Functional and historical drivers of leaf shape evolution in palms (Arecaceae)

Abstract

AimLeaves display a remarkable variety of shapes, each with potential ecological advantages in specific climates. While the relations between leaf shape and either climate or height have been relatively well studied in eudicots, the macroecological drivers of shape remain poorly known in monocots. Here, we investigated the associations between climate and plant height with the evolution of leaf shape in a clade with high species and morphological diversity.LocationGlobal.Time periodCretaceous to contemporary.Major taxa studiedPalms (Arecaceae).MethodsWe apply a Bayesian phylogenetic mixed model to test for associations between climate and leaf shape (all – entire‐leaved, pinnate‐dissected, palmate‐dissected and costapalmate). We further reconstruct the ancestral leaf shape using multistate speciation and extinction models and compare the frequency of shapes with global temperatures through time.ResultsWe find that plant height associates with dissected leaves and that annual precipitation associates with pinnate shapes. The ancestral leaf shape is unclear, but early diversification was dominated by pinnate‐dissected palms, which has remained the most species‐rich form of leaves throughout palm history.Main ConclusionsPalms that are tall and live in humid regions are more likely to have pinnate leaves. Through geological time scales, temperature did not play an obvious role in determining leaf shapes. This study contributes to our understanding of how the diversity of leaf shapes is linked to biological and climatic factors.

Early Cretaceous Origin and Evolutionary History of Palms (Arecaceae) inferred from 1,033 Nuclear Genes and a New Synthesis of Fossil Evidence

“…This study not only provided the foundations on which a new phylogenetic classification of palms was built (Dransfield et al, 2008) but also led to much downstream evolutionary research (e.g. : Antonelli et al, 2017; Cássia-Silva et al, 2019; Faurby et al, 2016; Onstein et al, 2017; Torres Jiménez et al, 2023). However, the classification of palms has subsequently evolved, with some genera split, others merged and new ones discovered as new-to-science (Baker & Dransfield, 2016; Eiserhardt et al, 2022; Hodel et al, 2021; Pérez-Calle, Bellot et al, 2024; Sâm et al, 2023), rendering the existing synthesis incomplete.…”