- It is the cuticle that suggests rotifers are close relatives of roundworms and arthropods.
- The Cambrian Explosion, for example, is the first time we are able to distinguish a chordate from an arthropod.
- The ecdysozoans are supposed to include arthropods, priapulids and nematodes.
- All chelicerate arthropods have this special first set of modified legs.
- It is of interest that a plant native to Eurasia would host such substantial numbers of phytophagous arthropods in North America.