Data associated with: Global ecomorphological restructuring of dominant marine reptiles prior to the K/Pg mass extinction

Mosasaurid squamates were the dominant amniote predators in marine
ecosystems during most of the Late Cretaceous. Here, we use a suite of
biomechanically rooted, functionally descriptive ratios in a framework
adapted from population ecology to investigate how the morphofunctional
disparity of mosasaurids evolved prior to the Cretaceous-Paleogene (K/Pg)
mass extinction. Our results suggest that taxonomic turnover in mosasaurid
community composition from Campanian to Maastrichtian is reflected by a
notable global increase in morphofunctional disparity, especially driven
the North American record. Ecomorphospace occupation becomes polarised
during the Late Maastrichtian, with morphofunctional disparity plateauing
in the Southern Hemisphere and decreasing in the Northern Hemisphere. We
show that these changes are not strongly associated with mosasaurid size,
but rather with the functional capacities of their skulls. Our novel
approach indicates that mosasaurid morphofunctional disparity was in
decline in multiple provincial communities before the K-Pg mass
extinction, highlighting region-specific patterns of disparity evolution
and the importance of assessing vertebrate extinctions both globally and
locally. Ecomorphological differentiation in mosasaurid communities,
coupled with declines in other formerly abundant marine reptile groups,
indicates widespread restructuring of higher trophic levels in marine food
webs was well underway when the K/Pg mass extinction took place.