Cretaceous charophytes and Palaeocene larger foraminifera are facies-linked microfossils used to perform
biostratigraphic correlation between distant basins, in Eurasia (charophytes) or the whole Tethys (larger
foraminifera). The capability of these organisms for dispersal and colonization is analysed and appears to
be dependent both on palaeoecological and palaeobiological factors. During the Cretaceous of the Northern
hemisphere, Clavatoracean charophytes include five cosmopolitan or subcosmopolitan species. They display
a generalistic range of habitats (from fluvial siliciclastic to alkaline lacustrine and brackish) and conjoint
gametangia (monoecious) allowing them to colonize effectively new sites and disperse. Palaeocene Tethyan
larger foraminifera that show a large distribution live in the deeper parts of shallow platforms, a habitat
where the taxonomic diversity within the group is low. Significant for the long range geographic expansion
of larger foraminifera is the possibility to catch planktonic algae to establish the species-specific
endosymbiosis that characterize the group. In spite of being so different, both case-studies suggest that
there are common patterns of biogeographic behaviour of this kind of facies-linked microfossils, which
could lead to propose a model of biogeographic constraints in long distance biostratigraphic correlation