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

100 Professional Paper NMFS 12
83. Guitarra abbotti Lee, 1987
Description. This sponge is subglobular and massive.
Consistency is elastic, soft, and easy to tear. Oscula are
small, circular, and slightly elevated on short conical
projections. The surface is smooth to the unaided eye
but microscopically hispid or brain-like with narrow
convolutions. Diameter is to 15 cm. Color in life is yellow,
orange, or dark brown.
Skeletal structure. SEM images of spicules are shown
in Appendix IV. There is no specialized ectosomal skeleton;
the dermal membrane consists of spicule brushes
at the ends of short polyspicular tracts, ascending only
a short distance from the choanosome. Sections parallel
to the surface show the regularly spaced spicule brushes
up to 300 µm in diameter. Short polyspicular tracts of
styles make up a relatively dense but irregular meshwork
in the choanosome, mesh-size 100–200 µm, with single
spicules scattered in between. The short length of the
tracts gives a halichondroid appearance throughout
much of the choanosome. Megascleres are fusiform
styles (330–400 × 7–10 µm). There are seven types of
microscleres: large placochelae (105–115 µm); small
placochelae (30–50 µm); large biplacochelae (35–52
µm); small and relatively rare biplacochelae (13–16 µm
in diameter); a rare, large category of isochelae (58-
65 µm); small sigmoid isochelae (10–13 µm) almost
closed; and small sigmoids (5–9 µm). All spicule-types
are distributed without an obvious pattern throughout
the sponge.
Zoogeographic distribution. North Pacific Ocean.
Locally common. In Alaska – central Aleutian Islands.
Elsewhere – previously known only from Cordell Bank,
California.
Habitat. In Alaska – attached to cobbles at depths between
100 and 146 m. Elsewhere – reported at depths
between 35 and 46 m.
Photos. 1) Specimen collected at a depth of 138
m in the central Aleutian Islands. Grid marks are 1
cm 2 . 2) Same specimen as in photo 1 in situ (center).
3) Specimen (center) collected at a depth of 146 m in
the central Aleutian Islands.