Dinoflagellates are single-celled organisms that reflect the ecological conditions in modern oceans and Lakes. Ultrastructural data and molecular phylogeny suggest that they originated in the Neoproterozoic, yet dinoflagellate ancestors are classified only to the Middle Triassic (similar to 240 million years ago). Examination of dinoflagellate-specific biological markers (dinosteranes and 4 alpha-methyl-24-ethylcholestane) in concentrated microfossils with known morphology identified ancient dinoflagellate ancestors from the Early Cambrian (similar to 520 million years ago).