Beneath the surface, 在水面下方

163. that has remained almost the same for hundreds of millions of years.
     已经保持了数亿年 几乎不变
164. And yet, living in the same prehistoric swamps,
     然而在同一片史前沼泽之中
165. another group of animals were undergoing their own radical change.
     另一群动物正在经历巨变
166. Beneath the surface,
     在水面下方
167. vertebrates had continued to evolve...
     脊椎动物继续进化
168. and a new type of fish was thriving,
     一种新型鱼类蓬勃发展
169. the lobe-finned fish.
     叶鳍鱼

来自《我们星球上的生命 第一季 第三集 Life on Our Planet S01E03 入侵大地》第 166 行