Scientists believe this early time in motility may have faced a setback soon after the Paleoproterozoic Era, about the time of the Gabon fossils.

科学家们认为，这种早期的活性可能在古元古代（大约是加蓬化石年代）后不久就开倒退。

Primitive ungulates survived and grew after the K-Pg Extinction thanks  to evolutionary innovations like specialized teeth for chewing and grinding vegetation.

原有物在卡罗来纳-古元古代灭绝之后幸存下来并繁衍，这要归功于诸如用于咀嚼和磨碎植物的专门牙齿等进化创新。

And this may have happened more than once in the late Proterozoic.

而这 在晚元古代可能不止一次过。

Nuna existed from 1.8 to 1.4 billion years ago, in the middle of the Proterozoic Eon.

努纳存在于 1.8 到 14 亿 年前，在元古代纪元中期。