Spinal Keratin
Hard keratinous growths along the spine of the colonist.
Bony spines grow along the spine of a colonist. These can be fairly short and stubby or long and thin and can be in either one line down the spine or two along either side. These should be no wider than the eye. Spines are widest at the base, where they attach to the body, and they narrow until they reach the tip.
One large spine sprouts along the midsection of the colonist's back, like a spinosaurus.
Similar to a stegosaurus with upright plates running down its spine. These can either be one row or a pair of rows on either side of the spinal cord. They should be more than simple bumps and tend to extend out a bit.
