The extinction of Metapolygnathus parvus marks the end of the Carnian, for example, while the start of the Rhaetian is defined by the first appearance of the genus Misikella.

Metapolygnathus parvus 绝标志着 Carnian 结， 例如，而 Rhaetian 开始 Misikella 首次出现定义。