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 标志着 Carnian 结， 例如，而 Rhaetian 开 Misikella 属首次出现定义。