Systematic notes on some leptomedusa species with a description of Neotima galeai n. spec. (Hydrozoa, Cnidaria)
Author
Peter Schuchert
text
Revue suisse de Zoologie
2017
124
2
351
375
journal article
31835
10.5281/zenodo.893549
2f791191-ae08-4795-b02f-6a4ed2e3e15d
893549
Clytia
gregaria
(
L. Agassiz, 1862
)
Fig. 18
A-C
Oceania
gregaria
L. Agassiz, 1862
: 353
.
Clytia
osterudi
Strong, 1925
: 389
, pl. 37, hydroid.
Phialidium gregarium
. ‒
Murbach & Shearer, 1903
: 179, pl. 20. –
Kramp, 1961
: 167, 444. ‒
Kramp, 1962
: 25. –
Kramp, 1968
: 78, fig. 206. ‒
Roosen-Runge, 1970
: 217, figs. 2-25, hydroid. –
Arai & Brinckmann-Voss, 1980
: 104, figs 59-60.
Clytia gregaria
. –
Bouillon, 1995
: 233. ‒ Bouillon &
Barnett, 1999
: 99, fig. 101.
Material
examined:
Several
specimens;
USA
,
Friday Harbor Laboratories
, floating docks,
48.545141°N
123.012059°W
,
0.5 m
depth; collection date
23.05.2011
;
DNA
was isolated from two individuals,
DNA
920
giving the sequences 16S
MF000539
,
COI
MF000499
;
DNA
isolate 1169 yielding the 16S sequence
MF000540
. Specimens without black pigment; archived document see
Table 1
.
Diagnosis:
Umbrella up to
22 mm
wide, hemispherical to lens-shaped. Manubrium small, attached on a short gastric peduncle of variable height, manubrium base cross-shaped and attached to peduncle, mouth with 4 long, folded lips. Gonads linear, undulated, along distal half to two-thirds of radial canals, not touching circular canal; females with>
100 eggs
per gonad. Marginal tentacles 60-80, marginal bulbs nearly globular, few or no bulbs without tentacles when fully grown; l statocyst (or rarely 2 or 3) between successive tentacle bulbs, usually 1, sometimes 2 concretions per statocyst. Without colour or gonads pale yellow to salmon. With or without variable amounts of black or dark brown pigment on margin of lips, gonads, marginal bulbs and ring canal.
Distribution:
Shallow waters of coastal regions of the NE Pacific Ocean, from
British Columbia
to
Oregon
(
Arai & Brinckmann-Voss, 1980
).
Bouillon (1995)
and
Bouillon & Barnett (1999)
recorded it also from
New
Zealand
, mostly in deeper waters.
Type
locality: Strait of
Georgia
,
British Columbia
,
Canada
, Pacific Ocean.
Similar species:
Preserved and damaged material of this medusa can easily be confounded with
Eirene mollis
Torrey, 1909
(see
Arai & Brinckmann-Voss, 1980
for description).
Eirene mollis
has up to 180 tentacles and a somewhat more pronounced gastric peduncle. It is not known if it has excretory papillae.
Remarks:
A summary on the identity, taxonomy, biology, and distribution of this species is given in
Arai & Brinckmann-Voss (1980)
. This is a locally very common medusa. It has served for a large number of experimental studies (mostly using the superseded name
Phialidium gregariaum
,
e.g.
Dabiri
et al
., 2010
;
Freeman, 2005
;
Colin & Costello, 2002
;
Colin
et al
., 2003
;
Costello & Colin, 2002
;
Ridgway & Freeman, 1999
;
Mills, 1981
; and many more references given in these works).
Fig. 18.
Clytia gregaria
, bell diameter about 20 mm, after photographs of living specimens. (A) Lateral view. (B) Oral view. (C) Bell margin in oral view with three tentacles and 3 statocysts.
The hydroid of
Clytia gregaria
has been raised from the medusae several times but it was not possible to relate it to colonies sampled in nature (
Arai & Brinckmann-Voss,
1980
). The 16S and COI barcode sequence of the present material will hopefully help to identify its polyp stage in nature (
cf.
Schuchert
et al.
,
2017
).
Although rather shallow and sometimes absent, the gastric peduncle of
Clytia gregaria
is rather unusual for the genus
Clytia
and makes the medusa very prone to be mistaken for an
Eirene
species, e.g. the sympatric
Eirene mollis
Torrey, 1909
. Some
Eirene
species (
cf.
Schuchert,
2017
) with a shallow peduncle and no excretory papillae could thus turn out to be
Clytia
species.