One hundred million years later, the warm, shallow seas were packed with tiny plants and animals — essentially, hors d'oeuvres for a plethora of bigger creatures like trilobites, conodonts, brachiopods, and corals.

一千万年之后，温暖的浅海充满了微小的植物和动物——基本上是大量大型生物的胃菜，如同三叶虫，牙形虫，腕足类和珊瑚。

Throughout their history, conodonts were affected by several mass extinctions, including the Great Dying at the end of the Permian Period 252 million years ago.

在整个历史上， 牙形石受到几次大绝的影响，包括2.52亿年前二叠纪末期的“大绝” 。

Species like conodonts, ammonoids, crinoids and green algae suffered particularly  high extinction rates during the CPE, as did reef builders.

在卡尼期洪积事件期间， 诸如牙形石、菊石、海百合和绿藻等物种遭受了特别高的绝率，珊瑚礁建造者亦未能幸免。

For instance, you know when the Devonian Period ends and the Carboniferous Period begins, because that's when you start finding fossils that belong to a species of conodont known as Siphonodella sulcata.

例如， 你知道泥盆纪结束石炭纪始，因为始发现属于一种名为Siphonodella sulcata的牙形石物种的化石。

It was only marginally more fish-like than its earlier relatives, hagfish and conodonts, with which it shared a common ancestor.

它仅比其早期的亲戚——七鳃鳗和锥齿动物——稍微多一点像鱼，它们共享一个共同祖先。

And the fossils also revealed that the tiny, tooth-like conodont elements were concentrated in the animal's mouth -- but also in its throat!

而且这些化石还揭示了，些类似牙齿的牙形石元素集中在动物的口腔中——但也出现在它的喉咙里！

But while paleontologists were spending a hundred years or so debating what conodonts were, geologists were discovering what conodonts could do.

但是， 当古生物学家花了大约一百年的间争论什么是牙形刺，地质学家正在发现牙形刺的作用。

And conodonts were all of those things -- abundant, widespread, and composed of lots of distinctive species.

牙形石就是所有这些——数量丰富，分布广泛， 并且由许多独特的物种组成。

It turns out that conodont elements actually change color when they're heated up.

原来，牙形石元素在加热实际上会变色。

In the 1970s, fossils of some vaguely fish-like creatures were found in Montana that were thought to be conodont animals.

20世纪70年代，在蒙大拿州发现了一些类似鱼类的生物化石，人们认为这些是牙形石动物。

Check out " The Most Useful Fossils in  the World" , to learn more about conodonts.

查看《世界上最实用的化石》，了解更多关于牙形石的知识。

Likewise, in the Triassic Period, nearly every age is defined by the first appearance of various conodonts.

同样，在三叠纪期，几乎每个年代都是由各种牙形石的首次出现来定义的。

So it turned out that they weren't conodont animals; they were fossils of creatures that ate conodont animals!

原来它们并不是牙形石动物；它们是吃牙形石动物的生物的化石！

But further study revealed that the conodont elements found in those fossils were actually in the animals' guts.

但进一步的研究表明，些化石中发现的牙形石实际上是在动物的肠道里。

But meanwhile, paleontologists still had no idea what kind of animals conodonts were.

但与此同，古生物学家仍然不知道牙形石属于哪种动物。

Like modern lampreys and hagfish, conodonts were jawless fish, and they were one of the earliest and most successful groups of vertebrates.

像现代的七鳃鳗和盲鳗一样， 牙形石是无颌鱼类，它们是最早也是最成功的脊椎动物群之一。

But conodont elements can do more than just that!

但牙形石元素不仅仅能做这些！

So they were given the name conodont, which means " cone tooth." These elements are all verrry tiny.

所以它们被命名为牙形石，意思是“锥形牙齿”。这些元素都非常非常小。

Thanks to these beautiful specimens, we were able to learn that conodont animals were a kind of fish after all!

感谢这些美丽的标本，我们得以了解到牙形石动物终究是一种鱼！

So conodont elements quickly became one of the handiest tools in the geologist toolkit.

因此，牙形石元素很快成为地质学家工具箱中最有用的工具之一。