A guide to the deep-water sponges of - NMFS Scientific Publications ...

15. Acanthascus (Staurocalyptus) solidus (Schulze, 1899)
Description. This compressible but very spiny sac
or vasiform sponge attaches basally to hard substrate.
External surface is covered by a dense veil of projecting
pentactins in amongst the long prostal diactin needles,
with a single large terminal osculum bordered by a
marginal fringe of diactins. Consistency is soft but spiky.
Height is to 24 cm, diameter to 15 cm, and 23 mm in
wall thickness. It may be found in clusters of up to nine
individuals. Color in life is white but sometimes coated
with sediment, epizoic organisms, and flocculent material,
giving it a brown to greenish brown appearance;
drab when preserved.
Skeletal structure. Skeleton is composed entirely of
loose spicules. Megascleres are thick prostal diactins to
4 cm long; hypodermal pentactins all have smooth or
shagreened (never thorned) tangential rays (1.8–6.6
mm long) and smooth proximal rays (5.5–9.6 mm
long); principal diactins (2.0–8.4 mm long); dermal
stauractins (75–180 mm ray length), dermal pentactins
with tangential rays (88–193 mm long) and proximal
rays (88–163 mm long); atrial hexactins (89–134 mm
ray length). Microscleres are oxyhexasters and oxyhemihexasters
(113–179 mm in diameter); discoctasters with
straight terminals (134–225 mm in diameter); microdiscohexasters
(16–22 mm in diameter).
Zoogeographic distribution. North Pacific Ocean.
Locally abundant. In Alaska – eastern Gulf of Alaska.
Elsewhere – British Columbia to southern California
(Santa Maria Basin).
Habitat. In Alaska – attached to bedrock, cobbles, and
pebbles at depths between 82 and 255 m. Elsewhere –
reported at depths between 91 and 1373 m.
Remarks. Acanthascus solidus can be distinguished
from the sometimes similar A. (R.) dawsoni dawsoni by
its complete lack of thorned hypodermal pentactins
that are always present and heavily thorned in the latter
species. In the central Aleutian Islands a very similar
species (possibly Acanthascus solidus but not confirmed)
occurs at depths between 399 and 463 m. This species is
preyed upon by the sea stars Hippasteria spp., Poraniopsis
inflata, and possibly Henricia longispina in the eastern
Gulf of Alaska.
Photos. 1) Mostly intact specimen collected at a depth
of 167 m in the eastern Gulf of Alaska. Grid marks are
1 cm 2 . 2) Specimen (indicated by the white arrow) at a
depth of 165 m in the eastern Gulf of Alaska.
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