Digitate and capitate soft corals (Cnidaria: Octocorallia: Alcyoniidae) from Western Australia with reports on new species and new Australian geographical records
Author
Bryce, Monika
Author
Poliseno, Angelo
Author
Alderslade, Philip
Author
Vargas, Sergio
text
Zootaxa
2015
3963
2
160
200
journal article
10.11646/zootaxa.3963.2.2
6c08566c-16f7-4c32-a3c1-756725666467
1175-5326
288659
86A305B7-2B9C-403E-8FC0-3420EFB13F52
Paraminabea
cf.
aldersladei
Williams & Alderslade, 1999
(
Figs. 15
D,E,F, 17A,B; 18A,B; Tab. 2)
FIGURE 17.
Paraminabea
cf.
aldersladei
, WAM Z59783, sclerites: A, surface of the polyparium; B, interior of the polyparium.
FIGURE 18.
Paraminabea
cf.
aldersladei
, WAM Z59783, sclerites: A, surface of the base; B, interior of the base.
Material examined.
WAM
Z59783, five whole specimens, Station 44/K10, Long Reef, Kimberley, NW
Australia
,
13.92155° S
,
125.73268° E
, scuba, depth
10–20 m
, coll. M. Bryce,
20 October 2010
.
Description
. The colonies are either uniformly cylindrical from the base to the apical tip or are tapering toward the rounded apical end (
Fig. 15
D,E,F). They have a short, slightly laterally flattened polyp-free base. The polyps are dimorphic, and arranged uniformly over 60–90 % of the surface of the colonies. In all colonies the autozoids are completely retracted. The surface of the preserved specimens is extremely contracted and appears convoluted, which makes the siphonozooids difficult to locate. The gastric cavities of the autozooids form curved tubes (
Fig. 15
F). Colonies are between
16–24 mm
tall,
3–7 mm
in diameter at the apex and
5–7 mm
in diameter across the holdfast.
In the surface of the polyparium the sclerites are mostly 8-radiates and some cylindrical to oval forms,
0.04 to 0.09 mm
long (
Fig. 17
A), and in the interior the sclerites are double stars or double heads and irregular forms, some approaching crosses, from about
0.05 to 0.07 mm
long (
Fig. 17
B). The sclerites from the base are similar to those of the polyparium, consisting mostly of 8-radiates in the surface, from
0.06 to 0.08 mm
long (
Fig.18
A), and double heads or double-stars, with a long waist, together with irregular forms approaching crosses, up to
0.09 mm
long, in the interior (
Fig. 18
B). Polyp sclerites are absent.
Colour.
The colonies were uniformly dark red
in situ
and on deck. In alcohol the specimens are dark orange. The polyps in the preserved specimens are cream. The colour of the sclerites is red.
Habitat
. Very steep and fractured fore-reef slope ascending from 20 up to four metres depth. The slope is heavily pocketed with small caves and deep, steep-sided fissures. At 20 metres there are large rocky outcrops forming long-reef gullies, which are almost devoid of life, probably due to the heavy siltation. Sediment between the rocky outcrops is very fine and smothering. A small group of
Paraminabea cf. aldersladei
was found attached to the wall together with a group of
Eleutherobia kimberleyensis
sp. nov.
in an overhang at ten meters depth amongst other scattered soft corals.
Remarks.
Paraminabea cf. aldersladei
has similarities to
P. aldersladei
,
P. indica
,
and
P. robusta
.
It resembles
P. aldersladei
in growth form, but differs in
type
and distribution of the sclerites.
P. aldersladei
is bright orange and has mainly orange 8-radiates, double-heads, robust barrels and subspheroidal forms, while this species has red sclerites consisting predominately of radiates, double heads and complex cross-like forms.
Paraminabea indica
differs from
Paraminabea cf. aldersladei
by being dichromatic, the restriction of the polyps to less than half of the colony length, and the lack of tuberculated spheroids. It also appears to be restricted to deep water. The main differences between
P
.
cf. aldersladei
and
P. robusta
are colour, colony length and the morphology and distribution of the siphonozooids.