And during the transitional stage between quadrupedal and bipedal stance, there is plenty of variation.

在四足和双足姿势之间的过渡阶段，有很多变化。

So old grandpa turtle seemed to mark a kind of transitional stage between Eunotosaurus, with its wider ribs, and Odontochelys, with its full plastron.

这么老的龟爷爷似乎标志着一种过渡阶段，介于具有更宽肋骨的真诺龙和具有完整腹甲的齿甲龟之间。

It was this rafting that acted as a transitional  stage in their huge ecological shift, allowing them to establish an evolutionary foothold  in their new, much harsher environment.

正是这次漂流充当了它们巨大的生态转变的过渡阶段，使它们能够在新的、更加恶劣的环境中建立进化的立足点。