Chitons (Polyplacophora)
Family Chaetopleuridae & Ischnochitonidae
Chaetopleura gemma Dall, 1879
Gem Chiton
intertidal northern Mexico to southern BC size to 2cm
This is a very small species and rarely found in the Northwest. It has a dark spot on the posterior valve which is distinctive for the species.
(synonym - Ischnochiton marmoratus)
Ischnochitonidae
preserved specimen
photographed intertidally
Lepidozona cooperi (Dall, 1919)Cooper's Chitonintertidal to 20m northern Mexico to northern BC size to 5cmIt is infrequently found intertidally to the north. This is similar to the Merten's Chiton but with strong
shell sculpturing and smaller girdle granules. It is usually
grayish in color. It seems to be primarily an outer coast species and
not found in interior waters. (previous name - Ischnochiton cooperi)
photographed subtidally
Lepidozona interstincta (Gould, 1852)Smooth Lepidozonavery low intertidal
to 70m size to 3cm
Washington to
north Alaska This is a small species which lacks obvious sculpturing on its plates. The color is tan or more commonly, rusty red. It is virtually identical to L. radians, but has a smaller range and deeper habitat. They can also be distinguished via DNA.
(previous name - Ischnochiton interstinctus) uncommon turquoise and albino color - intertidal
good example of its sculpture detail
Lepidozona mertensii (Middendorff, 1847)
Merten's Chiton *
intertidal
to 91m northern Mexico to northern
Alaska; Japan size to 5cm
This is a common intertidal species. The girdle is very granular in appearance and usually banded. It is usually red with creamy white and is variably patterened. The plates can run the extreme from all red to all white.
preserved specimen Lepidozona willetti Berry, 1917Willett's Lepidozonasubtidal size to 3cmsouthern California to southern AlaskaIt is very similar to Lepidozona retiporosa andoften found near that species. This species is usually orangish to reddish-brown.
(previous name - Ischnochiton willetti)
preserved specimen
found subtidally
Lepidozona retiporosa (Carpenter, 1864)Little Lepidozonasubtidal to 1000m size to 2cmnorthern Mexico to southern AlaskaIt is often found near Lepidozona willetti.
This page last revised: 8-18-2020
all photographed intertidally
Lepidozona radians (Carpenter, 1892)
intertidal to at least 13m size to 2.5cm
northern Mexico to southeastern Alaska
This is infrequently found intertidally. It is virtually identical to L. interstincta,
but this species is found at shallower depths and over a wider
geographic range. It is also variably colored and patterned.
(previous name - Ischnochiton radians)
found subtidally
Tripoplax trifida (Carpenter, 1864)
Three-Rib Chiton
intertidal to 110m size to 6cm
Puget Sound, WA to northern Alaska
This
is rare to find intertidally. It is usually reddish and sometimes
patterned. It has three low, flat ribs on the lateral areas of
the central valves.
(previous names - Ischnochiton trifidus, Lepidozona trifida)
Chaetopleuridae
preserved specimen
Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.