What is a shared derived character or synapomorphy of pachycephalosaurs?

什么是厚头龙的共同衍生特征或联结形态？

Although pachycephalosaurs have all of these features, it is only the thicken, domed skull that all pachycephalosaurs share.

尽管厚头龙具有所有这些特征，但所有厚头龙共有的只是加厚的圆顶头骨。

We now believe pachycephalosaurs used their head both as a formidable weapon and as a colorful display.

我们现在相信厚头龙既把头部当成可怕的武器，也当成五彩斑斓的展示品。

The most distinctive feature about the pachycephalosaurs, of course, is this really weird dome that they have on their head.

肿头龙最显著的特征，当然是它们头上那个非常奇怪的圆顶。

The Pachycephalosaur headbutting theory suggests that two rival pachycephalosaurs may have charged head-long into one another and collided skull dome to skull dome.

Pachycephalosaur headbutting 理论表明，两只竞争的 pachycephalosaurs 可能已经冲向彼此，头骨穹顶与头骨穹顶相撞。

They went back and looked through historic museum collections and discovered that actually there was quite a lot of evidence for these lesions in a similar place across a whole bunch of different pachycephalosaurs.

于是人们回头去检查历史博物馆里的藏品，发现其实有很多化石存在这样的损伤，遍布众多肿头龙当中的类似部位。