But what does all of this mean for our lineage of mammaliaforms, the crown mammals?

但是，所有这一切对我们的哺乳动物谱系（皇冠哺乳动物）意味着什么呢？

But what about that fourth classic crown mammal trait: lactation?

但是第四个经典的皇冠哺乳动物特征是什么：哺乳？

So that's us, plus our extinct relatives outside crown mammals.

这就是我们，加上我们已灭绝的皇冠哺乳动物以外的亲戚。

In crown mammals, these bones are completely detached from the mandible and are part of the three-boned middle ear.

在有冠哺乳动物中，这些骨头完全脱离下颌骨，是三骨中耳的一部分。

But it's possible that crown mammals weren't the first or only ones to evolve this set up.

但有可能皇冠哺乳动物不是第一个或唯一进化出这种结构的哺乳动物。

And if it could suckle, then it probably lactated and fed its young with milk, just like all crown mammals do.

如果它可以哺乳， 那么它可能会泌乳并用牛奶喂养它的后代，就像所有皇冠哺乳动物一样。

So, a lot of traits that we think of as being unique to crown mammals actually evolved earlier, in various different mammaliaforms.

因此，许多我们认为是皇冠哺乳动物独有的特征实际上更早以各种不同的哺乳动物形式进化。

If we trace these guys back to their most recent common ancestor with crown mammals, we end up with a group known as the mammaliaforms.

如果我们将这些家伙追溯到它们最近与皇冠哺乳动物的共同祖先，我们最终会得到一个被称为哺乳动物的类群。

This is a trait that's shared among other mammaliaforms, and it's this feature that typically separates Morganucodon and mammaliaforms like it from the crown mammals.

这是其他哺乳动物共有的特征，正是这个特征通常将 Morganucodon 和类似的哺乳动物与皇冠哺乳动物区分开来。

So, while the Age of Mammals only really got going when the Mesozoic ended, it's worth remembering that our success as crown mammals started much, much earlier.

因此， 虽然哺乳动物时代在中生代结束时才真正开始，但值得记住的是， 我们作为皇冠哺乳动物的成功开始得非常非常早。

Today, it's relatively easy to take a living animal and figure out if it's a true mammal, because all crown mammals have these four things in common.

今天， 拿一只活的动物来判断它是否是真正的哺乳动物相对容易，因为所有皇冠哺乳动物都有这四个共同点。

And one reason this trait might've been important for early mammaliaforms and then for the first crown mammals is that many of them were small insectivores who probably hunted at night.

这种特性可能对早期哺乳动物很重要，然后对第一个皇冠哺乳动物很重要的一个原因是，它们中的许多都是小型食虫动物，可能在夜间捕食。