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
Sphaerotylus bouryesnaultae
sp. nov.
Figures 77
a–e
Material examined.
Holotype
RMNH
Por. 6303,
Suriname
, ‘
Luymes O.C.P.S.
’
Guyana
Shelf Expedition, station K101B,
7.3783°N
54.3583°W
, depth
93 m
, rectangular dredge,
17 April 1969
.
Description.
(
Fig. 77
a) Globular individual of approximally
1.2 cm
in diameter, provided with a single conical papilla
6 mm
high
5 mm
in diameter. Color beige in alcohol. Upper surface surrounding the papilla has a ‘forest’ of individual long spicules (exotyles) protruding
2–3 mm
above the ectosome. Consistency firm.
Skeleton.
Similar to
Polymastia
, consisting of long subtylostyles radiating from the inner core to the surface, a subectosomal layer of intermediate-sized tylostyles arranged at right angles to the radiating subtylostyles, and a surface palisade of small tylostyles. Exotyles pass individually through the outer layers and protrude far beyond the surface.
Spicules.
(
Figs 77
b–e) Exotyles, subtylostyles, intermediate tylostyles, small tylostyles.
Exotyles (
Figs 77
b) provided with a tylote part with faint tyle (
Fig. 77
b1) at the inner end and a rugose elongate swelling at the outer end (
Fig. 77
b2), usually rather strongly curved; few of these exotyles could be retrieved undamaged, three measured
4–4.5 mm
x 8–12
µm, swollen rugose ends up to
45 x 10
µm.
Subtylostyles (
Figs 77
c,c1,c2), heads elongate with subterminal restricted part, fusiform, distinctly polytylote at the bluntly rounded end (
Fig. 77
c2), dominating the skeleton, 840–
1165
–
1458 x 13
–
17.8
–24 µm.
FIGURE 77.
Sphaerotylus bouryesnaultae
sp. nov.
, a, habitus of holotype RMNH Por. 6303 (scale bar = 1 cm), b–e, SEM images of spicules, b, exotyle details of both ends and middle part, b1, detail of tylote end, b2, detail of exotyle end, c, polytylote subtylostyle, b1, detail of upper end of c, c2, magnified details of c, d, intermediate tylostyle, d1, details of d, e, small ectosomal tylostyle, e1, details of e.
Intermediate tylostyles, distinct tyles, straight, ending thinly, 528–
718
–
1132 x 9
–
12.1
–16 µm.
Small tylostyles, globular tyle, usually curved, 105–
119
–147
x 3
–
3.9
–5 µm.
Distribution and ecology.
Guyana
Shelf, sandy bottom, at
93 m
depth.
Etymology.
Named after Dr. Nicole Boury-Esnault (Station Marine d’Endoume, Marseille) in acknowledgment of her important polymastiid studies and of her efforts to promote molecular approaches for the phylogeny of sponges.
Remarks.
This specimen represents the first record of the genus
Sphaerotylus
from the
Central
West
Atlantic. The exotyle spicules of the new species with their curved shaft and elongate exotyles appear distinct among all the known species. The genus was recently reviewed by
Plotkin
et al.
(2016a)
including the descriptions of three new species, but none of these were from the
Central
West
Atlantic region. Perhaps the closest species is
South
African
Sphaerotylus strobilis
Plotkin, Morrow, Gerasimova & Rapp, 2016
as it has the exotyle swellings also elongately irregular like in the present new species, but these exotyles are only up to 632 µm long in
P. strobilis
(against
4.5 mm
in the present species). Also the other spicules are distinctly different in size, whereas the shape differs with several papillae curved and ridged in
S. strobilis
. Elsewhere the genus is common in boreo-arctic waters (both in the North Atlantic and the North Pacific), and in Antarctic waters. Only a single record was so far known from the tropical zone,
S. exospinosus
Lévi, 1993
from
New Caledonia
, at
570–610 m
depth.