Some hydrozoans (Cnidaria) from Central Chile and the Strait of Magellan
Author
Galea, Horia R.
Author
Schories, Dirk
text
Zootaxa
2012
3296
19
67
journal article
10.5281/zenodo.280882
e115374e-5859-427c-b28f-74d469b2cf3a
1175-5326
280882
Halecium annuliforme
sp. nov.
(fig. 2F–M, table 1)
Halecium
sp. Galea, 2007: 59, fig. 13E, F.
Halecium annulatum
—
Jäderholm, 1920
: 2
, pl. 1 figs 2, 3. (not
H. annulatum
Torrey, 1902
: 49
, pl. 3 figs 30, 31).
Halecium delicatulum
—
Blanco, 1968
: 203
, pl. 1 figs 14–18, pl. 2 figs 1–3. (not
H. delicatulum
Coughtrey, 1876
).
Material examined
.
Stn. FSI
—
04.i.2011
, S10 (
40 m
): numerous minute sterile stems arising from hydrorhiza creeping on
Parascyphus repens
.
Stn. PAR
—
07.i.2011
, S08 (
15 m
): a single, sterile stem, epizoic on
Halecium pallens
.
Holotype
— Swedish Museum of Natural History, no. 8214 (old no. 599, general catalogue), Lennox
Island
, 15–20 fathoms, on seaweed.
PLATE
2
. A–E:
Staurocladia vallentini
(
Browne, 1902
)
—exumbrellar (A–C, E) and subumbrellar (D) views of the medusa; cross section through a medusa stained with Grenacher's alcoholic borax-carmine (insert A). F–H:
Samuraia tabularasa
Mangin, 1991
—group of polyps and their movements during foraging.
Remarks
. This hydroid has been described previously, as
Halecium
sp., by Galea (2007).
As
with his specimens, material examined here is unfortunately sterile. Colonies from both studies bear a striking resemblance to hydroids from Lennox
Island
assigned by
Jäderholm (1920)
to
Halecium annulatum
Torrey, 1902
. His material, in collections at the Swedish Museum of Natural History (SMNH #8214 7), was re-examined to determine whether it is conspecific. Jäderholm’s hydroid comprises a small colony growing on seaweed, with a dozen stems (some unbranched, some sparingly-branched), up to
3 mm
high, and four gonothecae. The stems are morphologically indistinguishable from those in our material (compare fig. 2F and G), except for somewhat thicker perisarc. A pseudodiaphragm is present in some hydrothecae but absent in others (fig.
2I
). Gonothecae are small, stolonal, borne on rather long pedicels, lenticular in shape with a circular aperture, and with slightly thickened perisarc. Some contain a few spherical eggs,
ca
. 50 µm in diameter (fig. 2L). The stout habit of the colony, as well as hypertrophy of its perisarc, may be due to continual movement of its algal substrate.
Jäderholm's hydroid appears clearly different from Torrey's (1902) species in the following respects: 1) branching is spare and very irregular, while specimens of the latter had "regularly alternating branches"; 2) the internodes of the former are slender, very irregular and long, while
H. annulatum
forms rather short internodes giving rise to "hydrothecae alternately on either stem or branch"; 3) the hydrothecae of the former are borne on primary hydrophores varied in length, and are definitely sessile in Torrey’s species.
The hydroid from Lennox
Island
, misidentified earlier as
Halecium annulatum
, is designated as
holotype
of
Halecium annuliforme
sp. nov.
Our specimens, and those of Galea (2007), are referred to this new species. Moreover, the description and figures of a hydroid assigned by
Blanco (1968)
to
H. delicatulum
Coughtrey, 1876
leave little doubt that it is conspecific.
TABLE 1
. Comparative measurements of
Halecium annuliforme
sp. nov.
, in µm.
|
References
|
As
H. annulatum
Torrey, 1902
, SMNH #8214
Jäderholm (1920), present study
|
As
H. delicatulum
Coughtrey, 1876
Blanco (1968)
|
H. annuliforme
sp. nov.
Galea (2007), present study
|
|
Colony
- maximum height
|
5000 |
5000 |
3000 |
|
Stolon
– diameter
|
– |
74–129 |
79–97 |
|
Internodes
|
| – length |
– |
294–497 |
– |
| – diameter |
94–112 |
74–110 |
65–130 |
|
Hydrotheca
|
| – depth |
50–105 |
55–92 |
55–95 |
| – diameter at rim |
150–255 |
166–221 |
175–270 |
| – diameter at base |
95–150 |
– |
85–140 |
|
Female gonotheca
|
| – length |
860–900 |
810–994 |
– |
| – maximum width |
540–700 |
515–662 |
– |
| – egg number |
8–10 |
– |
– |
Stout species of
Halecium
with wrinkled stems and branches resembling
H. annuliforme
include:
H. corrugatissimum
Trebilcock, 1928
,
H. corrugatum
Nutting, 1899
, and
H. textum
Kramp, 1911
. However, gonothecae of these species are different: those of
H. corugatissimum
are transversely ridged and provided with a
7. This sample also contains two other haleciids, each represented by a several millimeter high fragment. One of these is sterile and could be provisionally assigned to
H. jaederholmi
Vervoort, 1972
(fig. 2N), the other bears male gonothecae and is unidentifiable (fig. 2
O
). If these additional species were originally present in sample #8214 and are not the result of a subsequent contamination, the finding of
H. jaederholmi
at Lennox
Island
represents the first record of this species from
Chile
. For a full list of distribution records, see
Peña Cantero (2008)
.
pair of protruding hydranths (
Schuchert 2005
); those of
H. corrugatum
are urn-shaped with a large apical aperture (see
Fraser 1914
); and those of
H. textum
are ovoid, less compressed laterally, and distally truncate at the aperture (
Schuchert 2005
).
Etymology
. The specific epithet refers to the annulated shape of the stems and branches.
Distribution in
Chile
. Lennox
Island
(
Jäderholm 1920
, as
Halecium annulatum
Torrey, 1902
), Camello
Island
(Galea 2007, as
Halecium
sp.), Strait of Magellan (present study).
World records
.
Isla
de los Estados,
Argentina
(
Blanco 1968
).