In the aftermath of the Cretaceous-Tertiary (K/T) boundary event it appears that unusual phytoplankton blooms were boosted by the abundant nutrient levels left over from a short-lived "Strangelove Ocean' period, which possibly gave rise to the negative-to-positive δ13C surface-to-bottom gradient in the Danian. The highly plastic morphology of the planktonic foraminifera at the base of the Palaeocene appeared, most likely, as an adaptive response of functional morphology to the pelagic habitat of the species and its mode of life. The diversification episodes of Danian planktonic foraminifera appear to correspond to times of reduced oceanic mixing, stratified water masses, recovery of the surface water productivity and a progressive expansion of the trophic-resource continuum, with periods of maximum diversity corresponding to widespread oceanic surface-water oligotrophic conditions. A revised phylogeny is suggested for the early Palaeocene planktonic foraminifera based on recorded stratigraphic ranges and morphological affinities. -from Author