Wormback
The Wormback is a small, neotenic, worm-like descendant of the Golden Notback. It very closely resembles a juvenile Notback, apart from coloration. It lives most of its life underground, using its short but broad clawed legs to burrow and using its little tentacles, still covered in tiny teeth, to pull bits of dead flora and fauna into its mouth. As a result, it is a very important part of the ecosystem and contributes greatly to soil formation. It is only 15 cm long, a size decrease it was able to achieve because there were no other primarily-burrowing fauna in its niche.
The Wormback needed little change apart from its neoteny to adapt to life underground. Having hemerythrin as its blood pigment, it was already set to thrive in low-oxygen conditions. Still, its eyes are reduced. It retains its ears, which alert it to rain, prompting it to return to the surface. As it is an active air-breather, it would drown if it did not.
Like its ancestor, the Wormback has an exoskeleton consisting of two layers—bone and keratin. The bone layer grows with the Wormback, while the protective keratin layer, being keratin, must be periodically shed. It is generally solitary, though it will meet others of its kind to mate. Fights are rare compared to its ancestor, though when they occur they are usually between males over mating rights. They lay their soft-shelled eggs in deep or well-shaded dirt as they burrow along, the soil around them naturally keeping the eggs as moist as they need to be.