.2% of sampled taxa fall within the predicted area. The thin red line is the reduced major axis regression line, with 95% confidence bands in blue on either side.