Carnivorous sponges from the Australian Bathyal and Abyssal zones collected during the RV Investigator 2017 Expedition
Author
Ekins, Merrick
Author
Erpenbeck, Dirk
Author
Hooper, John N. A.
text
Zootaxa
2020
2020-05-12
4774
1
1
159
journal article
22182
10.11646/zootaxa.4774.1.1
269cf599-428d-464d-8f21-994d69110c5c
1175-5326
3825140
B0C4A2F8-F2AB-4147-BB12-63720EEF2516
Abyssocladia annae
sp. nov.
Figure 4
,
Table 1
urn:lsid:zoobank.org:act:
E572DF22-EF0F-406D-B053-C20C0A5F84EA
Material Examined
:
Holotype
:
QM
G337611
, off the continental shelf of central
New South Wales
,
Australia
,
Station
88, 30° 15’ 50.4”–
30° 17’ 12.2” S
, 153° 52’ 12”–
153° 49’ 48.7” E
, 4481–
4401 m
,
Beam Trawl
,
Coll. Merrick Ekins
on
RV
Investigator
, Cruise
IN2017_
V03
,
Sample
88–141.1
6/vi/2017
.
Etymology
: Named after the loving memory of Anne Ekins and Anna
Nelson
, both of whom instructed the senior author about the beautiful design in nature.
Distribution
: This species is currently known only from the central coast of
New South Wales
,
Australia
, at abyssal depth.
Description:
Growth form
: The
holotype
consists of the remains of a stem supporting a slightly cupped obovate (leaf-like, flabellate, fan-shaped) apical body (
Figure 4 F
). The body is hispid, with bundles of spicules radiating out only over a 90° quadrant. The specimen is
3 mm
long x
2 mm
wide.
Colour
: Beige on deck and beige in ethanol.
Ectosomal skeleton
: Thin membranous layer encrusted with abyssochelae.
Endosomal skeleton
: The axis of the stem consists of longitudinally arranged subtylostyles. The main body consists of radiating bundles of subtylostyles, undifferentiated from those of the stem.
Megascleres:
Subtylostyles are long and straight, thickest in the centre with a sharp tip (288-(504)-
1000 x
3.1- (7.4)-15.2 μm, n=49).
Microscleres
: Abyssochelae isochelae with obvious ridge and curved triangular shaft. (48.2-(60.6)-72.2 x 5.1- (9.7)-14.9 μm, n=45). Sigmancistras (11.6-(15.6)-18.5 x 0.9-(1.3)-1.8 μm, n=54).
Molecular data:
It was not possible to get unambiguous molecular data from the
type
material.
FIGURE 4.
Abyssocladia annae
sp. nov.
A. Abyssochelae. B. Subtylostyle. C. Magnified ends of the subtylostyle depicted in B. D. Sigmancistra. E. Holotype QM G337611. F. SEM showing the abundant abyssochelae and sigmancistras in the ectosome and the underlying subtylostyles in the endosome.
Remarks
: The shape of this species resembles one of the distal ends of the branches of
A. koltuni
Ereskovsky & Willenz, 2007
from the Sea of Okhotsk. However,
A. annae
sp. nov.
lacks the large filament-forming mycalostyles that radiate from the oval bodies of
A. koltuni
, and also differs in lacking sigmas and having only a single size class of abyssochelae, which presents a very different shape to the isochelae of
A. koltuni
(
Table 1
). The gross morphology of this new species also superficially resembles that of the distal parts of
A. hemiradiata
Hestetun
et al.
, 2017a
from the SW Indian Ocean Ridge, but differs in having the slightly cupped morphology, with mainly bundles of subtylostyles radiating in one quadrant only.
Abyssocladia annae
sp. nov.
also lacks the larger and thicker styles and the sigmas of
A. hemiradiata
, and has much larger sigmancistras (
Table 1
). Most obvious in this new species is the much larger and highly ridged abyssochelae. The only other
Abyssocladia
with similar chelae is
A. brunni
Lévi, 1964
from the Kermadec Trench.
Abyssocladia annae
sp. nov.
differs in morphology from
A. brunni
which has a stem supporting a pedunculate spherical body heavily echinated by large lateral filaments up to
13 mm
in length, as described both in
Lévi (1964)
and
Koltun (1970)
. In addition, the current species also has smaller isochelae of a different shape (which
Lévi 1964
terms ‘thaumatochetes’), sigmancistras only half the size, and smaller subtylostyles than those of
A. brunni
. In addition,
A. brunni
has styles, with only few showing slight subtylote basal swelling. The two known specimens of
A. brunni
described by
Lévi (1964)
and
Koltun (1970)
are possibly two different species.
Abyssocladia annae
sp. nov.
also differs from
A. natushimae
Ise & Vacelet, 2010
from the Izu-Ogasawara Arc, in lacking filaments that echinate the main body, and the absence of styles, strongyles, and substrongyles and microstrongyles found in the Japanese species (
Table 1
).