Gillstar
Split off from the predestar, the gillstar took a weird direction with its evolution, especially the use of its arms. Three of its arms have shortened with the fingers elongating, using modified cellularized versions of its existing baits to create three branching gills; this allows it to get the oxygen necessary to power its larger body. The last arm, the anal arm, has its fingers modified into 3 tentacles. The purpose of these is to help it dig into sediment and hold onto buried rocks and roots so that it may just hang out and let microscopic food and oxygen make its way over its gills. It has blood, and it uses hemoglobin.
Its mouth now remains mostly in the “inverted” state, and instead of sucking it inwards to catch larger meals it shoots it outwards to grab them. This is less efficient, but it protects its mouth from damage when it isn’t feeding, so it grants an advantage. Like its ancestor, it mostly feeds on other asterzoa.
The gillstar has a pair of simple eyes consisting of smooth raised skin covered in dark pigment, almost like an inverted pigment cup, which it uses to identify prey, or a threat, based on the size and movement of what it perceives as dark blurry blobs. In the face of a predator, it cannot yet go underground to protect itself; however, it can swim using its strong anal arm, so it does so as needed. Like its ancestor, it mates to reproduce; with its added complexity, it cannot reproduce by fragmentation anymore, mostly because it is dependent on its gills to survive. Its offspring begin as radially symmetric and free-swimming with all four arms having both the tentacle-like fingers and the gill features, their arms differentiating later as they mature.