Tuesday, December 04, 2012

Angiosperms' Rise to Dominance in Cretaceous Europe

Rise to dominance of angiosperm pioneers in European Cretaceous environments


1. Clément Coiffard (a)
2. Bernard Gomez (b,*)
3. Véronique Daviero-Gomez (b)
4. David L. Dilcher (c,*)


a. Museum für Naturkunde, Leibniz Institut für Evolutions und Biodiversitätsforschung, Invalidenstrasse 43, D-10115 Berlin, Germany

b. Centre National de la Recherche Scientifique Unité Mixte de Recherche 5276, Laboratoire de Géologie de Lyon–Terre, Planètes, Environnement, Université Lyon 1 (Claude Bernard), F-69622 Villeurbanne Cedex, France

c. Department of Geology, Indiana University, Bloomington, IN 47405-7005

*. To whom correspondence may be addressed. E-mail: dilcher@indiana.edu or bernard.gomez@univ-lyon1.fr.


The majority of environments are dominated by flowering plants today, but it is uncertain how this dominance originated. This increase in angiosperm diversity happened during the Cretaceous period (ca. 145–65 Ma) and led to replacement and often extinction of gymnosperms and ferns. We propose a scenario for the rise to dominance of the angiosperms from the Barremian (ca. 130 Ma) to the Campanian (ca. 84 Ma) based on the European megafossil plant record. These megafossil data demonstrate that angiosperms migrated into new environments in three phases: (i) Barremian (ca. 130–125 Ma) freshwater lake-related wetlands; (ii) Aptian–Albian (ca. 125–100 Ma) understory floodplains (excluding levees and back swamps); and (iii) Cenomanian–Campanian (ca. 100–84 Ma) natural levees, back swamps, and coastal swamps. This scenario allows for the measured evolution of angiosperms in time and space synthesizing changes in the physical environment with concomitant changes in the biological environment. This view of angiosperm radiation in three phases reconciles previous scenarios based on the North American record. The Cretaceous plant record that can be observed in Europe is exceptional in many ways. (i) Angiosperms are well preserved from the Barremian to the Maastrichtian (ca. 65 Ma). (ii) Deposits are well constrained and dated stratigraphically. (iii) They encompass a full range of environments. (iv) European paleobotany provides many detailed studies of Cretaceous floras for analysis. These factors make a robust dataset for the study of angiosperm evolution from the Barremian to the Campanian that can be traced through various ecosystems and related to other plant groups occupying the same niches.

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