For example, the skull of a placoderm had an internal braincase made of endoskeletal bone.

例如，盾动物的头骨有一个由内骨骼骨制成的内部脑壳。

While the placoderms were conquering the seas, things were getting even more crowded on land.

当盾服海洋时， 陆地上的东西变得更加拥挤。

And heterostracans, osteostracans and placoderms have been found in both salty AND fresh water environments.

在咸水和淡水环境中都发现了 heterostracans、osteostracans 和 placoderms。

And scientists have seen signs of those changes in the armor of heterostracans, osteostracans and placoderms.

科学家们已经看到了异类动物、骨类动物和盾动物的盔发生这些变化的迹象。

In some placoderms, the covering got up to 5 centimeters thick.

在一些盾动物中，覆物厚达 5 厘米。

But it's not clear how armored fish, especially placoderms, were related to either of these groups.

但尚不清楚，尤其是盾，与这两个群体有何关系。

Now, one of the most widespread placoderms was Bothriolepis, which was able to live in oceanic environments, estuaries, and freshwater settings.

现在，分布最广的盾动物之一是 Bothriolepis，它能够生活在海洋环境、河口和淡水环境中。

So armored fish came in a variety of shapes and sizes during the Silurian and Devonian, from tiny Heterostracans to massive Placoderms.

因此，在志留纪和泥盆纪期间， 的形状和大小各不相同，从微小的异类到巨大的盾。

While the eurypterines were busy competing with fish, stylonurines moved inland, to brackish and freshwater ecosystems where there were fewer placoderms and less competition.

当广翅鳍忙于与竞争时，苯丁则向内陆移动， 进入咸水和淡水生态系统， 那里的盾动物较少， 竞争也较少。

So, we probably have placoderms to thank for the nightmare fuel that followed, a family of giant eurypterines that persisted for nearly 40 million years.

因此， 我们可能要感谢盾动物为随后的噩梦提供了燃料，这是一个持续了近 4000 万年的巨型广翅目动物家族。

But as the Silurian gave way to the Devonian, a dangerous new competitive pressure entered the seas — the armored, jawed fish known as the placoderms.

但随着志留纪让位给泥盆纪，一种危险的新竞争压力进入了海洋——被称为盾的有有颚。

But placoderms were also unique among armored fish in having a complete, mineralized internal skeleton – meaning they had both an endoskeleton, like you do, as well as an exoskeleton.

但盾在有中也是独一无二的，因为它们拥有完整的、矿化的内部骨骼——这意味着它们既有内骨骼，就像你一样， 也有外骨骼。

Others think that most placoderms specifically share common ancestors with ray-finned and lobe-finned fishes, but there are some placoderms that are more closely related to lobe-finned fishes than to other armored fish.

其他人认为大多数盾与辐鳍和叶鳍有共同的祖先，但也有一些盾与叶鳍的关系比与其他的关系更密切。

In the Late Devonian, giant armored jawed fish -- the placoderms -- would come to dominate these seas and force other ocean-dwellers to adapt, flee, or perish.

在泥盆纪晚期，巨大的有颚——盾——将主宰这些海洋并迫使其他海洋生物适应、逃离或灭亡。

But despite their best efforts, these invertebrates couldn't keep up with placoderms, and eurypterines lost over 50 percent of their diversity within the first 10 million years of the Devonian.

但是，尽管他们尽了最大努力， 这些无脊椎动物还是赶不上盾动物，而广翅目动物在泥盆纪的前 1000 万年内失去了超过 50% 的多样性。

But the eurypterines that did survive managed to stage a sort of evolutionary rally, getting bigger, faster, and stronger in the Devonian to cope with seas filled with placoderms that were doing the same.

但是，幸存下来的广翅目动物成功地进行了一场进化集会，在泥盆纪变得更大、更快、更强壮， 以应对充满同样做同样事情的盾动物的海洋。