Mopalia spp. (Mossy, hairy, and woody chitons)
2005 Mary Jo Adams
species from the genus Mopalia can be found on beaches in the Puget
Sound area. They are distinctive in having hairs or bristles
sprouting from their girdles. Chitons from this genus are
also unusual because while most chitons are strictly herbivores,
the Mopalias consume animal materials including sponges,
bryozoans, and hydroids in addition to algae.
muscosa , the mossy chiton (pictured above), reaches a length
of about 3-½ inches and the red-brown hairs sprouting from
its girdle have a bristly texture. The valves (overlapping
plates) are dull shades of brown, black-olive, or gray and may be
overgrown by encrusting organisms or seaweed. This species
is often found out in the open on rocks.
ciliata , the hairy chiton, is about the same size as M.
muscosa but is more likely to be down in crevices or underneath
rocks. The brown hairs on its relatively wide girdle are soft to
the touch and it has a distinct notch at the posterior end.
Both the valves and the girdle can vary in color. The valves
may have shades of green, white, red, brown, or yellow with streaks
or blotches of white or other colors. Girdle color can be
dark green, pinkish, or white. This species is an omnivore.
Mopalia lignosa ,
the woody chiton, can also be colorful. Valve colors include
gray-brown, bluish, or green with feathery markings. Additionally,
rows of pits may be seen on the valves. The narrow girdle may
be cream, brown, or purple brown with light spots from which sprout
soft hairs. The woody chiton grows to a length of about 3 inches
and is found on the sides or undersides of boulders. It feeds
primarily on Ulva (sea lettuce).
This page was created by Mary Jo Adams on 12/6/05.