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

120 Professional Paper NMFS 12
100. Halichondria (Halichondria) oblonga (Hansen, 1885)
Description. This cylindrical, tube-shaped sponge
has a narrow stalk. It may branch near the base of the
stalk so that several tubes (up to 12) may be connected
basally. Consistency is only slightly elastic and stiff. Near
the base the tubes are 3–4 mm in diameter and widen
to a maximum diameter of 2 cm. Maximum height is to
18 cm. Color in life is golden brown with a light, almost
whitish tip.
Skeletal structure. The brown part of the sponge
is more stiff and covered with an ectosomal layer of
densely packed, parallel arranged tangential oxeas. The
whitish tip of the sponge is covered by a thin dermal
membrane without spicules. Choanosomal ascending
paucispicular tracts are connected by single spicules.
Oxeas are 320–480 × 14–20 µm.
Zoogeographic distribution. Widespread and locally
abundant. In Alaska – central Aleutian Islands.
Elsewhere – Arctic Ocean (Barents Sea and Kara Sea)
and North Atlantic Ocean (Greenland and the Faroe
Islands).
Habitat. In Alaska – patchy distribution; attached
to hard substrate (generally cobbles and pebbles) at
depths between 115 and 305 m. Elsewhere – reported
at depths between 18 and 823 m.
Photos. 1) Specimens collected with the demosponge
Myxilla behringensis (left center) at a depth of 195 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Same specimens as in photo 1 in situ. 3) Cluster of
specimens (lower center) below the golden king crab
(Lithodes aequispina) at a depth of 272 m in the central
Aleutian Islands.