Additions to the aspidochirotid, molpadid and apodid holothuroids (Echinodermata: Holothuroidea) from the east coast of southern Africa, with descriptions of new species
Author
THANDAR, AHMED S.
text
Zootaxa
2007
2007-03-01
1414
1
1
62
http://dx.doi.org/10.11646/zootaxa.1414.1.1
journal article
10.11646/zootaxa.1414.1.1
11755334
5077005
DC93A9BC-D24E-44AD-99AF-79CACCCFB984
Holothuria
(
Thymiosycia
) cf.
arenicola
Semper, 1868
Figure 20
Holothuria arenicola
Semper, 1868:81
, 277, p1.20, pl.30: fig.13, p1.35: fig.4.
Holothuria (Thymiosycia) arenicola
Cherbonnier, 1988:82
, fig. 32 (synonymy before 1988), Samyn, 2003:81 (synonymy & records to 2003).
Previous southern African record
Mozambique
.
Material examined
Mission Rocks
,
KZN
,
12 vii 1968
,
A.S. Thandar
,
1 spec.
; Isipingo Beach,
KZN
,
20 vii 1970
,
A.S. Thandar
,
1 spec.
(juvenile); Treasure Beach, Durban,
KZN
,
2 vii 1974
,
F.L. Farquharson
,
1 spec.
; Park Rynie,
KZN
,
20 iii 1981
,
K.S. Ganga
,
1 spec.
(
All
above materials currently in the
Royal
Belgium
Institute of Natural Sciences
,
Brussels
);
Treasure Beach
(
KZN
),
1 spec.
, (as
H. (T.) conusalba
, deposited in the
Australian Museum
under AM
J20197
)
.
Description
Specimens cylindrical, vermiform or cigar-shaped, largest
100 mm
. Dorsum in life, mottled greyish white to beige to a mottled greyish brown, always with 8–9 pairs of dark greyish-brown or rust-coloured blotches, decreasing in intensity posteriad, ventrum greyish white to brown, skin around anus sometimes rust-coloured. Podia either in the form of only tubefeet, then papillae restricted to anus, or podia papilliform dorsally and as tubefeet ventrally. Water ring usually situated far behind level of calcareous ring. Cuvierian tubules present. Tables of body wall with smooth, circular to quadrangular disc,
50–70 µm
, with four central and four or more smaller marginal holes, a stout spire with single cross-bar, terminating in a squarish crown of 12–15 teeth, some larger table discs with five central and up to 14 smaller marginal holes. Buttons thick,
50–80 µm
, nearly always regular with smooth to gently undulating margins and 3–4 (sometimes 6) pairs of holes, and occasionally with two poorly defined central knobs, often difficult to demonstrate. Because of the thickness of buttons and the funnel-like shape of the holes, the latter may appear small or large depending on the focal point of the objective.
Local distribution
KZN
,
South Africa
, as far south as Park Rynie.
FIGURE 20.
Holothuria (Thymiosycia)
cf.
arenicola
Semper. Treasure Beach. A.
Tables from dorsal body wall; B. buttons from dorsal body wall; C. table from ventral body wall (side view); D. buttons from ventral body wall; E. tubefeet rods; F. rods from tentacle stalk; G. part of calcareous ring. (A & E scale a)
General distribution
H.(T.) arenicola
(se) almost circumtropical.
Habitat
In sand, under rock ledge or between sandstone slabs.
Remarks
The colour of this species is variable, probably depending to some extent on the immediate habitat. Apart from the normal coloured individuals, rust-coloured specimens were also described by
Fisher (1907)
,
Deichmann (1958)
and
Pawson (1976)
and black individuals by
Pawson (1976)
. It is because of this and the form of the spicules the specimens are here tentatively referred to
H. arenicola
. Although cuvierian tubules are said to be present in
H. arenicola
,
Pearson (1913)
reports their absence in his specimen from
Sri Lanka
. The dimensions of the spicules here given correspond well with those given for the species by
Fisher (1907)
,
Pawson (1978)
and to some extent
Rowe (1969)
. Amongst the tropical Indo-West Pacific species of
Thymiosycia
, only
H. macroperona
and
H. strigosa
have buttons greater than
65 mm
(see
Rowe 1969
) but in these species the table discs are
65–80 µm
with eight marginal holes and the holes of the buttons large.
H. (T.) arenicola
was first discovered in
South Africa
by the writer but these records were not published (see
Thandar 1971
,
1984
). Dr Cherbonnier, to whom a specimen was initially sent for confirmation of identification, thought that it represented
H. hilla
. The writer has since examined
H. hilla
from both
Mauritius
and
South Africa
and is forced to disagree with Dr Cherbonnier. This opinion is supported by Dr Rowe (pers. comm.). The current specimens are so typical of
H. (T)
arenicola
as described by other writers, notably
Pearson (1913)
, Panning (1934),
Deichmann (1930
,
1958
) and
Pawson (1976
,
1978
), that they cannot be referred to another species. Dr Rowe (pers. comm.) is of the opinion that the specimens may represent
H. (T.) conusalba
Cherbonnier
from
New Caledonia
. I hate to disagree with Dr. Rowe and in this I am supported by Dr Samyn (pers. comm.). In fact, both Dr Samyn and I are of the opinion that these specimens and a few others also collected from the
KZN
coast by Dr Samyn himself but as yet undescribed, may represent either
H.(T.) milloti
Cherbonnier, 1988
or a new species. The current material differs from
H. milloti
in the absence of anal valves, pseudobuttons amongst the body wall spicules and plate-like spicules in the dorsal podia. Recently Drs Samyn and Massin have begun a revision of
H. (T.) arenicola
complex of species on a world-wide basis and the correct identity of the South African material, now in
Belgium
, must await the outcome of this or some other revision.