These creeps have been burrowing through mud flats since the supercontinent Pangea began breaking apart, and the first flowers bloomed. I can find living ones and fossilized ones within 20 miles of each other.
Mud, or sand shrimps are widely regarded as a supurb fishing bait for salmon, steelhead, and sturgeon. A nightmare to keep on a hook, use an egg loop, Miracle Thread or a similar elastic thread.
My reference specimens were dug near Seaside, Oregon, taken home and photographed.
9” X 14” Acrylic on Panel
Detail
Above: A Freshly dug, live shrimp, I pumped fresh from a mudflat.
Opposite: Claw parts; carpus, propodus, fixed finger and dactylus of a fossilized shrimp I found along the Columbia River.
Shrimp anatomy and natural history reference - https://depositsmag.com/2017/07/04/the-abundant-yet-understudied-fossil-record-of-ghost-shrimps/