Actinoceras

例句：

1. 1.Actinoceras is a type of fossil found in the Cretaceous period.
   阿特纳克斯虫是一种在白垩纪时期发现的化石。
2. 2.The discovery of Actinoceras has sparked debate about its significance in Earth's history.
   阿特纳克斯虫的发现引发了关于其在地球历史中重要性的辩论。
3. 3. Researchers have been studying Actinoceras for decades, hoping to unlock new insights into the planet's past.
   研究人员已经研究了阿特纳克斯虫几十年，希望揭开星球过去的秘密。