Tail-Walking Mudhopper
The Tail-Walking Mudhopper split from its ancestor and moved further inland, losing its old habits of hunting in the ocean in favor of the low-competition environment known as dry land. It retains its amphibious and burrowing habits, but it has become less dependent on water by improving its air respiration and outright losing its gills. It has developed more armor for muscle attachment, and its armor has a keratinous covering to protect it. The keratinous cover sheds periodically to allow growth, much like the exoskeletons of many Terran arthropods except that the main hard structure—the bone—remains underneath. Its most notable change, however, is that it has developed the ability to walk—with its tail!
The development of a “tail-leg” allows the Tail-Walking Mudhopper to move about on land with far more efficiency, and it grants it additional speed. This is vital for catching its primary prey, Wortopedes, which would otherwise be too fast for it. It mainly hunts at night, when the air is cool and moist. If not for its need to return to water to soak or reproduce, it would be fully terrestrial. Like its ancestor, it may fight with others of its kind over their burrows, usually interlocking tentacles until one backs off.
The Tail-Walking Mudhopper has adjusted its respiration somewhat. No longer using its chamber for flotation, it was able to specialize it even more for breathing air. The armor covering it is almost entirely keratinous with only rib-like bones remaining as the original bony armor, allowing it to expand to breath more actively, like a lung. It has developed more openings along the side of the chamber, which reduces the likelihood that all of them will be plugged up with mud at a given time. It mainly eats Wortopedes, as mentioned before, but will feed on Twistworms and Ghost Mycostrums when available.
Like its ancestor, it has internal fertilization and lays hundreds of eggs per mating. Its babies are fully aquatic and depend on detritus, but they live in the rivers and streams instead of in the ocean. Babies retain gills, but they are absorbed in adulthood. Adults are poor swimmers due to the changes to the tail.