Carapacer

The Carapacer split off from its ancestor and became an obligate crystal-eater. As crystals contain a lot of mineralized matter, it has developed a carapace covered in keratin which has a bone-like core to store all the excess. This carapace doubles as partial protection from predators. Its digestive system has advanced, and it now digests the melter detritis in its gut using stomach acid rather than absorbing them into its cells directly. It has also evolved a blood pigment; as its circulatory system is derived from the same organ as its stomach it is also inevitably slightly acidic, so it uses vanadium chromagen, carried in specialized cells called vanadocytes, which functions very well in these acidic conditions; as a side effect, it is incapable of evolving to not incidentally secrete stomach acid into its circulatory system, as this particular blood pigment does not function without it.

The Carapacer has lost the webbing between its anal fingers and converted them into three long tentacle-like “tails”. This makes it much easier to hold on while mating, enhancing reproductive success. Due to the development of the carapace, the carapacer’s hatching is delayed until it begins to form after the body has already differentiated into its adult proportions where the carapace won’t be in the way as it develops; as a result, its offspring are already bilateral when they hatch. To support this greater development time, more yolk is provided in each egg; as this takes more energy but results in larger healthier offspring which are more likely to survive, the Carapacer lays fewer eggs at a time, often only 10-15 per mating.

The Carapacer is otherwise much like its ancestor. It uses melter detritis obtained from its environment to digest the crystal flora it consumes and then in turn digests the melter detritis, much like a real-world ruminant.