Saltjorn

Saltjorns live in the splash zone of beaches, where (other than rain) the only water comes from sea spray or the highest storm waves. Their shells are made with chitin, with small deposits of excess minerals absorbed from the surrounding soil or water. The minerals make the shells slightly harder than their ancestor's, but their function is primarily to sequester substances that would be harmful in large quantities. One of these substances is sodium. Certain populations accumulate so much sodium that they effectively become salt licks for any organism able to pulverize the shells. (though there's not much demand for their use as salt licks, since they are so close to the sea) Photosynthetic cells protrude in spike shapes from the holes in the shells. The spiky shape allows them to better photosynthesize, as some light will be falling on their surfaces no matter which direction the sunlight is coming from. The photosynthetic cells sit in a thin, brittle mesh made from silicon compounds. The mesh easily breaks if a small organism sits upon them or applies enough force to a small area (such as by a punch). Fortunately for the saltjorn, it easily regrows its photosynthetic spikes. The broken-off pieces can even regenerate into another saltjorn if exposed to enough water. Saltjorns and Fermi chitjorns coexist by splitting up the beach habitats by proximity to the sea. Saltjorns dominate parts of the beach closer to the sea, and Fermi chitjorns dominate parts of the beach that are farther away.