By the Late Cretaceous, therizinosaurs took these adaptations one step further.

到白垩纪晚期，镰刀龙在这些适应性上又向前迈进了一步。

So how and why did the therizinosaurs end up looking so different from their cousins?

那么，镰刀龙是如何以及为什么最终看起来与它们的表亲如此不同的呢？

It shows an in-between phase between therizinosaurs and their more carnivorous ancestors.

它显示了镰刀龙与其更食肉的祖先之间的中间阶段。

Falcarius was much smaller than other therizinosaurs, weighing around 100 kg.

镰刀龙比其他镰刀龙小得多，重约 100 公斤。

This would mean that the therizinosaurs went from omnivory to herbivory, and were never carnivorous at all!

这意味着镰刀龙从杂食性转变为食草性，并且根本不是肉食性的！

Therizinosaurs that lived in the same place at the same time even became more specialized to avoid competition with each other!

同时生活在同一个地方的镰刀龙甚至变得更加专业化，以避免相互竞争！

But the mystery didn't end there… Because how the therizinosaurs lived and evolved ended up being just as weird as their mixed-up anatomy.

但谜团并没有就此结束… … 因为镰刀龙的生活和进化方式最终和它们混乱的解剖结构一样奇怪。

So, amid all of this competition, the therizinosaurs were pushed into their weird combination of features to carve out their own ecological niche.

因此，在所有这些竞争中，镰刀龙被推向了它们奇怪的特征组合，以开辟自己的生态位。

From their initial mistaken identity as giant-clawed turtles, to the debates about how they evolved, the therizinosaurs have been surprising paleontologists for decades.

从它们最初被误认为是巨爪龟，到关于它们如何进化的争论，几十年来， 镰刀龙一直让古生物学家感到惊讶。

And the specific adaptations of the therizinosaurs – like long necks and claws – probably also helped them avoid competition with other herbivorous dinosaurs, like hadrosaurs and ceratopsians.

镰刀龙的特殊适应性——比如长长的脖子和爪子——可能也帮助它们避免与其他食草恐龙竞争，比如鸭嘴龙和角龙。

The second scenario pointed out that these two groups and the therizinosaurs belong to a specific subgroup of theropods called Coelurosauria, along with dedicated carnivores like T. rex.

第二种情况指出，这两个种群和镰刀龙属于兽脚类动物的一个特定亚群，称为虚骨龙，以及像霸王龙这样的专职食肉动物。

And this is the group that includes birds, along with a whole variety of other theropods, like the Therizinosaurs with those enormous hand claws, and none other than T. rex.

这是一个包括鸟类在内的群体，还有其他各种兽脚类动物，比如长着巨大手爪的镰刀龙，霸王龙就是其中之一。