Species of Oswaldella Stechow, 1919 (Cnidaria: Hydrozoa: Kirchenpaueriidae) from US Antarctic expeditions, with the description of three new species
Author
Peña Cantero, A. L.
Author
Vervoort, W.
text
Journal of Natural History
2004
2004-04-10
38
805
861
journal article
1464-5262
Oswaldella encarnae
Peña
Cantero, Svoboda and Vervoort, 1997
(
figure 5
)
Oswaldella encarnae
Peña Cantero
et al
., 1997: 356–358
,
figures 4
,
13D
; Peña
Cantero and
García Carrascosa, 1998: 179; 1999: 214; Peña
Cantero and Vervoort, 1998: 36
; Peña
Cantero and Marques, 1999: 85
.
Material examined
.
002/009
, three fragments and stems up to
48 mm
high (USNM 1003310; RMNH-Coel. 30208).
Description
. Monosiphonic and unbranched stems up to
48 mm
high. Hydrocaulus provided with cauline apophyses directed upwards and forming an angle of
ca
45
°
with long axis of stem (
figure 5A
). This stem divided into internodes with one or two apophyses per internode. Cauline apophyses provided with two axillary nematophores, emerging through simple perisarc holes (
figure 5B, C
); without ‘mamelons’. Each apophysis supporting an unbranched hydrocladium (
figure 5
A–C), separated by a distinct node (
figure 5B, C
); top of distal hydrocladial internodes truncated.
Hydrocladia homomerously divided into internodes each provided with one hydrotheca and two nematophores (
figure 5
B–G): one infrathecal mesial nematophore with a scale-shaped nematotheca and situated on a slight elevation of internode, and one mesial superior nematophore, emerging through a perisarc hole placed behind free adcauline hydrothecal wall.
Hydrothecae usually placed on distal half of internodes (
figure 5
); sometimes in the middle (usually in basalmost internodes). Hydrotheca shallow, with part of the adcauline hydrothecal wall free. Abcauline wall straight, running smoothly into wall of internode under an angle of
ca
30
°
with internodal long axis. Aperture circular, slightly tilted downwards; rim even.
Gonothecae absent.
Ecology and distribution
.
Oswaldella encarnae
appears to be a shelf species, having been found from depths of
400 to 440 m
on muddy bottoms (Peña Cantero
et al.
, 1997); our material was found at a depth of
252 m
.
Peña Cantero
et al.
(1997) recorded gonothecae from February.
Presently
Oswaldella encarnae
can best be considered endemic to the Weddell Sea, in West
Antarctica
, as it has been reported off the south and east coasts of the Weddell Sea (Peña Cantero
et al.
, 1997). We record it here from north off Berkner Island, off the south coast of the Weddell Sea.