''Ascandra izuensis'' is a
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
sea sponge
Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a basal clade and a sister taxon of the diploblasts. They are sessile filter feeders that are bound to the seabed, and are o ...
in the family
Clathrinidae
Clathrinidae is a family of calcareous sponges in the order Clathrinida. It contains the following genera:
*''Arturia''
*'' Ascilla''
*'' Borojevia''
*'' Brattegardia''
*''Clathrina
''Clathrina'' is a genus of calcareous sponge in the family ...
. The species is named after the
Izu peninsula
The is a mountainous peninsula with a deeply indented coastline to the west of Tokyo on the Pacific Ocean, Pacific coast of the island of Honshu, Japan, the largest of the four main islands of Japan. Formerly known as Izu Province, Izu peninsu ...
where the holotype was collected.
Description
''Ascandra izuensis'' is a
calcareous sponge
The calcareous sponges or calcereans are sponges that make up the class Calcarea, characterized by spicules made of calcium carbonate in the form of high-magnesium calcite or aragonite. While the spicules in most species are triradiate (with three ...
. It is found in the Central Kuroshio Current,
Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
.
The sponge consists of loosely branched and anastomosing ascon-tubes directly attached to a substratum. There is no pseudoderm covering the whole colony and no endogastric network. The sponge is rather small and attains a length of about 6 mm. The diameter of the ascon-tubes varies from 0.3 mm to 1 mm and the dermal surface of the tubes have a hispid appearance on account of projecting oxea. The colour of the sponge is yellowish-white when preserved in alcohol.
The skeleton of the sponge is composed of triradiates, large and small quadriradiates, and oxea. The tri- and quadriradiates are arranged in a few layers in the sponge wall. The quadriradiates are more numerous than the triradiates and their apical rays project into the gastral cavity. The larger quadriradiates are usually arranged in the dermal skeleton. The oxea occur vertically or obliquely to the surface of the ascon-tubes.
References
izuensis
Sponges described in 1942
Invertebrates of Japan
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