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