Data from: Cope’s rule and the adaptive landscape of dinosaur body size evolution
Data files
Aug 30, 2018 version files 10.72 MB
-
Appendix S1.docx
258.21 KB
-
Appendix S2 SURFACE regime configurations.zip
3.40 MB
-
Appendix S3 cross plotting of regime configurations.zip
2.14 MB
-
Appendix S4 pBIC and AICc SURFACE search trajectories.zip
2.70 MB
-
Appendix S5 phenograms.zip
873.60 KB
-
Dataset S1.zip
398.04 KB
-
Dataset S2 dinosaur trend model fits Benson 2017.xlsx
198.51 KB
-
Dataset S3 OU results.xlsx
87.80 KB
-
Phylogenetic trees Benson 2017.zip
321.65 KB
-
Scripts S1.zip
22.32 KB
Abstract
The largest known dinosaurs weighed at least 20 million times as much as the smallest, indicating exceptional phenotypic divergence. Previous studies have focused on extreme giant sizes, tests of Cope's rule, and miniaturization on the line leading to birds. We use non-uniform macroevolutionary models based on Ornstein–Uhlenbeck and trend processes to unify these observations, asking: what patterns of evolutionary rates, directionality and constraint explain the diversification of dinosaur body mass? We find that dinosaur evolution is constrained by attraction to discrete body size optima that undergo rare, but abrupt, evolutionary shifts. This model explains both the rarity of multi-lineage directional trends, and the occurrence of abrupt directional excursions during the origins of groups such as tiny pygostylian birds and giant sauropods. Most expansion of trait space results from rare, constraint-breaking innovations in just a small number of lineages. These lineages shifted rapidly into novel regions of trait space, occasionally to small sizes, but most often to large or giant sizes. As with Cenozoic mammals, intermediate body sizes were typically attained only transiently by lineages on a trajectory from small to large size. This demonstrates that bimodality in the macroevolutionary adaptive landscape for land vertebrates has existed for more than 200 million years.