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

51. Artemisina stipitata Koltun, 1958
Description. This sponge is flabellate in the Aleutian
Islands but spherical and lobate forms have been
reported elsewhere. It is basally stalked and gradually
tapers to a holdfast. Conspicuous oscula are present on
dorsal surfaces. The stalk is cylindrical and rigid. The
body is soft and elastic. Height and width are at least 50
cm. The ectosome is yellow or light brown. The choanosome
is orange-brown.
Skeletal structure. Ectosomal skeleton has tangentially
arranged small styles with acanthose heads (220–340
× 6–10 µm). The reticulate choanosomal skeleton has
fusiform styles with acanthose heads (460–510 × 18–25
µm). Microscleres are palmate isochelae (10–19 µm).
Zoogeographic distribution. Locally abundant. In
Alaska – central Aleutian Islands. Elsewhere – previously
known from only two specimens collected in southern
Kuril Strait until discovered in the central Aleutian
Islands in 2004.
Habitat. In the Aleutian Islands – attached to bedrock
outcrops, boulders, and cobbles at depths between 80
and 239 m on shelf and upper slope habitats. Elsewhere
– no information available.
Remarks. It is similar in appearance to Tedania kagalaskai,
with which it co-occurs. The dorsal surface of A.
stipitata is typically more rounded than T. kagalaskai and
the body form of the latter species is much smoother
and more distinctly triangular. A. stipitata is often associated
with the gorgonian Fanellia compressa.
Photos. 1) Specimen collected at a depth of 150 m
in the central Aleutian Islands. Grid marks are 1 cm 2 .
2) Same specimen as in photo 1 in situ showing the
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detail of the oscula on the dorsal surface. 3) Specimen
observed in situ at a depth of 87 m in the central Aleutian
Islands. 4) Specimen observed in situ at a depth of
105 m in the central Aleutian Islands. A juvenile king
crab uses the sponge as a perch.