这些部分的特征让古生物学家得以作出这样的结论：这种动物在哺乳动物谱系中，与有胎盘类的关系较与有袋类(如袋鼠)的关系更接近。

These features led the paleontologists to conclude that the animal was closer to living placentals on the mammalian family tree than to pouched marsupials, such as kangaroos.

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之后的五千万年内没有任何新奇的事发生，就在这时，胎盘哺乳动物(或者说是那些有后代存活的哺乳动物)突然之间分化为四种所谓的生物总目。

Nothing much then happened for 50m years when, all of a sudden, the placentals (or, at least, those with surviving descendants) split into four so-called superorders.

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