New records of ascidians from the NE Pacific: a new species of Trididemnum, range extension and redescription of Aplidiopsis pannosum (Ritter, 1899) including its larva, and several non-indigenous species
Author
Lambert, Gretchen
University of Washington Friday Harbor Laboratories, Friday Harbor, WA 98250 (USA) Address for correspondence: 12001 Ave., NW, Seattle, WA 98177 glambert @ fullerton. edu.
glambert@fullerton.edu
text
Zoosystema
2003
25
4
665
679
journal article
10.5281/zenodo.4525061
1638-9387
4525061
Ciona savignyi
Herdman, 1882
Ciona savignyi
Herdman, 1882: 236
, 237 (
type
locality:
Japan
). —
Hoshino & Nishikawa 1985: 69-71
, figs 1D-G, 3. —
Nishikawa 1991: 33
. — Cohen
et al.
1998: 31, 33. —
Lambert & Lambert 1998: 675-688
. —
Mills
et al.
2000: 135
.
MATERIAL EXAMINED
. —
USA
.
S of Seattle, WA, Des Moines Marina, on ropes on covered floating docks,
1 m
, C. Lambert coll.,
1-8.IX.1998
,
3 specimens
(
CASIZ
162514),
2 specimens
(
USNM
1006927),
3 specimens
(
MNHN
P1
CIO
77).
Puget Sound, WA, Brownsville Yacht Club float,
10.IX.1998
, 3 large specimens in sabellid/mussel clumps.
N of Seattle, Edmonds Marina, on covered floating docks,
IX.1999
, numerous individuals of all sizes.
Tacoma, WA, Yacht Club adjacent to Pt Defiance ferry dock, only on covered floats,
23.IX.2001
, many. DISTRIBUTION. —
Ciona savignyi
is apparently native to
Japan
(
Nishikawa 1991
). It was first recorded from the Pacific coast of North America (as
C. intestinalis
(Linnaeus, 1767))
by
Ritter (1913)
from a collection made in
1903 in
Loring,
Alaska
(
USNM
5633). A second specimen (American Museum of Natural History 1427) was collected from British Columbia in 1937 (also identified as
C. intestinalis
).
Hoshino & Nishikawa (1985)
reexamined these two museum specimens and determined that they were actually
C. savignyi
.
Lambert & Lambert (1998)
first noted
C. savignyi
on the
US
west coast in
1985 in
Long Beach Harbor,
CA
. Their first Pacific NW sightings were at Des Moines Marina south of Seattle in 1998, where the species was very abundant (A. Cohen
et al.
1998;
Mills
et al.
2000
). Though absent in 1998 at Edmonds Marina north of Seattle, it appeared there in large numbers in 1999. It remains abundant at these two marinas and now extends south to Tacoma (unpublished observations).
DESCRIPTION
See
Hoshino & Nishikawa (1985)
for a detailed comparison of
C. savignyi
with
C. intestinalis
. Individuals are long and slender (up to
15 cm
), with usually five (but may be four to six) strong longitudinal muscle bands on each side showing through the translucent yellowish/green tunic. White pigment flecks are scattered in the body wall. As indicated by
Hoshino & Nishikawa (1985)
for this species, there is no endostylar appendage at the base of the endostyle and no red pigment spot at the end of the sperm duct, though both are present in
US
west coast
Ciona intestinalis
. Also agreeing with the description by
Hoshino & Nishikawa (1985)
, there is a pair of large pharyngeo-epicardiac openings very close to the opening of the esophagus, one on each side of the mid-ventral line. The siphons, both anterior, are long and divergent. The oocyte follicle cells of
C. savignyi
contain multiple small refringent droplets as compared with the single droplet per follicle cell in
C. intestinalis
(
Byrd & Lambert 2000
)
.
REMARKS
This species favors shaded locations such as covered floats. Even if it is abundant on these surfaces it is nearly always absent from adjacent uncovered floats.