Resumen de El registro fósil y la evolución de los vegetales acuáticos continentales del Mesozoico: una síntesis
Palaeobotany applied to freshwater plants is an emerging field of palaeontology. Hydrophytic plants reveal evolutionary trends of their own, clearly distinct from those of terrestrial and marineflora. Between the Silurian and Early Cretaceous, charophytes dominated the macrophytic associations, with the consequence that over dozens of millions of years, the non-marine flora bypassed the evolution and dominance of vascular plants on land. During the Early Cretaceous, global extension of the freshwater environments resulted in a renovation of the benthic and planktonicnon-marine flora. This includes the appearance of the first aquatic angiosperms and ferns along with new charophyte families. In the Late Cretaceous, freshwater angiosperms dominated almostall macrophytic communities worldwide, as they do now. Mesozoic planktonic assemblages keptalso an ancestral physiognomy during most of the Palaeozoic and Mesozoic and were dominated by green algae, mainly Chlorococcales. In the Early Cretaceous non-marine dinoflagellates firstcolonized these planktonic assemblages. The evolution of the freshwater flora is thus characterised by the permanence of a few, long-lasting groups such as benthic charophytes or planktonic chlorococcales, which are living fossils. In contrast, groups originated in terrestrial or marine habitats needed a long time to colonize non-marine environments. Once they entered this environment they showed as well a slow evolutionary rate.
