Gastrovermiformes

Gastrovermiformes is an order of worm-like organisms in the phylum Anchyruria who cling to larger organisms for both food and transportation, either clinging around the waste vent or living within a host's guts. Defining features of this branch include a thinner exoskeleton, the ability to use asexual reproduction, and a suction cup at their rear end used to maintain their grip.

Family Coprophagovermidae
The most basal group of Gastrovermiformes, this branch contains members that still live outside of a host and feed on feces, being communalistic in habits.

Family Gastrovermidae
A group of Gastrovermiformes specialized to live within the guts of their hosts, members of this branch are parasitic in habits and possess sharp spines along their segments to hook into the guts of the large creature they live inside of.