(Burton, 1930a)
Species Overview
Clathria (Microciona) bitoxa (Burton, 1930a) is a thinly encrusting sponge belonging to the large group of Clathria (Microciona ) species which can only be reliably identified by microscopic examination. It lacks chelae. It is known only from Scandinavian waters.
Taxonomic Description
Colour: Pale brown in alcohol.
Shape, size, surface and consistency: Thinly encrusting, pores and oscules not apparent.
Spicules: Megascleres : Ectosomal subtylostyles, smooth, with a crown of small spines at the base: 600 x 5 µm; long styles, smooth: 900-1200 x 15 µm; small entirely spined acanthostyles: 60 x 5 µm.
Microscleres : Toxas of two kinds, short stout, variable in size: 30-105 x 4 µm, and long hair-like forms: 150 µm.
Skeleton: Hymedesmoid: long styles and acanthostyles with their bases embedded in a basal plate of spongin; ectosomal subtylostyles form an irregular tangential layer at the surface. Small toxas scattered irregularly throughout the sponge; hair-like toxas forming wisp-like bundles.
Ecology: No data.
Distribution: Norway, West coast of Sweden.
Etymology: The name refers to the two kinds of toxas.
Type specimen information: BMNH 1910.1.1.787V (wet). Norman Collection.
Remarks
The species was erected as member of a genus Hymantho Burton (1930) based on the absence of chelae. In view of the variability of the presence of chelae in the order Poecilosclerida, this genus is considered artificial. A second species of Clathria lacking chelae is C . normani Burton, 1930a, differing in having much smaller styles and only a single toxa category.
Source: Burton, 1930a.