Description:
This solitary tunicate
has a translucent or mostly opaque, light brown tunic. The
tunic
is mostly smooth or slightly wrinkled, without spinelike
projections.
The oral and atrial apertures, both of which are short, are located on
a flattened disk. Each aperture is surrounded by 6 plates,
and other
plates occur on the disk as well. The plates usually have
concentric
growth lines. The muscle strands connecting the two central
disk
plates are not visible through the tunic. There are no
intermediary
plates between the central and marginal plates of the disk.
Height
to 6 cm; disk diameter to 2.5 cm. The tunic is whitish, gray,
or
brownish and appears slightly translucent. It is smooth in
small
individuals but becomes opaque and more wrinkled in older
specimens.
Individuals are often covered with fouling diatoms. The
siphons close
by flaps (photo).
The oral siphon has 75-125
tentacles.
How to Distinguish from Similar Species:Chelyosoma columbianum has disk plates without concentric growth lines, the muscle strands connecting the two central disk plates are visible (at least in preserved specimens), there are one to 3 intermediary plates between the plates surrounding the apertures and the margin of the disk, and the disk diameter rarely is greater than 1.5 cm. Geographical Range: Prince William Sound, Alaska to San Diego, CA. Those in the southern end of the range are usually smaller. Depth Range: Low intertidal and subtidal to 50 (75) m depth Habitat: Rocks; common on floats and pilings. Often several individuals are clumped together. Mostly in quiet waters. Biology/Natural History:
This species is known to feed on barnacle and copepod nauplii
(larvae),
eggs, and the larvae of gastropods and other ascidians. It
reproduces
in spring, releasing its gametes in the early morning (it does not
brood
its young). Fertilized eggs, which may be tan, yellow, or
purple,
hatch into tadpole larvae in 29-40 hours at 11C. After
swimming for
a few hours to a few days, the larvae settle, preferring to settle on
the
tunics of individuals of the same species.
This species may contain up to 800 ppm of the metal vanadium
in the
tunic by weight.
References:Dichotomous Keys:Flora and Fairbanks, 1966 Kozloff, 1987, 1996 Smith and Carlton, 1975 General References:
Scientific Articles:
General Notes and
Observations: Locations,
abundances, unusual behaviors:
Authors and Editors of Page: Dave Cowles (2008): Created original page CSS coding for page developed by Jonathan Cowles (2007) |