Data from: The megaherbivore gap after the non-avian dinosaur extinctions modified trait evolution and diversification of tropical palms

The Cretaceous–Paleogene (K-Pg) extinction of the non-avian dinosaurs (66
Ma) led to a 25 million year gap of megaherbivores (>1000 kg)
before the evolution of megaherbivorous mammals in the Late Eocene (40
Ma). The botanical consequences of this ‘Paleocene megaherbivore gap’
(PMHG) remain poorly explored. We hypothesize that the absence of
megaherbivores should result in changes in the diversification and trait
evolution of associated plant lineages. We used phylogenetic time- and
trait-dependent diversification models with palms (Arecaceae) and show
that the PMHG was characterized by speciation slowdowns, decreased
evolution of armature, and increased evolution of megafaunal (≥4cm)
fruits. This suggests that the absence of browsing by megaherbivores
during the PMHG may have led to a loss of defence traits, but absence of
megaherbivorous seed dispersers did not lead to a loss of megafaunal
fruits. Instead, increases in PMHG fruit sizes may be explained by Late
Paleocene rising temperatures, rainforest expansion, and the subsequent
radiation of seed dispersing birds and mammals. We show that the profound
impact of the PMHG on plant diversification can be detected even with the
overwriting of adaptations by the subsequent Late Eocene opening-up of
megaherbivore-associated ecological opportunities. Our study provides a
quantitative, comparative framework to assess diversification and
adaptation during one of the most enigmatic periods in angiosperm history.