Linzor
The linzor derives from stinzerstars that specialized in littoral zones, living throughout the tropical beaches surrounding the Flisch and Rhino Seas. As these beaches were unexploited, they were able to take over a wide-open niche and greatly expand in size. The adults are equally comfortable in air and in the water, and they spend most of their time wandering the tidal zones. They must enter the water periodically to keep their gills moist, usually during the peak heat of the day, but they will rest on the land, where the predators are further inland than they venture. This also makes them the first fauna in Hydro and the first terrestrial asterzoan in Barlowe.
Reproduction remains bound to the water. They no longer bother with tidal pools, instead giving birth directly in the ocean. They are more r-strategists than their ancestor, giving birth to many young with much less parental care. The larvae inhabit the Flisch and Rhino Seas, with the ancestral radial symmetry, until they develop their adult shape and go to a littoral area.
Linzors entirely specialize in eating food with chitinous shells, whether flora or fauna, and they've honed their dentition for this lifestyle. The front of their "tongue" and palate contains grasping teeth for latching onto their food, while the back contains molariform teeth for crushing it. This lets them chomp through large crystals as well as grinding tiny ones. Their massive crushing teeth result in a wide and heavy jaw, with a robust square-jawed face. The lateral mandibles are also adapted for crushing, thick and heavy, though they have little gripping barbs in front (too small to easily see).
As frequent swimmers in crowded seas, they have new adaptations for swimming. Their dorsal fin is expanded in the form of a membrane supported by extensions of the neural spines of the anal arm. In addition to this, the webbing in the caudal fin, and the webbing between the fingers, they have new membranes that extend behind the lateral and raptorial arms, which engorge when swimming, allowing the lateral arms to serve as paddles. They also use these, especially the dorsal sail, for thermoregulation when on land, shedding excess heat in their tropical habitat.
They are otherwise similar in form to their ancestors. It retains hemerythrin-using magenta blood, four lungs, and an internal skeleton.