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

66 Professional Paper NMFS 12
50. Artemisina arcigera (Schmidt, 1870)
Description. This sponge is stalked and tube-shaped
in the Aleutian Islands, but Koltun (1959) described
this species as cushion-shaped, spherical, or somewhat
elongated, and up to 5.5 cm in height. The surface of
the sponge is smooth at the stalk and gradually changes
from hispid to rugose in the lower half and is smooth
again in the apical region. No oscula are visible. The
consistency of the stalk is wiry and gets softer along its
length. In areas of water current this species typically
bends over near the base and sometimes lies in contact
with the seafloor. Stalked forms are to 31 cm in height
and 7 cm in width. Color in life is brown to golden
brown.
Skeletal structure. There are ectosomal brushes of
smaller subtylostyles (280–428 × 9–18 µm); choanosomal
large subtylostyles (430–676 × 6–9 µm), occasionally
with acanthaceous heads; palmate isochelae (6–15 µm);
and toxas with acanthaceous ends (60–360 µm).
Zoogeographic distribution. Widespread and locally
common. In Alaska – central Aleutian Islands. Elsewhere
– widely distributed in the Arctic Ocean (Barents
Sea – White Sea, Kara Sea – Vilkitsky Strait, Greenland
Sea – Island of Spitsbergen) and Northeast Atlantic
Ocean (Norwegian Sea, Denmark Strait, Davis Strait).
Habitat. In Alaska – attached to cobbles and pebbles
at depths between 170 and 436 m. Elsewhere – reported
at depths between 14 and 1000 m and temperatures
between 1.4 and 5.0°C.
Remarks. Specimens from the Aleutian Islands differ
in form from previous records but the spicule
complement (types and size ranges) of the specimens
conform perfectly to A. arcigera so we assume they are
a previously unreported growth form of the same species.
The shrimp Eualus barbatus is often associated with
this sponge.
Photos. 1) Specimen collected at a depth of 192 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Same specimen as in photo 1 in situ (center).
3) Same specimen as in photos 1 and 2 showing details
of the rugose surface and apical region.