Reef sponges of the genus Agelas (Porifera: Demospongiae) from the Greater Caribbean
Author
Parra-Velandia, Fernando J.
Author
Zea, Sven
Author
Van Soest, Rob W. M.
text
Zootaxa
2014
3794
3
301
343
journal article
45859
10.11646/zootaxa.3794.3.1
8f255bd6-4072-4dfc-ab35-d233e0766ff3
1175-5326
285997
51852298-F299-4392-9C89-A6FD14D3E1D0
Agelas repens
Lehnert
& van
Soest, 1998
Fig. 9
Etymology from Latin, meaning to creep, to crawl.
Agelas repens
Lehnert
& van
Soest, 1998
: 83
,
Fig. 12
.
FIGURE 9.
Photographs of
Agelas repens
from Jamaica. A) Dry Holotype at ZMA. B) in situ, hanging from the wall of a reef slope crevice. C) Several freshly collected specimens; the scale represents 20 cm length and 0,5 cm width.
Material and distribution.
Holotype
examined at the Zoölogisch Museum Amsterdam (
ZMA
–
POR
12870), collected at reefs in front of the mouth of Río Bueno,
Jamaica
, on the ceiling of a cave,
23 m
depth. The material reviewed here includes only specimens from
Jamaica
also collected at the
type
locality (INV–
POR
1012, 1013, 1014).
This species seems restricted to
Jamaica
, so we consider this as a Greater Antilles species, but see remarks. Our specimens were found from
22 to 25 m
in depth, abundant at
23–
25 m
.
Description.
This species has a thin cord-like form (
Fig 9
A), sometimes found solitary (
Fig 9
B), branched or irregularly repent. The body hangs from a fleshy, patchy base, encrusted on walls and overhangs. Branches are up to
0.5 cm
in diameter and
30–50 cm
long; the base is up to
5 cm
by
8 cm
and
0.8 cm
thick. Its external colour is spectrum orange, internal colour orange yellow. It is compressible, flexible and elastic in life or preserved, still flexible when dry.
Oscules are tiny, almost invisible to the naked eye (<
2 mm
), surrounded by a star-like area where exhalant channels lead to them. Pinacoderm supported by tracts of spicules, collapses out of the water revealing a rough outline of subdermal channels (<
1 mm
) and other structures. Choanosome is apparently dense.
Skeleton of cored (2–7 spicules per cross section) primary fibres, loosely echinated, 20–50 Μm in diameter. When the coring spicules are absent fibres are hardly distinguishable; secondary fibres 20–30 Μm in diameter, poorly echinated; no tertiaries present. Acanthostyles are straight and long with 5–6 spines per whorl; length 88–268 (180±46.1) µm, width 3–13 (8±2.1) µm and 9–23 (16±4.1) whorls per spicule. Detailed lengths, widths and average number of whorls are shown in
Table 2
.
Remarks.
Agelas repens
is found hanging from walls on caves like long and thin cords. As far as we have explored, Rio Bueno is the only locality where this species is present. Lehnert & van
Soest (1998)
noted that this species is rather similar to some deep, thin specimens of
A. sceptrum
from
Barbados
(ZMA–POR
3811, 100 m
). Our specimens of
A. sceptrum
from Rosario Islands and San Andres Island are the ones most similar to
A. repens
. The differences in skeletal and spicule architecture and size are not enough to decide whether they are the same species, but the cryptic habit (or depth preference) and the resemblance in external morphology in
A. repens
and Belizean, Colombian and Barbadian
A. sceptrum
vs. the exposed habitat and thickly branched habit of typical
A. sceptrum
from
Jamaica
calls for synonymy. ITS and CO1 DNA analyses also placed
A. repens
together with
A. sceptrum
, but this is inconclusive as these species were also indistinguishable from
A. dilatata
,
A. conifera
,
A. tubulata
and
A. cerebrum
(
Parra-Velandia 2011
)
. However Jamaican
A. repens
were never thicker than
1 cm
, while Southern Caribbean
A. sceptrum
were rarely this thin.
Additionally, at the
type
locality we noted that the external colour and tissue texture of
A. repens
were very similar to those of
A. citrina
living nearby. We then had the idea that
A. repens
cords may be dispersive bodies of
A. citrina
. This hypothesis was reinforced by the fact that
A. repens
spicules in
Jamaica
were even longer that those of
A. citrina
, which usually has the longest spicules of all
Agelas
in several localities (
Table 2
). At any rate, the hypothesis of close relatedness between
A. repens
and
A. citrina
was discarded in the light of DNA studies (Parra-
Velandia, 2011
)