Rhombozoans: Rhombozoa

Physical characteristics: The body length of an adult Dicyemodeca deca (abbreviated as D. deca) does not exceed one–thirty-second of an inch (1 millimeter). There are twenty-three or twenty-four outer cells. The cap is disk shaped. The specialized embryos consist of thirty-five cells and are approximately 0.001 inch (33 micrometers) long.

Geographic range: D. deca lives in the northeastern part of the Pacific Ocean.

Habitat: D. deca lives in the kidneys of the giant Pacific octopus.

Diet: D. deca absorbs nutrients from the urine of its host.

Dicyemodeca deca lives in the kidneys of the giant Pacific octopus. (Illustration by Marguette Dongvillo. Reproduced by permission.)

Behavior and reproduction: The wormlike and specialized embryo forms of D. deca swim by movement of their hairlike fibers. Adults have two sex organs that contain about sixteen egg-related cells and fifteen sperm-related cells.

Dicyemodeca deca and people: D. deca has no known importance to people.

Conservation status: D. deca is not threatened or endangered. ∎