Mopalia muscosa (Gould, 1846)

Common name(s): Mossy chiton
Synonyms:
Phylum Mollusca
 Class Polyplacophora
  Order Neoloricata
    Suborder Lepidopleurina
     Family Mopaliidae
Mopalia muscosa under a rock at San Simeon, CA.  Length is about 3 cm.  Head and plate 1 are to the left.
(Photo by: Dave Cowles, 1995)
Description:  This chiton has a wide girdle covered by a thick mass of long, mossy , stiff, rubbery hairs.  The girdle is about the same width all around, and no plate is dramatically larger than the others.  The dorsal surface of the girdle, between the hairs, is not especially granular.  Body to 9 cm long but more often is around 3 cm.  Valves (plates) dull brown, dark olive, or gray; may be eroded or overgrown with algae.  Barnacles may even settle on the plates.

How to Distinguish from Similar Species: The other Mopalia species with hairs on the girdle, such as Mopalia lignosa, have thinner, flexible hairs.

Geographical Range: Queen Charlotte Islands, Canada to Isla Cedros, Baja California

Depth Range: Middle and low intertidal

Habitat: On rocks, especially in areas of low to moderate surf.  Also found in estuaries.

Biology/Natural History: Moves at night at high tides.  This species homes to a special place on the rock after each trip.  Home ranges of different individuals usually do not overlap.  Permanently submerged individuals in tidepools may not home.  Feeds primarily on the red alga Mastocarpus papillata and Endocladia muricata, green alga Cladophora.  Larvae will settle on rocks or shells covered with an algal film.


 
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References:

Dichotomous Keys:
Kozloff 1987, 1996
Smith and Carlton, 1975
Flora and Fairbanks, 1966
 

General References:
Morris et al., 1980
Kozloff, 1993
Niesen, 1994
 

Scientific Articles:
 


General Notes and Observations:  Locations, abundances, unusual behaviors:
 


This individual was on the rocky head on the south side of Bowman Bay.  Photo by Dave Cowles, July 2008


Authors and Editors of Page:
Dave Cowles (2005):  Created original page