Chitons - Leptochitonidae,Chaetopleuridae,Ischnochitonidae

Hanleyella oldroydi (Dall, 1919)
subtidal to 455m
northern Mexico to southern Alaska
This is a very small species of less than 1cm in length. It seems to be more commonly found in the southern end of its range.

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

Cape Arago, OR, intertidal

Lepidozona cooperi (Carpenter, 1879)
Cooper's Chiton
intertidal to 20m northern Mexico to northern BC size to 5cm
It 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 Lepidozona
very 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)

Bremerton, WA, intertidal Bremerton, WA, intertidal Bremerton, WA, intertidal Oak Bay, WA
uncommon turquoise and albino color

Lepidozona radians (Carpenter, 1892)
intertidal to at least 13m northern Mexico to southeastern Alaska size to 2.5cm
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.
(synonym - Ischnochiton radians)

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. Sometimes the plates can be solid red or white. This species has very distinctive sculpture on the plates.

San Juan Islands, WA, subtidal
Lepidozona retiporosa (Carpenter, 1864)
Little Lepidozona
subtidal to 1000m size to 2cm
northern Mexico to southern Alaska
It is often found near Lepidozona willetti.

preserved specimen, Ketchikan, AK
Lepidozona willetti (Berry, 1917)
Willett's Lepidozona
subtidal size to 3cm
southern California to southern Alaska
It is very similar to Lepidozona retiporosa and often found near that species. This species is usually orangish to reddish-brown.
(synonym - Ischnochiton willetti)

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)

Petersburg, AK, intertidal Anacortes, WA, intertidal Anacortes, WA, intertidal

Leptochiton cf. rugatus (Carpenter, 1892)
Dwarf Chiton
intertidal northern Mexico to northern Alaska size to 16mm
They are not uncommon, but can be difficult to find due to their small size. They are generally white or buff colored. At lower tidal levels search under rocks resting on anoxic mud. This is a species complex in the northern Pacific and is currently
under investigation (D.J. Eernisse, pers.comm.).

Chitons (Polyplacophora)

Family Leptochitonidae, Chaetopleurida

& Ischnochitonidae