How to Distinguish from Similar Species: No similar species.
Geographical Range: This species ranges along the north Pacific rim from Japan to southern California.
Depth Range: This species is benthic in coastal waters, subtidal (16-370 m) but on rare occasions at night found swimming at the shore in the intertidal zone.
Habitat: This species is fairly common on bottoms of sand or muddy sand.
History: These small
sepiolids crawl on their arms or swim, and dig shalow depressions in
sea floor in which they rest with their arms rolled under their
They inhabit shrimp beds. Over 80% of their diet consists of shrimp,
crabs, mysids, small fishes, and cephalopods are also eaten.
occurs in the summer and fall in deep water. Each egg (4-5 mm
diameter) is contained in a large (8 mm by 15 mm) capsule.
are attached singly or in small groups to seaweeds or other objects on
Hochberg, F.G., 1998. Class
Cephalopoda: Taxonomic Atlas
of the Benthic Fauna of the Santa Maria Basin and the Western Santa
Channel. Volume 8 part 1: The Aplacophora, Polyplacophora,
Bivalvia and Cephalopoda, pp. 1-250. P.V. Scott and J.A.
Santa Barbara Museum of Natural History, Santa Barbara, CA, USA
General Notes and Observations: Locations, abundances, unusual behaviors, etc.:
Nine species of dicyemid mesozoans have been recorded from the kidneys and branchial hearts of R. pacifica. Of these, only two are known to occur off the west coast: Dicyemennea brevicephaloides and D. parva.
This individual, with body length about 7 cm long not
was also collected by otter trawl in the San Juan
Photo August 2011 by Dave Cowles
Authors and Editors of Page:
Anna Dyer (2002): Created original page
Edited by Hans Helmstetler 12-2002, Dave Cowles 2005