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

30 Professional Paper NMFS 12
16. Acanthascus (Staurocalyptus) sp. nov. 1 Reiswig and Stone, in preparation
Description. This species grows from a narrow attached
base to either a thick massive or thick funnelshaped
form. External surface has small rounded
protuberances from each of which project several short
diactin prostalia; there is a single large terminal osculum.
Consistency is soft and easily torn. Height is up to
24 cm and diameter to 17 cm. Color in life is brown to
golden brown.
Skeletal structure. Skeleton is composed entirely of
loose spicules. Megascleres are thick prostal diactins
(4.3–10.1 mm long), a few rough, but not thorned,
hypodermal pentactins (0.21–1.09 mm tangential ray
length); principal diactins (1.11–6.84 mm long); dermal
hexactins with some pentactins and stauractins
(40–139 mm ray length); atrial hexactins (43–218 mm
ray length). Microscleres are oxyhexactins and a few
hemioxyhexasters (86–175 mm in diameter); very small
discoctasters with terminals strongly curved outward
(56–87 mm in diameter); microdiscohexasters are
absent.
Zoogeographic distribution. Locally abundant.
In Alaska – central Aleutian Islands. Elsewhere – not
reported.
Habitat. Attached to cobbles and pebbles at depths
between 139 and 183 m.
Remarks. This species is distinguished from all other
species of Acanthascus (Staurcalyptus) by the small size
and shape of its discoctasters. A complete description
is in preparation.
Photos. 1) Partially fragmented specimen collected
with a trawl at a depth of 155 m in the central Aleutian
Islands. Grid marks are 1 cm 2 . 2) Specimen at a depth
of 165 m in the central Aleutian Islands.