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

98 Professional Paper NMFS 12
81. Biemna variantia (Bowerbank, 1858)
Description. This sponge is subglobular. Surface is
covered with numerous papillae. Oscula are at the top
of the sponge in clusters. It is very soft, fragile, and easily
torn. Diameter is to 10 cm. Color in life is greenish yellow
to light brown; brown or dark brown after freezing.
Skeletal structure. A thin ectosomal membrane contains
only microscleres. There are styles (420–1450
× 18–35 µm), sigmas possibly in two size categories
(40–310 µm), rhaphides (60–125 µm), and spherules
(10 µm). Long ascending and branching polyspicular
tracts of styles in the choanosome have many spicules
scattered between the tracts.
Zoogeographic distribution. Widespread but uncommon.
In Alaska – central Aleutian Islands. Elsewhere
– North Pacific Ocean (Bering Sea – Russia), Arctic
Ocean (Barents Sea and Greenland Sea), and North
Atlantic Ocean (eastern Scotian Shelf east to Iceland
and south to the Canary Islands; western Mediterranean
Sea).
Habitat. In Alaska – attached to cobbles and pebbles
at depths between 155 and 489 m. Elsewhere – reported
at depths between 62 and 1800 m depth.
Photos. 1) Specimen collected at a depth of 155 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Preserved specimen (frozen) collected at a depth of
489 m in the central Aleutian Islands. Grid marks are 1
cm 2 . 3) Same specimen as in photo 2 (indicated by the
white arrow) in situ.