Fig. 4. Niche occupancy dynamics before and after the end-Cretaceous mass extinction.

Boxplots show the distribution of the log-scaled species marginality (A) and tolerance (B) for each trophic group across the latest Cretaceous (Campanian: yellow; Maastrichtian: green) and early Paleogene (Danian: blue). The lower the species marginality (i.e., niche position), the less different its habitat preferences are from the average paleoenvironmental conditions. The higher the species tolerance (i.e., niche breadth), the more widely a species occurs across broad paleoenvironmental ranges. Boxplot bold lines indicate the median, whereas the boxes and whiskers are the interquartile range (IQR) and the maximum and minimum up to 1.5× IQR, respectively. Silhouettes and abbreviations of representative animals follow Fig. 2 and were obtained from http://phylopic.org/ (see Acknowledgments).