​Neotrypaea californiensis, also known as the Bay Ghost Shrimp, is found in flats of bays and estuaries of the eastern Pacific, ranging from Alaska all the way down to Baja California, Mexico.  Ghost shrimp are often found coexisting with scale worms, snapping shrimps, pea crabs, and burrowing clams, other organisms that live in the muddy estuarine environment.

 

They have adapted to a permanent life in the burrows they dig in muddy or gravelly sand, which can be up to 75 centimeters deep and sprawl out in many directions.  The environment underneath a meter of sediment can be a nearly anoxic condition, so their blood has evolved to include a hemocyanin respiratory pigment which helps facilitate oxygen uptake and distribution to tissues all over the body.  The first fossils of Ghost Shrimp arise from the Jurassic period of the Mesozoic era.