Katharina tunicata 

Black Chiton 

Synonyms: None
Phylum Mollusca
 Class Polyplacphora
  Order Neoloricata
   Suborder Chitonina
    Family Mopaliidae
Katharina tunicata; taken at low tide at Swirl Rocks
Photo by: Ryan Lunsford 2002
Description:  The body of Katharina tunicata can grow up to 12 cm long.  The body is an elongated oval.  The girdle is black, thick, shinny, and leathery; it covers all but the middorsal area.  The valves are embedded in the girdle.

How to Distinguish from Similar Species:  The black chiton is easily distinguished from other chitons by the texture and color of the girdle.

Geographical Range:  Alaska to Santa Barbara, Ca and in Kamchatka

Depth Range:  Very common in the middle and low inertidal zones

Habitat:  They attach to rocks where they are exposed to heavy wave action.

Biology/Natural History:  There is a large amount of molecular and genetic research done on Katharina.  The K. tunicata is diploid and has a haploid number of 24.  The changes in organic composition of the tissues and systems along with the life cycle of the chiton have also been studied.  Lipids and blood proteins levels are high through the majority of the life cycle, but both decrease dramatically prior to spawning.  The organic compositions of most other systems remain fairly constant seasonally.  Damaged plates can be repaired in just a few weeks.  The diet of the black chiton includes brown and red algae as well as benthic diatoms.  Reproduction is sexual and full maturity just over a year.  The entire life span averages 3 years.

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Dichotomous Keys:

Kozloff, 1987.  Marine Invertebrates of the Pacific Northwest.  University of Washington Press.

General References:
Morris, Abbott, and Haderlie, 1980.  Intertidal Invertebrates of California.  Stanford Univ. Press.

Scientific Articles:

General Notes and Observations:
This species is so prevalent in the mid-intertidal region that it can be used as a marker for the intertidal zones.

Authors and Editors of Page:
Ryan Lunsford  (2002):  Created original page
Edited by Hans Helmstetler 1-2003