Sponges of the Guyana Shelf
Author
Van, Rob W. M.
text
Zootaxa
2017
1
1
225
journal article
37320
10.5281/zenodo.272951
e2c88f4c-3ac2-45f9-95e4-99b75561a081
1175-5326
272951
6D68A019-6F63-4AA4-A8B3-92D351F1F69B
Dragmaxia undata
Alvarez, Van Soest & Rützler, 1998
Figures 32
a–c
Dragmaxia undata
Alvarez, Van Soest & Rützler, 1998
: 26
, fig. 15;
Rützler
et al.
2014
: 71
.
FIGURE 32.
Dragmaxia undata
Alvarez, Van Soest & Rützler, 1998
, a, habitus of RMNH Por. 9821 (scale bar = 1 cm), b–c, SEM images of spicules, b, style, b1, details of b, c, raphides of trichodragma, c1, details of raphide apices.
Material examined.
RMNH
Por. 9821,
Suriname
, ‘
Snellius O.C.P.S.
’
Guyana
Shelf Expedition, station E66,
7.1°N
56.1783°W
, depth
65 m
, Agassiz trawl,
13 May 1966
.
Description.
Erect digitations (
Fig. 32
a) on a cushion-shaped basis attached to a dead shell. Height of specimen
4 cm
, dimensions of the two digitations
1–1.5 cm
high and
0.5 cm
diameter. Surface irregular, encrusted with bryozoans, microhispid, semitransparent, whitish-yellowish in color (alcohol preserved). Consistency firm.
Skeleton.
This consists of largely confused single styles, but vague tracts of spicules are directed upwards into the digitations. Styles partially penetrate the surface.
No
visible spongin. Many open spaces. Straight, or more frequently, wavy trichodragmas are numerous between the styles.
Spicules.
(
Figs 32
b–c) Styles, trichodragmas.
Styles (
Fig. 32
b,b1), slightly to strongly curved, seldom straight, more or less equidiametrical over much of their length, sharply pointed, 690–
893
–
1046 x 13
–
19.2
–26 µm.
Trichodragmas (
Figs 32
c,c1), curved and wavy, seldom straight, raphides provided at both ends with one or two hook-like spines (
Fig. 32
c1), 184–
220
–258
x 4
–
6.4
–9 µm.
Distribution and ecology.
Guyana
Shelf,
Curaçao
,
Bonaire
, Colombian Caribbean,
Belize
, in cryptic reef habitats and at greater depth on shelly slopes, at
0.5–65 m
depth (previously down to
35 m
).
Remarks.
The present specimen differs in shape from the
type
material and from the
Belize
material, as these were basically encrusting. However, the digitate shape clearly developed from an encrusting base, so it may merely represent a more developed form in a habitat with less competition. Spicule shapes and sizes conform closely to the
type
material. The
Belize
material apparently had trichodragmas up to 600 µm, considerably longer than trichodragmas in the
type
material and the
Guyana
material.