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

88 Professional Paper NMFS 12
72. Stelodoryx toporoki Koltun, 1958
Description. This sponge is stalked, flabellate, or a
somewhat flattened funnel. Consistency is elastic with a
thin ectosomal membrane. It is soft and floppy in situ.
Height is to 17 cm and width to 12 cm. Color in life is
light yellow; dark brown after freezing.
Skeletal structure. Ectosomal tylotes have acanthaceous
ends (218–300 × 8–10 µm). Choanosomal styles
(500–1140 × 21–30 µm) occasionally have acanthaceous
heads, and anchorate isochelae are in two size categories
– large (115–150 µm) and small (30–40 µm).
Zoogeographic distribution. Locally common in
the North Pacific Ocean. In Alaska – central Aleutian
Islands. Elsewhere – Sea of Okhotsk (near the Kuril
Islands).
Habitat. In Alaska – occurring in small patches (up to
5 individuals per m 2 ) on bedrock, mudstone, boulders,
and cobbles at depths between 1714 and 2314 m. Elsewhere
– found on sand, pebbles, and “reefs” at depths
between 113 and 303 m and at temperatures between
1.8 and 3.1°C.
Remarks. A sponge with similar appearance except
larger (up to 50 cm diameter) and more robust (forming
distinct bowls) occurs at depths between 1185 and
1540 m. Collection of a specimen within this depth
range and examination of the spicules is necessary to
confirm conspecificity, however.
Photos. 1) Preserved (frozen) specimen collected at
a depth of 2176 m in the central Aleutian Islands. Grid
marks are 1 cm 2 . 2) Same specimen as in photo 1 (lower
center) in situ. 3) Close-up view of specimen in situ at a
depth of 1505 m in the central Aleutian Islands.