But, scientist Elizabeth Sibert says there were other important species as well.

但是，科学家伊丽莎白西伯特说还有其他重要的物种。

Ms. Sibert is a graduate student at the University of California, San Diego.

西伯特女士是加州大学圣地亚哥分校的研究生。

Elizabeth Sibert says her next step is to go back to the micro-fossil record.

Elizabeth Sibert 说她的下一步是回到微化石记录。