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

9. Aphrocallistes vastus Schulze, 1886
Description. Basic form is a hollow, thin-walled cone,
but larger, older specimens add lateral mitten-like outgrowths
becoming highly variable; overall it is similar to
Heterochone calyx with which it is often confused. Surface
is smooth, usually with a single large terminal osculum.
Consistency is rigid and brittle. Size is up to 2 m high
and 3 m laterally. Color in life varies from white to light
yellow and orange.
Skeletal structure. SEM images of spicules are shown
in Appendix IV. Rigid skeleton of fused hexactinal spicules
has distinctive honeycomb pattern of 1 mm wide
channels. Several types of loose megascleres include
dermal pinular hexactins with pinulus (109–185 µm
long), tangential rays (38–142 µm long), proximal ray
(53–232 µm long); small hexactins (85–201 µm/ray);
scopules on both surfaces (262–497 µm long); atrial
spiny diactins (262–722 µm long); uncinates (890–3440
µm long). Microscleres are oxyhexasters (126–252 µm
in diameter) and two types of discohexasters (16–25 and
30–56 µm in diameter).
Zoogeographic distribution. North Pacific Ocean;
locally common and abundant in some areas. Alaska –
Bering Sea to Southeast Alaska. Elsewhere – Japan to
Baja Mexico.
Habitat. Aleutian Islands – attached to cobbles and
pebbles (low-relief habitat) and sometimes bedrock
(high-relief habitat) at depths between about 100 and
756 m. Bering Sea – attached to cobbles and pebbles at
depths between 373 and 522 m. Gulf of Alaska – principally
on bedrock, but also boulders and cobbles on the
continental shelf and upper slope at depths between
140 and at least 228 m. Observed in the glacial fiords
21
of Southeast Alaska growing on bedrock at depths as
shallow as 20 m. Elsewhere – Lamb and Hanby (2005)
provide a worldwide depth range of 10 and 1600 m.
Remarks. This is one of the most ecologically important
sponges in Alaska and perhaps the most thoroughly
studied sponge species in the North Pacific Ocean. Due
to its rigid skeleton, this species is an important structural
component of the sponge reefs reported along
the Pacific Coast of Canada (Conway et al., 1991, 2005;
Krautter et al., 2001) and more recently in southern
Southeast Alaska. Juvenile golden king crabs (Lithodes
aequispina) use the spongocoel as refuge habitat in
the Aleutian Islands (Stone, 2006) and in the Bering
Sea Canyons (Stone, unpubl. data, 2007). The bigmouth
sculpin (Hemitripterus bolini) deposits its eggs in
the spongocoel in the Bering Sea and Gulf of Alaska
(Busby 3 ). This species is preyed upon by the sea stars
Hippasteria spp. and Poraniopsis inflata in the eastern
Gulf of Alaska. Aphrocallistes vastus can be distinguished
from the very similar Heterochone calyx calyx by the lack
of pinular hexactins on the inner (atrial) surface and by
the possession of very robust oxyhexasters with primary
rays subsumed in the swollen centrum.
Photos. 1) Specimen collected at a depth of 168 m
in the eastern Gulf of Alaska. Grid marks are 1 cm 2 . 2)
Specimen with a juvenile golden king crab (Lithodes
aequispina) in pre-molt condition at a depth of 190
m in the central Aleutian Islands. 3) Specimen with a
swarm of euphasiids at a depth of 170 m in the eastern
Gulf of Alaska. Photo by J. Lincoln Freese (AFSC). 4)
Specimen at a depth of 190 m in the central Aleutian
Islands. 5) Specimen at a depth of 20 m with Eualas sp.
shrimp in Glacier Bay National Park, Southeast Alaska.