Benthic hydroids (Cnidaria, Hydrozoa) from bathyal and abyssal depths of the Northeast Atlantic held in the modern Discovery Collections
Author
Peña Cantero, Álvaro L.
Author
Horton, Tammy
text
Zootaxa
2017
2017-11-10
4347
1
1
30
journal article
31577
10.11646/zootaxa.4347.1.1
49a11228-6c4d-478f-b958-52610eaab951
1175-5326
1044772
176D72B0-0DD6-4D51-83CA-D47C2268A3CF
Clytia gigantea
(
Hincks, 1866
)
(
Fig. 5A–B
)
Campanularia
gigantea
Hincks, 1866
: 297
; 1868: 174, pl. 35 fig. 1;
Jäderholm, 1909
: 69
, pl. 7, figs 1–3;
Christiansen, 1972
: 293
.
Clytia gigantea
—
Hirohito, 1995
: 61
–63, fig. 18a, b;
Vervoort & Watson, 2003
: 418
, 419, fig. 102J;
Calder, 2012
: 46
–47, figs 46–47.
Material examined. 51103#5
, one stem
13 mm
high and two extra hydrothecae, no gonothecae.
Description.
The 13-mm-high stem is provided with three hydrothecae (two of them broken). The isolated hydrothecae are provided with a very long pedicel. Hydrotheca elongate, roughly cylindrical in distal half, tapering in basal half (
Fig. 5A
). Rim of hydrothecal aperture with eight to 13 cusps, with smoothly curved distal part, curved inwards, and separated by deep, rounded embayments (
Fig. 5B
).
Measurements (in µm).
Hydrotheca
: height 1100–2000, diameter at aperture 400–840, diameter at diaphragm 100–140, height of basal chamber 40–100.
Remarks.
The two isolated hydrothecae are distinctly smaller (1100–1240 high and
400–460 in
maximum diameter) than the undamaged one of the branched stem (2000 high and
840 in
maximum diameter).
Calder (2012)
also found hydrothecae exceeding 2000 µm in length in his material and
Christiansen (1972)
even reaching 3000 µm.
The gonotheca of this species was recently described by
Calder (2012)
.
As indicated by other authors (e.g.
Calder 2012
) this species is easily recognizable by the large size of the hydrotheca, as well as by the shape of the hydrothecal cusp (linguiform
sensu
Calder 2012
).
According to
Calder (2012)
, reports of this species from the Mediterranean and the Atlantic and Pacific coasts of North America need confirmation. The species has also been reported from Chile (
Leloup 1974
;
Galea
et al.
2009
), but
Galea & Schories (2012)
indicated that Leloup’s record was based on a misidentification and that the attributable record by
Galea
et al.
(2009)
was also erroneous.
Ecology and distribution.
This species was found at depths between 20 (
Calder 2012
) and
512 m
(
Vervoort & Watson 2003
); the present material comes from
930 to 950 m
, extending its lower bathymetric limit.
According to
Calder (2012)
,
Clytia gigantea
is distributed for the boreal waters of the North Atlantic. However, the species has also been reported from Japanese waters (
Hirohito 1995
) and from the Chatham Islands region, in the South Pacific (
Vervoort & Watson 2003
). Our material comes from the Porcupine Seabight.