Puddleface wormoss originally clung close to the coast, but its descendants have been able to move westward. The life cycle remains similar; an immobile adult sporophyte produces spores, which grow into tiny gametozoons, which mate and produce mobile juvenile sporophytes, which grow into the immobile adults.
The biggest change comes in the gametozoons' lifestyle. After rain, when the sporophyte adults' faces fill with water, they release their spores directly into their face puddles, where they develop into soft, unsegmented wormy swimmers. The gametozoon tissue corresponds largely to the inner core, but they contain nodes of shell cells in their reproductive organs. They remain there until a juvenile of their own species or a young wormwort comes to drink from the puddle. The gametozoon then enters its body through the mouth or a spiracle. It exists as a parasite there, though even for the wormwort, it's a fairly beneficial arrangement in exchange for providing the puddles to drink from. Once the host drinks from another puddle, the gametozoons get together to mate and lay eggs, to be excreted by their host. These eggs now hatch into a juvenile sporophyte.
The juveniles' bodies are much like their ancestors, with a soft inner core containing a digestive tract and with four overlapping segments of photosynthetic shell. With their crushing mandibles, they can eat a wider variety of food too, including crunching leaf-thorns off their wormwort cousins. They are still water-breathers, who must enter water to oxygenate their hemolymph. However, they can store oxygen in their bodies to use over most of a day. They do best in areas with high rainfall, where the adults' rain-catching faces will fill to become puddles. In dry spells, when the faces dry up, the juveniles may rely on streams, but they can also enter a semi-dormant state in which they still photosynthesize but don't move around. Even so, the juvenile stage is quite short, typically a few weeks, enough time to range around to find a spot to burrow.
On burrowing, they develop into an adult form little changed from before. The hind end extends upward into a segmented stalk, growing leaf-thorns. Much of the body stays under the ground, growing root-thorns, which store nutrients. The head sticks just slightly above the ground, catching rainwater to form temporary pools of water.