Perhaps the chordate crowd, with their notochords, segmented muscles and big bony skeletons.

或许是脊，有脊，分节肌肉和干瘪大骨架。

The major groups of animals we see around us today -- from sponges to arthropods to chordates -- all showed up in this little window of time in the Cambrian.

我们今天在我们周围看到的主要群——从海绵到节肢再到脊——都出现在寒武纪的这小时间窗口。

Most of the main groups of the animal kingdom—arthropods, brachiopods, coelenterates, echinoderms, molluscs and even chordates, the branch from which vertebrates went on to develop—are found in the fossil beds of the Cambrian.

人们在寒武纪群落里发现了王国的主要集群，包括腕足、腔肠、棘皮、软体和脊（脊椎进化的分支）。

It's called a Pikaia and it's a little wormlike creature but it's thought that this is a chordate, and that is the branch of life that we're in, so it could that this is our earliest known ancestor.

叫皮卡虫，确实和普通虫子差不多，不过人们认为是一种脊，也就是说，和我们是同一类，所以这也许是我们最早的祖先了。

Simple as it was, this was one of the earliest chordates -- part of the family that would give rise to the vertebrates and includes us, making us cousins over 500 million years removed.

尽管很简单， 但这是最早的脊之一——属于脊椎家族的一部分， 包括我们在内，使我们相隔 5 亿年成为远亲。