Soilswimmer

River crab the crust of a tan crab imbibed by the sand. Soaking up the first of the land.

The Lowlands around the Coastal Mountains are swampy marshes bordering the Global Ocean. These brackish waters act as a throwback to the Silurian here the Arthropods rule the roost as Silver Swimmers evolve into forms remarkably similar to their ancient relatives. 

However well many become more efficient aquatic hunters one species is taking a different route as the Silt Swimmers are landward bound.

 Well, many other Riverine Silverswimmers are becoming more like the Eurypterina suborder the bottom feeding Silt Swimmer is becoming more like the Stylonurina having completely lost their swimming fins millions of years ago and well their ancestors dragged themselves along the floor of bodies of water the Soilswimmers like some of the last Stylonurians can drag themselves along the shoreline. 

Like modern land crabs as long as the Soilswimmer's gills remain moist they can survive out of water indefinably. Soilswimmers use this to their advantage being able to feed and spawn in places that their relatives can't let the Soilswimmers proliferate into areas outside of the Lowlands riverways. 

Of course, Soilswimmers aren't at all truly terrestrial there about as agile on land as a Horseshoe Crab holding themselves on their telson and dragging themselves with their 10 legs and underside swimmerets.

 As slow-moving animals, they fall prey to many animals on both land in the form of Blish, Hoppers, and Terra Squids and water in larger Silverswimmers, Lungefish, and Finger-Fish.

 Soilswimmers' main defense against aquatic predators is to flee onto land although this puts them in the line of land predators. Against land predators, their only defense is to flash their bright-colored limbs and telson hoping that it will deter predators from eating them by thinking they're toxic this usually goes down with mixed results this usually works with hoppers but more intelligent Blish won't fall for it on the second try.