Landels-Hill Big Creek Reserve, Big Sur Coastline
Monterey Co., CA – March 9, 2002

The lined chiton, Tonicella lokii Clark, 1999. Most central California
Tonicella spp. were formerly referred to as T. lineata, which is a more
northern species as recently concluded by Clark (1999). Also present
in central California are T. lineata (rare in Monterey Co.), T. undocaerulea
Sirenko, 1973, and T. venusta (not known from less than 10 m depth in
central or southern California). The easiest way to tell T. lokii and
T. undocaerulea from T. lineata is by the pattern of lines on the head
valve, which is unfortunately not well illustrated above. T. lineata
lacks "zigzag" concentric lines found in the other two (see the specimen
correctly identified at this website, under T. lineata). Its concentric lines
characteristically form a "gothic arch" without zigzags.
T. lokii differs
from T. undocaerulea in having dark maroon-brown to nearly black lines
on its valves, which will generally also transition to white or bright blue.
T. undocaerulea, which is also found discontinuously in the western Pacific,
e.g., Japan, has whitish lines without the dark maroon-brown to black
lining. Here are two more chitons observed 3/24/02 approximately 2 miles
north of Piedras Blancas near San Simeon (the top two are the same chiton).

Clark, Roger N. 1999. The Tonicella lineata (Wood, 1815) species complex
    (Polyplacophora : Tonicellidae), with descriptions of two new species.
      American Malacological Bulletin

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Image by D.J. Eernisse © 2002