[2][3] This crab is found on the western side of the Atlantic Ocean, including Brazil, the Gulf of Mexico, Florida, North Carolina and Massachusetts.

[2] Although Chaetopterus variopedatus is of cosmopolitan distribution, P. chaetopterana and another pea crab, Polyonyx gibbesi, are only found associated with it along the eastern seaboard of America from Massachusetts to Uruguay.

The latter is occasionally free living and also sometimes associates with other hosts such as another polycheate worm, Amphitrite ornata.

[4] It is likely that the crabs gain protection from predators within the tubes and gather food in the form of plankton from the water pumped past them by the host worm.

[6] The ribbon worm, Carcinemertes pinnotheridophila, is a parasite found in the branchial chambers of this pea crab, and the worm's eggs can sometimes be seen attached to the hairs on the second abdominal appendage of the female crab alongside her own eggs.