This compound tunicate (many
individuals are embedded in a common tunic) grows in a globular
flat) mass with a short, narrow attachment stalk. The
not encrusted with sand. The pharynx of individuals has 4
Colored from pale orange to yellow to pink to dark purplish-red or
Most colonies are less than 2 cm in diameter, though they can be larger
as here (up to 10 cm). Each of the closely packed zooids has
own incurrent siphon and pharynx, but several adjacent zooids share a
raised common buccal or excurrent siphon and atrial cavity.
Distaplia occidentalis Bancroft, 1899
Common name(s): Mushroom ascidian
|Distaplia occidentalis from about 20
m depth, Sares Head, WA.
The attachment stalk is at the bottom.
|(Photo by: Dave Cowles,
How to Distinguish from
Several species of similar shape are often sand-encrusted and have 5 or
more rows of stigmata. Distaplia
smithi, which lives on the open coast, is a cluster of
lobes. Of the other common, smooth orange local
taylori is a social ascidian in which
individuals live near
each other and are often connected with narrow stolons or sheets of
but are not enclosed within the same lump of tunic. Cnemidocarpa
finmarkiensis is a solitary tunicate with a very
Canada to San Diego, CA
Intertidal to 15 m
Protected floats and pilings,
subtidal on rocks with good current, among surfgrass roots, open coast.
to late August. Each zooid produces 2-4 sausage-shaped eggs,
are retained in a brood pouch of the atrial cavity until the tadpole
stage. Larve are released mainly in the morning.
and Fairbanks, 1966
and Carlton, 1975
and Snook, 1955
et al., 1980
Watanabe, H. and C.C. Lambert,
release in response to light by the compound ascidians Distaplia
occidentalis and Metandrocarpa
taylori. Biological Bulletin 144:
General Notes and
Observations: Locations, abundances,
Each individual has its own separate incurrent (oral) siphon but the
excurrent (buccal) siphon is shared by several adjacent
This closeup shows the arrangement of individuals.
Authors and Editors of Page:
Dave Cowles (2006): Created original page