Chitons - Mopaliidae

Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.

typical intertidal appearance a freshly dead specimen photographed subtidally photographed intertidally

plates juvenile

Cryptochiton stelleri (Middendorff, 1847)
Giant Pacific Chiton or Gumboot Chiton *
intertidal to 20m size to 35cm
southern California to northern Alaska; Japan
This is a fairly common intertidal species and is the largest chiton species in the world. The girdle completely covers the plates.
The disarticulated plates are often called "butterfly shells".

plates

Katherina tunicata (Wood, 1815)
Black Katy Chiton *
intertidal to 40m size to 15cm
southern California to northern Alaska; Siberia
This is a common intertidal species with a distinct black, leathery appearance. The girdle covers everything but the very center of
the plates. (Photographed intertidally.)

preserved specimen photographed subtidally photographed intertidally

Dendrochiton flectens (Carpenter, 1864)
Painted Dendrochiton
intertidal to 24m southern California to southern Alaska size to 3cm
This species is infrequently found intertidally in the Northwest. It can be red, orange or green with blue, green or gray speckles. There is a single row of long bristles on the posterior end.
(previous names - Leptochitona flectens, Leptochitona heathii)

preserved specimen photographed subtidally

Mopalia egretta Berry, 1919
Egret-Plumed Mopalia
subtidal from 25 to 77m Washington to Alaska size to 2.5cm
This is a somewhat rare species. It can be buff colored to brown
to red. The hairs are very fine and branched.

preserved specimen photographed intertidally

Mopalia hindsii (Sowerby, 1847)
Hind's Mopalia *
intertidal to shallow subtidal size to 10cm
southern California to central Alaska
This is a somewhat common species. It is usually dark
brown to olive-green. It is has a wide brown girdle with a
cleft on the posterior end. The plates are almost smooth
or slightly pitted.

preserved specimen all photographed intertidally

Mopalia imporcata Carpenter, 1864
Branch-Haired Mopalia
intertidal to 120m northern Mexico to southern Alaska size to 2.2cm
This species is infrequently found intertidally in the Northwest. It is usually
pale brown to dark grayish-brown with some red or white markings. It has
thick, scattered hairs along it's girdle and defined sculpturing.

photographed intertidally
Mopalia ferreirai Clark, 1991 *
intertidal to 18m size to 5cm
northern California to southern Alaska
This species can be found intertidally with a little searching.
Look under large rocks. It is extremely variable in color and
pattern with clearly defined sculpturing.

preserved specimen all photographed intertidally rare 7-plate specimen

Mopalia kennerleyi Carpenter, 1864
Northern Hairy Chiton *
intertidal to subtidal northern Mexico to northern Alaska size to 7.6cm
This is a somewhat common species. It is highly variable in color and has numerous short,
flattened hairs on the girdle.

preserved specimen photographed intertidally

Mopalia spectabilis Cowan & Cowan, 1977
Red-Flecked Mopalia
intertidal to 30m northern Mexico to central Alaska size to 7cm
This species is occasionally found intertidally. It has distinctive orange-red zigzag bands
and turquoise blue markings. The girdle is often banded. It prefers an active current or tidal wash.

preserved specimen
Mopalia sinuata Carpenter, 1864
Dwarf Hairy Mopalia
intertidal to 200m size to 2cm
central California to southern Alaska
This very small species is rarely seen.
It can be variable in color but is usually brown.
It is covered with long, yellowish hairs.

plates photographed intertidally

Mopalia muscosa (Gould, 1846)
Mossy Chiton *
intertidal to 5m northern Mexico to southern Alaska size to 10cm
This is a common species. It has thick, bristly hairs on the girdle. The plates
are often eroded and are a distinct blue color on the underside.

preserved specimen all photographed intertidally

Mopalia swanii Carpenter, 1864
Swan's Mopalia *
intertidal to 19m southern California to northern Alaska size to 10cm
This is a fairly common species. It is highly variable in color. The plates are wide and only moderately
sculptured. The girdle is also wide and fleshy and seems almost hairless. Close inspection shows
sparse, fine hairs. It also has a distinct posterior cleft.

preserved specimen photographed subtidally

Placiphorella rufa Berry, 1917
Red Veiled-Chiton
intertidal to 45m size to 5cm
southern Oregon to northern Alaska
This is rarely seen intertidally. It has red plates
and a white girdle making it very distinctive. It
prefers habitats with moderate to heavy currents.

preserved specimen
Placiphorella pacifica Berry, 1919
Pacific Veiled-Chiton
deep subtidal to 2000m size to 4cm
central California to southern Alaska
It is milky white with a pale girdle.
There is debate as to whether this species
is synonymous with Placiphorella atlantica.

all photographed intertidally
Mopalia vespertina (Gould, 1852)
Smooth Mopalia
intertidal to subtidal central California to southern Alaska size to 8cm
This species is occasionally found intertidally in the Northwest. The color is usually shades of
green or brown but may have variable patterns and blotches of white. The sculpturing is mild
and there are sparse hairs on the girdle giving an overall appearance of smoothness.
(previous name - Mopalia laevior)

preserved specimen photographed intertidally

Placiphorella velata Dall, 1879
Veiled-Chiton
intertidal to 20m size to 6cm
northern Mexico to central Alaska
This is infrequently found intertidally. The plates
are usually dark in color but may be streaked
with other colors. The girdle may be reddish-
brown or yellowish.

Mopalia lignosa (Gould, 1846)
Woody Chiton *
intertidal to subtidal size to 8cm
northern Mexico to central Alaska
This is a common species. It is highly variable in color and
usually has the distinctive streaks of lines running the length
of the chiton.

preserved specimen photographed intertidally

Mopalia cirrata Berry, 1919
Long-Haired Mopalia
very low intertidal to subtidal California to Alaska size to 22mm
This species is infrequently found intertidally in the Northwest. It is variable in color with spots
and streaksof color. The longest hairs may be half as long as the entire chiton.

Chitons (Polyplacophora)

Family Mopaliidae