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

16 Professional Paper NMFS 12
4. Farrea kurilensis ssp. nov. Reiswig and Stone, in preparation
Description. Lace-like mass has large-caliber (2-cm
diameter), short, branching, and anastomosing tubes
increasing in size (of the mass) by lateral growth, conforming,
and attaching at multiple sites to the hard
substrate and not growing erect. Surface of the mass
is labyrinthic, but that of individual tube elements is
smooth. Open terminal ends of tubes are effectively
oscula. Consistency is flexible but brittle due to fusion
of the very thin primary skeleton. Individuals observed
in situ have a diameter of 170 cm. Color in life is translucent
light blue to white.
Skeletal structure. The primary framework is a fused
farreoid lattice of hexactins forming a network of square
meshes with sides 439–750 µm long; it is continuous
throughout the specimen. Loose megascleres include
dermal and atrial pentactins, often with knobs or very
short distal rays (170–375 µm tangential ray length,
211–422 µm proximal ray length); very large anchorate
clavules with completely smooth shafts (302–1243
µm length); moderate-sized uncinates (1.03–2.99 mm
length); very rare choanosomal hexactins (208–239
µm ray length). Microscleres consist of two size classes
of stellate discohexasters (30–89 µm and 91–293 µm in
diameter).
Zoogeographic distribution. Locally common and
abundant in some areas. In Alaska – central Aleutian
Islands. Elsewhere – not reported.
Habitat. Attached to bedrock, mudstone, boulders,
cobbles, and hexactinellid sponge skeletons at depths
between 300 and 2249 m.
Remarks. Farrea kurilensis presently has two subspecies:
F. k. kurilensis, which occurs near the Kuril Islands
and in the Sea of Okhotsk, has smooth pileate clavules,
while F. k. beringiana, which also occurs near the Kuril
Islands, has all clavules with spines. The new Aleutian
subspecies differs from these in having anchorate clavules
with smooth shafts and an alternate microsclere
combination.
Photos. 1) Preserved (frozen then dried) fragment of
a specimen collected at a depth of 2105 m in the central
Aleutian Islands. Grid marks are 1 cm 2 . 2) The same
specimen as in photo 1 in situ.