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
Lycopodina brochidodroma
sp. nov.
Fig. 31
,
Table 14
urn:lsid:zoobank.org:act:
8A142BA5-58F2-4556-BFAA-3AC717724C76
Material Examined:
Holotype
QM
G337540
, off
Moreton Island
,
Station
103,
Queensland
,
Australia
, 27° 0’ 1.1”–
27° 3’ 39.6” S
, 154° 13’ 22.8”–
154° 13’ 22.8” E
,
4260–4280 m
,
Brenke Epibenthic Sledge
,
Coll. Merrick Ekins
on
RV
Investigator
, Cruise IN2017_
V03
,
Sample
103-122,
10/vi/2017
.
Etymology
:
brochis
, Gr. inkhorn,
apodrome
, Gr.
f.
running from, divergence. Named after the species’ body shape that is reminiscent of a particular vein-like pattern found in some leaves, i.e. brochidodromous, of a leaf nerve: forming loops.
Distribution
: This species is presently known only from
type
locality off Moreton Island,
Queensland
, at abyssal depth.
Description:
Growth form
: The sponge consists of an erect central axis with long lateral filaments on opposite sides, alternating every second row, so that the sponge has four columns of filaments (
Figure 31 A
). The filaments (presumably due to the epibenthic dredge) emerge at almost right angles from the axis (
Figure 31
G–H), but then curve through 90 degrees, and are then arranged in an almost parallel arrangement to the axis. This gives rise to the appearance of the veins in a leaf. The sponge is only
20 mm
in length, and
1 mm
in width including the folded filaments. The central axis is only
0.25 mm
in width and the filaments, excluding the buttressed attachments, narrow from
90 µm
down to a blunt point of about
20 µm
. The specimen has been broken so it is not possible to determine the original length, nor the attachment structures. The entire sample is now embedded on SEM stubs.
Colour
: White in ethanol.
Ectosomal skeleton
: The ectosomal skeleton is thin and membranous and contains the palmate anisochelae (
Figure 31
H–I).
Endosomal skeleton
: The axis consists of mycalostyles and secondary subtylostyles in longitudinal bundles (
Figure 31 H
). Subtylostyles occur as supporting structures where the filaments attach to the main axis.
Megascleres:
Oxeote mycalostyles with long tapering points, slightly sinuous shaft with largest diameter at the centre of the spicule, and with evenly rounded bases (621-(1364)-
1816 x
7.4-(19.4)-32.7 μm, n=17) (
Figure 31
C–D). Subtylostyles straight or slightly curved, with tyle slightly subterminal from the base (202-(285)-328 x 3.6- (5.4)-
7.8 µm
, n=26) (
Figure 31
E–F).
Microscleres
: Palmate anisochelae of a single size class, with the three upper alae smooth, palmate, with the frontal alae partly fused to the lateral alae for about 50% of its length, lateral alae completely fused to the fimbria, and the three lower alae fused, arcuate, with the frontal one with three spines and the two lateral alae each with two spines (10.7-(12.9)-15.2 x 2.4-(3.3)-4.9 μm (upper alae width) x 2.8-(3.4)-4.2 μm (lower alae width), n=107) (Fig- ure 31 B).
Molecular data
: Nil
Remarks
: Although the growth form of this sponge appears to be quite similar to
Asbestopluma biseralis
(
Ridley & Dendy, 1886
)
, depicted in
Ridley & Dendy (1887
, Pl. XIV) and
Lévi (1964
, Pl. III H), it differs in having the double lower teeth of the anisochelae, placing it in
Lycopodina
, lacking the small contort sigmas, and having smooth, not spined subtylostyles found in
A. biserialis
.