Piercing Gastroworms
With the oceans filled to the brim with life, the geletaventrian coproworm had an entire buffet of hosts everywhere it went. While it stayed as one species for a while, eventually they became successful enough to rapidly diversify into a large genus.
A prominent feature of piercing gastroworms are the two large, stiff horns on the sides of their head. These horns are modified to dig into the intestinal walls of their hosts, making them nearly impossible to pull out. Additional spines on the body also help with this, letting the whole organism stay firmly anchored. Their mouths have developed into a sharp point, allowing them a liquivorous lifestyle. While they are still able to break down fecal matter using their digestive enzymes, their main method of getting food is to pierce the lining of the intestine in order to suck the host’s blood using their small teardrop-shaped mouth.
While some gastroworms keep the ancestral sucker on their posterior end, in many species it has been modified into a bilateral fin for propulsion, and in a few species it has withered away into a vestigial tube-like structure. Species with a fin-like appendage usually parasitize faster hosts, letting the microscopic larvae of the gastroworm quickly find a suitable individual. In order to have a higher chance of sexual reproduction, most species are able to release a pheromone that attracts other gastroworms. The gastroworm’s chemoreceptors are more sensitive, allowing them to seek out new hosts from birth and detect pheromones from mature worms.
Like their ancestor, piercing gastroworms come in a wide variety of sizes to accommodate different hosts. While many species still depend on geletaventrians, some have begun to infect asterzoan hosts. Certain species that infect large devorators such as filter chads can greatly exceed their species’ average lengths due to the nearly infinite amount of nutrition they have access to.