New dendrochirotid sea cucumbers from northern Australia (Echinodermata: Holothuroidea: Dendrochirotida)
Author
P. Mark O’Loughlin
Author
Melanie Mackenzie
Author
Didier Vandenspiegel
text
Memoirs of Museum Victoria
2014
2014-12-31
72
5
23
journal article
29824
10.5281/zenodo.1298027
b234abf6-4127-4bbe-a4da-07eb7316d36b
1447-2554
1298027
DDB03260-10B7-47A5-9F34-41EE360CBA68
Actinocucumis
Ludwig, 1875
Actinocucumis
Ludwig, 1875: 91
.—
Théel, 1886
: 125.—
H. L. Clark, 1946
: 402–403.—
Heding and Panning, 1954
: 70–72.—
A. M. Clark and Rowe, 1971
: 204.
Figure 9. Photos of live and preserved specimens of
Triasemperia
stola
O’Loughlin
sp. nov.
A, lateral view of live holotype specimen (mouth right; NMV F174889); B, lateral view of preserved holotype (mouth right, lateral view width 45 mm); C, lateral view of preserved paratype (mouth right, lateral view width 50 mm, NMV F204088); D, photo of the calcareous ring of the holotype; insert with sketch of the calcareous ring.
Type
species.
Actinocucumis typica
Ludwig, 1875
(
type
locality
Queensland
, Bowen, 20°S 148°E)
Other species and
type
localities
.
Actinocucumis chinensis
Liao and Pawson, 2001
(off
Hainan
,
South
China
Sea
)
;
A. cornus
(
Heding, 1934
)
(Hong Kong);
A. difficilis
Bell, 1884
(Torres Strait, north-east Australia);
A. longipedes
Clark, 1938
(Broome, north-west Australia);
A. simplex
(
Sluiter, 1914
) (Indonesia)
;
A. solanderi
O’Loughlin
sp. nov.
(off
King George River
, northern
Australia
) (see below).
Remarks
.
Heding and Panning (1954)
listed numerous synonymies for
Actinocucumis typica
, with lengthy discussion. We have not examined the relevant
type
specimens but based on the figures and descriptions in the literature, and on our
sensu stricto
diagnosis of
A. typica
below, we raise all of these species out of synonymy.
We note that in discussing their synonymies
Heding and Panning (1954)
observed in their slide preparations from
Actinocucumis typica
and
Actinocucumis cornus
specimens small elongate plates with two long mid-plate perforations and two small distal ones. This form of ossicle was illustrated by
H. L. Clark (1938)
for
Actinocucumis longipedes
. Ludwig (1875) did not illustrate this form of ossicle and we have never observed such ossicles in our preparations from specimens of
A. typica
from the region of the type locality and across northern Australia. It appears to us that Heding and Panning were not examining specimens of
A. typica
.
Two ossicles are drawn for
Actinocucumis typica
in
Clark and Rowe (1971
; fig. 95 e and e’). We have seen only the left hand side form (e) in the specimens of
A. typica
that we have examined, and this is the only form in the original description by Ludwig (1875). The right hand side form (e’) appears to be typical of
Actinocucumis longipedes
and was referred to by
Heding and Panning (1954)
above. The two ossicle forms appear to have been drawn from a specimen of
A. longipedes
.
Figure 10. SEM images of ossicles from the holotype of
Triasemperia stola
O’Loughin
sp. nov.
(NMV F174889). A, mid-dorsal body wall tables, spires with 3 pillars (scale bars 20
µ
m); B, peri-anal body wall tables (scale bars 20
µ
m); C, tube foot tables (scale bars 20
µ
m); D, tentacle rods (scale bars 20
µ
m).
We note that the
Clark and Rowe (1971)
illustration of ossicles from
A. typica
(pl. 30 fig. 4) is in fact from a
type
specimen of
Actinocucumis difficilis
Bell
that was judged to be a con-specific with
A. typica
. The ossicles appear to us to exemplify
A. typica
, and that adds weight to the probability of a synonymy (NHMUK
type
information confirmed by Andrew Cabrinovic). There are no small elongate plates with two long mid-plate perforations and two small distal ones in this preparation.
The single
type
specimen from
Hong Kong
of
Phyllophorus cornus
Heding, 1934
has tube feet all over the body, five inner tentacles and 15 outer, and five anal teeth. Ossicles from the
type
of
Actinocucumis cornus
were used for the illustration in
Heding and Panning (1954, fig. 19)
of the ossicles of
A. typica
. The original illustration of ossicles for
A. cornus
(
Heding 1934
)
did not show fenestrated ellipsoids. That in
Heding and Panning (1954)
did show fenestrated ellipsoids. Neither illustrated the small plates with two long and two small distal perforations that
Heding and Panning (1954)
indicated were present. We judge that the status of
A. cornus
as conspecific with
A. typica
remains uncertain, and we raise it out of synonymy as an
Actinocucumis
species.
Pseudocucumis quinqangularis
Sluiter, 1901
from
Indonesia
has posterior prolongations on the radial plates of a composite calcareous ring, 12 large outer and six small inner tentacles, and an absence of figure-8 ossicles and fenestrated ellipsoids. It is not a species of
Actinocucumis
and we raise the species out of synonymy in the original combination to await further study.
The single small type specimen from Ceylon of
Actinocucumis donnani
Pearson, 1903
does not have the tentacles present, has a composite calcareous ring with long posterior prolongations on the radial plates, and has body wall ossicles that are not fenestrated ellipsoids or any form of table. It is not an
Actinocucumis
species. In the absence of tentacles it is not possible to re-assign the species that we regard as
incertae sedis
.
The illustrations for
Phyllophorus simplex
Sluiter, 1914
indicate ossicles that do not include fenestrate ellipsoids and typical figure-8 plates, and the description reports tube feet covering the body. It is not conspecific with
Actinocucumis typica
,
and we raise it out of synonymy with reservations as an
Actinocucumis
species.
H. L.
Clark (1938
,
1946
) examined numerous specimens of
Actinocucumis
from northern
Australia
and was convinced of the existence of four species:
A. typica
,
A. difficilis
,
A. longipedes
,
A. quinuangularis
. We reject
A. quinuangularis
as an
Actinocucumis
species (above), but accept the judgment by Clark who recognized the other three species. We raise
A. difficilis
and
A. longipedes
out of synonymy here. In the case of
A. difficilis
we defer to the experience of H. L.
Clark (1938
,
1946
) who had an abundance of material to examine, but we also judge that the morphological characters that he used to distinguish this species are probably variable characters. We think that a confirmed synonymy requires more consideration. The presence in
A. longipedes
of small elongate plates with two long mid-plate perforations and two small distal ones is apparently systematically distinctive.
We note the absence of fenestrated ellipsoids and radial papillae in
Actinocucumis chinensis
and continue to refer this species to
Actinocucumis
with reservation, as did
Liao and Pawson (2001)
.