Grazing Crablet
During the collapse of its food supply and much of the Megalomagnus Watershed's surrounding biosphere the surviving, isolated groups of Multis parva were forced into various new niches. One group, without the polyphs that made up its diet, turned to the widely abundant carpets of Sustonomum legumenfluvius. While less nutritious and more difficult to digest the large size of the polyphs, combined with their tendency to grow as flat sheets along the seafloor, allowed the Crablets to spend much longer periods eating, staying stationary and camouflaged from predators. To help facilitate this their shell has taken on a tan coloration while the dark brown stripe has become more speckled and diffuse.
While maintaining the same general body plan as their ancestor M. tapetophagus are considerably smaller, with large specimens measuring just 10cm from tip to tail. Additionally the claws are much weaker, suitable only for collecting vegetation and bringing it to the mouth, while the shell has substantially thickened and the stripe on the back has become more uneven and spotty to better blend in with the substrate. M. tapetophagus lives a grazing lifestyle in which a group, generally of 5-30 individuals eat from the same polyph for a period of hours to days before moving on. Their thickened shell makes swimming difficult so they vastly walk on the riverbed, this being the period in which they are most vulnerable and are eaten by their primary predator, Naukis adriticaris. They have an enlarged clutch of eggs, 45-70 per female per season, and tend to lay eggs near the center of S. legumenfluvius patches where food and shelter are almost always available. Counterintuitively, groups of M. tapetophagus preferentially seek out older, tougher S. legumenfluvius, especially when the group includes gravid females. This is to avoid having food taken by the much more mobile Motoslontus pascebantur and because these older polyphs tend to be larger, the greater quantity of food and shelter making up for the reduced quality.