The earliest armored fish we have fossils of is called Sacabambaspis, a member of the subclass known as Arandaspida.

我们拥有化石的最早的装甲鱼被称为 Sacabambaspis，它是 Arandaspida 亚纲的成员。

And this is where armored fish start to take an especially interesting turn.

这就是装甲鱼开始发生特别有趣的转变的地方。

And this brings us to probably the best-known armored fish, the Placoderms.

这让我们想到了可能是最著名的铠甲鱼——盾皮鱼。

So, it seems that these armored fish did use their bony armor for mineral storage.

所以，这些铠甲鱼似乎确实用它们的骨质铠甲来储存矿物质。

Whatever the cause, armor was no protection against the effects of it, and so the armored fish disappeared.

不管是什么原因， 盔甲都无法抵御它的影响，所以盔甲鱼消失了。

Some scientists think that, while both ray-finned and lobe-finned fish shared common ancestors with armored fish, they aren't their direct descendants.

一些科学家认为， 虽然辐鳍鱼和叶鳍鱼与铠鱼有共同的祖先，但它们不是它们的直系后代。

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， 装甲鱼的形状和大小各不相同，从微小的异类鱼到巨大的盾皮鱼。

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

但尚不清楚装甲鱼，尤其是盾皮鱼，与这两个群体有何关系。

The problem is that, like so many things in paleontology, the relationship of armored fish to other living things is … vague.

问题是，就像古生物学中的许多事物一样，装甲鱼与其他生物的关系是… … 模糊的。

And indeed, bite marks on armored bone, and remnants of armored fish found in the feces of other animals, are common in the fossil record.

事实上， 装甲骨上的咬痕，以及在其他动物粪便中发现的装甲鱼残留物，在化石记录中都很常见。

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.

但盾皮鱼在有甲鱼中也是独一无二的，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。

The late Devonian is characterized by one of Earth's " big 5" mass extinctions, with a loss of 50 to 60% of marine genera, including all of the armored fish.

泥盆纪晚期的特点是地球“5 大” 物种大灭绝之一，50% 到 60% 的海洋物种消失，包括所有的铠甲鱼。

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皮鱼与辐鳍鱼和叶鳍鱼有共同的祖先，但也有一些盾皮鱼与叶鳍鱼的关系比与其他装甲鱼的关系更密切。