Fossil Discovery Adds Another Phylum to the Cambrian Explosion

The Cambrian explosion just got a bit more explosive with the discovery of a likely member of phylum Kinorhyncha from rocks in South China that are about 530 million years old. If you've never heard of kinorhynch worms, also called "mud dragons," that's probably because they are very tiny, seldom discussed, and found living only in certain marine environments around the world. As the Encyclopedia of Life explains:

Around 150 species of kinorhynchs have been described since this group was firs...