selenodont

例句：

1. 1. This selenodont is a rare species that has been extinct for over 65 million years.
   这种无颌类动物是一种罕见的物种，已经灭绝了超过6500万年。
2. 2. The discovery of this selenodont fossil has shed new light on the evolution of our ancestors.
   这种无颌类动物化石的发现为我们祖先的进化提供了新的见解。
3. 3. Due to its unique features, this selenodont was once considered a separate order of animals.
   由于其独特的特征，这种无颌类动物曾被认为属于一个独立的动物纲。