sp. indet.

例句：

1. 1. The sp.indet. is a mysterious creature that has been found in the jungle.
   这个不明生物在丛林中被发现。
2. 2. The sp. indet. is a rare species of bird that can be found only in certain regions.
   这个不明物种的鸟只在特定地区发现。
3. 3. The sp. indet.is a fascinating animal that has never been seen by humans before.
   这个不明动物令人着迷，之前从未被人类见过。