Resumen de Test ultrastructure of the problematic microfossil Bicornifera Lagaaiji Keij from the Gulf Coastal Plain Oligocene

Kenneth L. Finger, George L. Armstrong, Richard E. Marolt, Drew Haman

• The wall structure of the problematic microfossil Bicornifera lagaaiji Keij 1977 is redescribed based on thin-section analysis of specimens from the Byram Marl of Mississippi. The wall is not radial as previously described, but appears to be trilamellid, composed of a middle cryptocrystalline layer bounded on both sides by thin sheetlike calcite crystals oriented with the c-axis oblique to the test surface.