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

35. Rhizaxinella clavata (Thiele, 1898)
Description. Thin stalk terminates in a globular or
oval body. Species is similar to Stylocordyla borealis eous.
This species has a slightly thicker stalk which widens towards
the body and a strongly hispid surface of the body
compared to the smooth surface of S. borealis eous. Spicules
are arranged radially in the interior of the sponge
with dense spicule brushes at the surface. Length is up
to 5.5 cm. Color in life is golden brown.
Skeletal structure. There are tylostyles to subtylostyles
(1050–1780 × 15–32 µm) and smaller tylostyles
(180–370 × 6–10 µm).
Zoogeographic distribution. Uncommon. In Alaska
– Bering Sea (Zhemchug Canyon). Elsewhere – the
holotype was recorded from the Sea of Japan.
Habitat. In Alaska – attached to hexactinellid sponge
skeletons at a depth of 915 m. Elsewhere – reported on
mud bottoms at a depth of 183 m.
Remarks. Rhizaxinella clavata can be distinguished
from the similar Stylocordyla borealis eous by its thicker
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stalk and hispid oval body. Also, R. clavata has tylostyles
and subtylostyles while S. borealis eous has exclusively
centrolyte oxeas.
Photo. 1) Specimen collected at a depth of 915 m in
Zhemchug Canyon, Bering Sea. Specimen is attached to
an unidentified hexactinellid sponge skeleton.