Foreword.-Introduction -- Chapter 1 Biofaciological zonation of recent benthic foraminifera along a tropical Pacific Colombian shelf-to-slope bathymetric gradient -- Chapter 2 Modern benthic foraminifera of the Panamá Bight -- Chapter 3 Late Pleistocene paleoenvironmental and paleoclimatic changes in southern Buenos Aires province, Argentina -- Chapter 4 Turonian Danian Zonation -- Chapter 5 Turonian Santonian Zonation -- Chapter 6 Calcareous microfossils of the MIS 1 in its innermost sector, Rio Salado Basin -- Chapter 7 Danian calcareous microfossils from Ombucta x-1 well, Colorado Basin, Argentina -- Chapter 8 Late Miocene foraminifera and ostracoda, from Cajon valley, Catamarca, Argentina -- Chapter 9 A new microfaunistic record from the Late Quaternary of Salinas del Bebedero, San Luis, Argentina -- Chapter 10 Late Cretaceous – Cenozoic Biostratigraphy and Palaeoenvironmental reconstruction of the Salado and Punta del Este Basins, Argentine continental margin -- Conclusion -- References. .This book offers many examples of calcareous microfossils and describes a new microfaunistic record in Argentina. These selected papers of the 11th Argentine Paleontological Congress include micropaleontological studies on material of different geological ages from several sites in Argentina and Colombia. The authors highlight several geological findings and explain the paleoenvironmental changes in Argentina and Colombia.