他提出一个假说，说那些骨头属于一种已绝种的爬行动物。

He put forward the hypothesis that the bones belonged to an extinct type of reptile.

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树袋熊已列为澳大利亚濒临绝种的动物之一。

The koala is listed among Australia's endangered animals.

《牛津词典》

即使新的种群属于不同物种，它也可以大致填补已灭绝种群空出的生态位，保持食物网的完整。

Even if the new population is of a different species, it can approximately fill the niche vacated by the extinct population and keep the food web intact.

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