沟鞭藻的起源:分子地球化学证据

沟鞭藻为单细胞的原始的海洋生物。古生物学家根据形态特征，超微结构和生物化学信息认为沟鞭藻可能在前寒武纪时已存在，并推测古生代疑源类可能是现代沟鞭藻的先祖，但确凿的沟鞭藻囊孢的化石记录始于晚三叠世。生物标志物以分子化石的形式记录了沟鞭藻的起源及演化历史。在古生代及前寒武纪地层中甲藻甾烷及三芳沟鞭藻的检出，建立了沟鞭藻与其古代先祖（疑源类）的联系，提供了沟鞭藻先祖前寒武纪存在的证据。

THE ORIGIN OF DINOFLAGELLATES: MOLECULAR GEOCHEMICAL EVIDENCE

Dinoflagellates are single-celled and primitive marine organisms. It was considered that dinoflagellates may be present in the Precambrian, and perhaps some Acritarches are the ancestors of modern dinoflagellates on the basis of morphological, ultrastructural, and biochemical information, but undisputed fossil dinoflagellate cysts was not recorded in rocks older than Late Triassic. Biomarker, as molecular fossil, recorded the origin and evolutionary history of dinoflagellate. The presence of dinosteroids and triaromatic dinosteroids in the Precambrian formation provides compelling evidence that dinoflagellate ancestors exist during Precambrian.