Filter Feeder

This pencil image is visual development for my book project, and is a creature evolved from this body plan. [link]

One of the largest quadrilaterians on Chriirah, the lyre sardu has become a highly specialized plankton feeder. Water is drawn into the mouth in the manner of terrestrial whale sharks and squeezed into pouches in either side of the flattened head. Once the mouth is closed, the water is forced out through a long curved slot mirrored on the upper and lower surface of the head, passing through a fine filter to retrain prey.  An airbreather, the lyre sardu nears the surface and extends a fleshy breathing tube from a small orifice on the right-hand side of the head.