Tonicella lineata (Wood, 1815)

Common name(s): Lined chiton

Synonyms:  See note below on Tonicella undocaerulea
Phylum Mollusca
 Class Polyplacophora
  Order Neoloricata
    Suborder Chitonina
     Family Lepidochitonidae
Tonicella lineata, San Simeon, CA.  About 2 cm long
(Photo by: Dave Cowles, 1995)
Description:  This small chiton is distinctive because it has zigzag pink and blue, red, or white lines on the 8 smooth plates (picture).  Up to 5 cm long.  The girdle is smooth and leathery, often with a row of lighter spots or bands.

How to Distinguish from Similar Species: No other local chiton species has this coloration on the plates.

Geographical Range: Aleutian Islands to San Miguel Island, CA, Sea of Okhotsk, northern Japan

Depth Range: Low intertidal and subtidal.

Habitat: Rocks covered with coralline algae.

Biology/Natural History:_Feeds on coralline algae.  Often is found living under the purple urchin Strongylocentrotus purpuratus or in urchin burrows in the rock.  This species may home.  Predators include Pisaster ochraceous and Leptasterias hexactis, at least in some regions.  Eggs are released in April in CA and OR, but in June in the San Juan Islands.  Lays a stream of green eggs.  Trochophore larva development stops after 150-160 hours, and will not resume unless the larva settles on coralline algae.  Larvae metamorphose into juvenile chitons within 12 hours of settling.

Some workers identify the form with pink, blue, and red lines on the plates as T. undocaerulea and identify T. lineata as the form with pinkish valves and dark zigzag lines edged with white.

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

General References:
Morris et al., 1980
Kozloff, 1993
Niesen, 1994
O'Clair and O'Clair, 1998

Scientific Articles:

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

This Tonicella lineata was under a rock, seen in early morning light.
Note the variation in plate color compared to above picture.
This would conform to the classic Tonicella lineata (see note above)
Photographed at San Simeon, CA by Dave Cowles.  About 3-4 cm long.

Another individual.  Dave Cowles, San Simeon, CA 4-97

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