Arachnopods

Arachnopods constitute many of the terrestrial ukfauna, which have internal skeletons, handed tails, and four clawed limbs around their faces.

Evolution
The first multicellular progenitor of the Ukfauna, a minuscule predator by the name of Uksip Hydroidea, lays down the basis for most of Ukfauna physiology for the next several million years. The tiny predator had highly developed digestive and muscular systems, while the rest of its physiology remained quite primordial. Two tentacles, used to ensnare prey, and an anchoring tail were the result of a relatively complex musculature, supported by a fledgling nervous system. The digestive system is fascinating in the fact that the stomach, though unable to digest solids, is attached directly to the hollow tooth, exposing captured prey directly to corrosive gastric acids, allowing nutrients to be absorbed in liquid form. Also of note are the rows of cilia in perfect radial symmetry on the body, and two primordial light-sensing organs by the tooth. The respiratory system at this point is simple diffusion of oxygen in water through a porous skin.

The next major advancement in Ukfauna physiology comes millions of years later, in the form of Uksip Krilliformes. Important developments include the beginnings of more advanced movement systems, namely the flattening of the tail previously used for anchoring, and what is proposed to be a primordial second set of tentacles. The ocular organs, primitive eyes, changed locations to the superior and inferior sides of the head, allowing simultaneous sight in air and water should the Uksip surface. Chitinous stingers at the ends of the tentacles signal two things - the development of a venom glands, probably divergent to the digestive system, and a change in feeding behaviour. Evidence for this also lies in the shortening and widening of the tooth, which is no longer used to wound prey.