There are two forms of locomotion in dinosaurs, there is bipedal and quadrupedal.

恐龙的运动方式有两种，两足运动和四足运动。

Pachyrhinosaurus though was a more compact quadrupedal kind of animal, a more sturdy build than what we see in Albertosaurus.

肿鼻角龙是一种更结实的四足动物，比阿尔伯特龙身体更加粗壮。

So, quadrupedal dinosaurs evolved from bipedal ones.

所以，四足恐龙是从两足恐龙进化而来的。

So little Scleromochlus appears to be a bipedal, ancestral cousin of a quadrupedal group.

如此小的 Scleromochlus 似乎是四足类群的两足类远亲。

Did pterosaurs come from bipedal, running ancestors, or quadrupedal ancestors that lived in trees?

翼龙是来自两足、奔跑的祖先，还是生活在树上的四足祖先？

Tooth shape, bipedal or quadrupedal, number of holes behind the eye in the skull, and so on.

牙齿形状、双足或四足、头骨中眼睛后面的孔数等。

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。

Before we get into bipedal and quadrupedal dinosaurs lets think again about a group of animals, mainly humans.

在我们进入双足和四足恐龙之前，让我们再想想一群动物，主要是人类。

There's actually lots of evidence to suggest that, even if their ancestors were bipedal, pterosaurs themselves were quadrupedal.

实际上有很多证据表明，即使它们的祖先是双足的，翼龙本身也是四足的。

Humans change their stance from quadrupedal babies, to bipedal adults.

人类将他们的姿势从四足婴儿转变为双足成人。