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Palaios 22 (2007) 200-211
Pierre Moissette ( ) 1, Efterpi Koskeridou 2, Jean-Jacques Cornée 1, Françoise Guillocheau 3, Christophe Lecuyer 1, 4

An exceptionally well-preserved fossil seagrass community occurs in the late Pliocene of the Greek Island of Rhodes. The siliciclastic deposits of the Kritika section (Kritika Member, Rhodes Formation) contain several beds of clay and fine-grained sand with abundant remains of the leaves of Posidonia oceanica. A coarser sand bed with in situ rhizomes of the same endemic Mediterranean phanerogam also was found. Samples yield a diverse skeletal assemblage of 121 species of crustose coralline algae, foraminifers, annelids, gastropods, bivalves, encrusting bryozoans, and ostracodes, some of which also live exclusively on the leaves of present-day P. oceanica. The community of organisms associated with the rhizomes is slightly poorer (57 species), with bivalves appearing as distinctively abundant components of this assemblage (21 species). An analysis of the relationships between skeletal organisms and fossil leaves and rhizomes shows that the majority of them lived together in the same seagrassvegetated environment, were transported a short distance from their natural habitat, and buried very rapidly in fine-grained sediments, thus preserving this remarkable assemblage almost intact. The rhizomes were preserved in growth position within a coarse-grained sand trapped by their horizontal and vertical network. The fossil assemblage compares well in terms of major skeletal components with modern shallow-water P. oceanica meadows. This study also provides evidence for the presence during the Pliocene of an already well-established and widespread seagrass community with biotopes comparable to those of the present-day Mediterranean.
1 :  Paléoenvironnement et paléobiosphère (PP)
CNRS : UMR5125 – INSU – Université Claude Bernard - Lyon I (UCBL)
2 :  Department of Historical Geology-Paleontology, University of Athens
National Technical University of Athens
3 :  Géosciences Rennes (GR)
CNRS : UMR6118 – INSU – Centre Armoricain de Recherches en Environnement – Université de Rennes 1
4 :  Institut Universitaire de France (IUF)
Ministère de l'Enseignement Supérieur et de la Recherche Scientifique
Planète et Univers/Sciences de la Terre/Paléontologie

Planète et Univers/Sciences de la Terre/Océanographie

Sciences du Vivant/Biologie animale/Zoologie des invertébrés

Sciences du Vivant/Ecologie, Environnement/Ecosystèmes

Sciences de l'environnement/Biodiversité et Ecologie

Sciences de l'environnement/Milieux et Changements globaux