Webbing
Unlike spines, sails are fleshy and soft, made of stretched skin and able to be moved an maneuvered. Especially common in aquatic species, sails and their variants are a newly recognized mutation.
Sails often can also display as webbing between existing spines, if spines are present on the body in an area where the sail would develop.
Fleshy webbing, either between limbs or between fingers. This can be transluscent or opaque.
Mycelium is a mutation where strange fungal growths appear to come off of the body of a colonist. The example above is just that: an example of one of the ways the mutation can appear, with both holes and growths. If you want just holes or just growths, it is up to you. It can go on any portion of the body and it can fade into a maximum of two unnatural colours plus speckles.
Oftentimes, the growths will have little speckles or will glow slightly in the dark.
Tsabhua Example Lineart: here.
