Flowers in space? An angiosperm-wide morphospace study based on extant taxa, fossils, and ancestral reconstructions

Marion Chartier, Anna Maria Louise von Balthazar-Schönenberger, Hervé Sauquet, Jürg Schönenberger

Morphospaces are mathematical descriptions used for studying the evolution of morphological diversity (disparity) and for the evaluation of realized shapes and trait combinations among theoretically possible ones in groups of extinct and extant taxa. A common approach includes the calculation of disparity indexes that allow to quantify and compare morphological diversity among groups. In addition, reduced (2- or 3-dimensional) space representations can be built, where similar morphologies fall close to each other. Although widely used in zoology, morphospaces ? with few exceptions ? have been neglected in plant science in general and in the study of broad-scale patterns of floral structure and evolution in particular. Here, we build an angiosperm-wide floral morphospace, using the currently largest dataset on floral morphology (Sauquet et al. 2017, Nat. Comm.), which contains data for almost 800 species of angiosperms. We add fossil flowers to this data, and unravel the position of extant and extinct angiosperms (realized forms) in the theoretical morphospace (theoretical forms). Furthermore, we depict the relative positions of all major angiosperm clades in the space, showing a mosaic pattern of space occupation, and calculate the relative contribution of major clades to overall disparity. In their paper, Sauquet et al. used model-based reconstruction methods to infer the floral morphology of the most recent common ancestor (MRCA) of all angiosperms and its early descendants and thereby developed a new scenario for the early evolution and diversification of flowers. In addition to extant flowers and fossils, we also place the reconstructed ancestral flowers of a series of major (deep) nodes in the angiosperm phylogeny (e.g., MRCRs of mesangiosperms, monocots, eudicots, etc.) in the morphospace. Our analyses reveal possible starting points and subsequent trajectories taken by different angiosperm clades in the morphospace during the course of their evolution.

Department of Botany and Biodiversity Research
External organisation(s)
Université Paris XI - Paris-Sud, National Herbarium of New South Wales
Publication date
Austrian Fields of Science 2012
106042 Systematic botany, 106008 Botany, 106012 Evolutionary research
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