There are about 30 members of the genus Icosidesmus in New Zealand. Many species are yet to be described. All are similar to I. variegatus in shape and size but colour patterns vary from a relatively uniform gold, reddish-brown, or greenish-brown, to patterns of brown and cream. As in most millipedes a defensive secretion is released from pores on the side of the keel-like projections on the side of the body units. This secretion is white in these millipedes but in others it can be bright red, yellow or brown. It stains the hands and stinks, thus putting off any predator hoping for a tasty morsel. I. variegatus has a close relative I. schenkeli that is endemic to Banks Peninsula and another, I. falcatus that is widely distributed from North Canterbury to the Marlborough Sounds.
All species have distinct distribution patterns like the ones shown here and shown with Icosidesmus montanus. I. schenkeli is confined to the dry, western portion of Banks Peninsula and the wetter, eastern portion has an undescribed species.