Clausidium dissimile is a species of copepod that has been found along the Atlantic and Gulf Coasts from Massachusetts to Florida.

(probably C. stimpsoni [4]); Cold Spring Harbor, Long Island, New York [1] Gilvossius setimanus (Syn.

Callianassa stimpsoni, Callianassa atlantica); Vineyard Sound, Massachusetts [4] Unknown; Wassaw Sound, Cabbage Island, Chatham County, Georgia [7] Callichirus major; North Beach, St. Catherines Island, Georgia [8] Callichirus major (Syn.

Callianassa islagrande); Alligator Point, Franklin County, Florida [5] Lepidophthalmus louisianensis (Syn.

Callianassa jamaicense); Big Sabine Point, Santa Rosa Sound, Pensacola Beach, Florida [3] Biffarius biformis (Syn.

Callianassa biformis); Big Sabine Point, Santa Rosa Sound, Pensacola Beach, Florida [3] Sergio trilobata (Syn.

Callianassa trilobata); Big Sabine Point, Santa Rosa Sound, Pensacola Beach, Florida [3] The relationship between C. dissimile and its host has not been definitively characterized, but is not likely to be parasitism.

An examination of the gut contents of C. dissimile showed diatom frustules along with unidentified material.

C. dissimile were also observed beating their antennae causing a current which moved suspended particles to the mouth.

[3] Clausidium dissimile has been found in estuarine habitats and areas exposed to the open ocean.

This ability may allow it to survive periods when water circulation is reduced or eliminated by low tides or sand clogging the burrow entrance.

[3] At Big Sabine Point, Pensacola Beach, Florida, C. dissimile begins settling on the host at the copepodid II and III stages in March and April.

[3] At a location in Tampa Bay, Florida, the maximum infestation rates observed was approximately 90 to 100 copepods per host.

[3][10] In Tampa Bay, Florida, C. dissimile colonizes ‘’Sergio trilobata’’ at a higher frequency than ‘’Lepidophthalmus louisianensis’’.