Twistworms
Twistworms split off and developed some features that allowed them to diversify into a widespread genus. They are named for the fact that adults are twisted—each segment is rotated compared to the previous one, maximizing potential sunlight capture. They have also developed pheromones, which allow young males to locate females to mate with even in dry regions where their populations are sparse. They are also less dependent on mucus to travel; young males are able to extend themselves more like a worm or a caterpillar, bracing themselves against short thorns, to travel more effectively without wasting as much water. These features allowed Twistworms to cross deserts and mountains, populating every region of the Wright continental grouping except for Fermi and the islands.
Across their range, there are many, many species of Twistworm, far too many to list individually. They have a number of general trends based on where they reside. Most species, such as in most plains, mixed, and forest biomes, retain a general stem shape and typically have leaf-shaped thorns. Polar and montane species tend to be stocky and hardy with needle-like thorns. Desert dwellers also have needle-like thorns, and tend to be quite rotund for the sake of water storage. Young males, meanwhile, hardly vary between species; the most notable distinction is that polar and montane males are stockier, much like the adult females in those same regions.
Like their ancestor, Twistworms are sequential hermaphrodites—they are male as juveniles, and female as adults. Adult females are sessile and hold onto the ground with long thorns, while young males crawl around and are detritivorous. Both perform photosynthesis, and adult females collect rainwater with their funnel-like mouthparts. Males also have a pair of pigment cup eyes on each segment. Their behavior is very simple, and when they reach about 1/4 their adult length they plant themselves, change gender, reabsorb their eyes and nervous system, develop the adult funnel-mouth, and begin to grow more segments. At this phase, the segments twist around as they increase in number, giving Twistworms their name. Young males take in female gametes through their spiracles and fertilize them, but as they don’t leave as much of a mucus trail they instead incubate the zygotes inside their spiracles until the baby Twistworms, drawn to sunlight, simply crawl out on their own.