I'm curious because I thought for a while now that I had some sort of tiny crab living in my sand, because I sometimes see a tiny water bubble in the sand by the glass and two sand-colored or semi-transparent crablike claws a mm or three long pick something (probably algae) from the grains of sand and pull it back towards a body and presumably mouth I can't see. Sometimes it picks up the whole grain. Almost all I ever see is the claws engaged in the sort of activity my emerald crab might engage in on the rocks.
This activity usually occurs a few mm to maybe 2 cm down in the sandbed. After reading the amphipod article, I'm wondering if it might be an amphipod species with a chelate gnathopod instead. (Most of the ones I see are of the standard 'gammarus' look hanging around my rubble pile, but I have at least one species of what looks like an isopod in there, too.) The 'claws' were the same general shape as the chelates in your article, but I only ever see one or two of them and maybe another leg bracing against something.
This activity usually occurs a few mm to maybe 2 cm down in the sandbed. After reading the amphipod article, I'm wondering if it might be an amphipod species with a chelate gnathopod instead. (Most of the ones I see are of the standard 'gammarus' look hanging around my rubble pile, but I have at least one species of what looks like an isopod in there, too.) The 'claws' were the same general shape as the chelates in your article, but I only ever see one or two of them and maybe another leg bracing against something.
