Anoculopha
Anoculophs are a class of Tarates which evolved certain features distinctly from the rest of that phylum. Distantly related, they are not technical vertebrates in the sense of having a spine, but they instead have a more "primitive" system that is supported by a hollow cartilaginous tube that acts as a backbone.
Description
Anoculophs are Tarates with a cartilaginous dorsal support chord and chitins growths on the body.