The spinderorm split from it's ancestor for more plentiful food. Their most striking adaptations that of their sensory organs. Their hair like sensors have grown into an intertwined membrane, which has the added bonus of functioning as a fin. Their internal structure has adapted as well. Now that they can taste their surroundings much more efficiently, they are able to selectively choose their food. They now go after phytoplankton, tasting when the levels of them spike in the water, meaning they has found a plume. Their internal digestive processes work specifically for this and their digestive processes only begin when they find a plume. Their "mouths" stay shut until they find a plume then it is triggered to open up wide. Their gastric juices contain enzymes that actively break down the cell walls of the microbes they eat. Like their ancestors as far back as the oceanrorm, any water ingested is expelled through their skin.