This large, brightly
colored seastar ideally has 5 long arms (rays),
though since it often suffers loss of one or more rays
and grows them back only slowly it often is seen with less than 5 rays.
Although there are several different kinds of spines and plates along
are not greatly enlarged. The aboral
row of plates on each ray
contains very long spines, often 4-5 mm long, with each spine
with a fleshy cushion of small crossed pedicellariae (photo).
This row of spines is fairly well-defined along the aboral
surface and is called the carinal spines (photo).
There are several ragged rows of similar spines along each ray
lateral to the carinal row (photo).
Bordering the ambulacrum
on the oral
mouth plates which are usually so sunken that they cannot be seen, then
a row of prominent adambulacral plates, each of which contains two
then a row of small
"oral intermediate" spines. Most large spines and many areas
the spines contain abundant pedicellariae,
many of them prominent, and of many different sizes and shapes (photo).
pouches used for respiration and excretion, are also large and
especially near the oral side next to the adambulacral plates (photo).
can be up to 25
cm long each, and the central disk diameter is only about the same as
diameter of the rays,
about 1/6 to 1/10 the ray
length. The color is blotchy, generally with various colors
red with white or tan or cream but some individuals may be straw
or blue. The large spines are usually white but may be
koehleri (de Loriol,
Common name(s): Rainbow star, long-armed sea star, longrayed
red banded sea star, painted star, fragile star
koehleri, Orthasterias columbiana
70 m depth, San Juan Channel. This individual recently lost
its rays. Ray length is 20 cm.
|(Photo by: Dave
How to Distinguish
Similar Species: Stylasterias
forreri is similar in shape and spines but is brown,
olive, or gray
without red and has differences in its spines and pedicellariae. Evasterias
troschelii has a generally similar body shape
and variable coloration
but its rays
a short distance from the central disk and it does not have the
series of large spines surrounded by fleshy cushions of pedicellariae.
Islands to northern Mexico.
Intertidal or (usually)
subtidal to 283 m or more
Rock, pebbles, sand, and
have indicated that this species may eat a variety of prey such as
limpets, bivalves, chitons, squid, brachiopods, barnacles, crabs, fish,
and tunicates but it seems to especially eat bivalves. It can
its large tube feet to pull clams up out of the sediment, then chips
some of the margin of the shell until it can insert its stomach and
the clam. Breeding occurs from June to August.
elevate themselves from the bottom on their arm tips.
at least 9 years. The polychaete worm Arctonoe
fragilis is commensal on this seastar (photo).
and Fairbanks, 1966
and Carlton, 1975
and Pill, 1972
and Laurent, 1979
and Snook, 1955 (As Orthasterias columbiana)
and Hanby, 2005
et al., 1980
Knott, K. Emily, and Gregory A. Wray, 2000. Controversy and consensus
in Asteroid systematics: new insights to Ordinal and Familial
relationships. American Zoologist 40:3 pp. 382-392
Mauzey, K.P., C. Birkeland,
1968. Feeding behavior of asteroids and escape responses of
prey in the Puget Sound region. Ecology 49: 603-619
General Notes and
abundances, unusual behaviors:
Older references such as Johnson and Snook (1955) state
is common intertidally. However, my experience and several
references confirm that now this species is much less common
(in other words, view from the top) of the ray
shows the line of large carinal spines down the aboral
surface and the ragged rows of spines on each side. Notice
of small pedicellariae
which surround each spine. Also notice the large individual
and the abundant papulae
between the spines. Photo by Dave Cowles, July 2008
This lateral view of the rays
shows the scattered rows of spines, the abundant large pedicellariae
spines, and the rows of adambulacral spines along the bottom.
|Views of the oral (ambulacral) region of the rays.
Photos by Dave Cowles, July 2008
|This lateral view of the ambulacral
area of the rays
scattered rows of ray
surrounded by cushions of small pedicellariae
along the sides of the ray.
Below that is a section of prominent papulae
which are largely obscuring the row of small oral intermediate
At the bottom of the ray
can be seen the forked adambulacral spines which also have pedicellariae
around them, and the tube feet are at the very bottom.
||This oral (ambulacral) view of a ray
shows the 4 rows of long tube feet. The forked adambulacral
are visible along the margins of the ambulacral groove, though the
around the spines is so dense that the two forks look like two separate
rows. The mouth plates, which are between the ambulacral
groove and the adambulacral spines are apparently sunken and
This closeup view shows the abundant pedicellariae
large spines. The small crossed pedicellariae
in the cushions around the spines are mostly retracted in this view but
a number of the individual pedicellariae
between the spines are open.
The polychaete worm Arctonoe
fragilis is often found as a commensal on this
cannot distinguish the dorsal plates (elytra)
on this worm but perhaps they have broken off and simply left the white
bases. The worm seems to spend the large majority of the time
even though that
is where all the large pedicellariae
are. I wonder what kind of relationship it and the seastar
prevents the worm from being severely pinched?
Authors and Editors of Page:
Dave Cowles (2008): Created original page
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