Dendoricella flabelliformis

(Hansen, 1885)

Species Overview

Dendoricella flabelliformis (Hansen, 1885) is a brownish, broadly erect, leaf-shaped sponge. Rather soft in consistency with uneven surface. It spiculation of oxeas and arcuate isochelae is unique (microscopic examinaton). It is a northern deep water species.

Taxonomic Description

Colour: Light brownish grey in alcohol.
Shape, size, surface and consistency: Erect, broad, leaf-shaped sponge. Size up to 9 cm high and wide. Surface rather rough. Oscules on the rim. Consistency rather soft.
Spicules: (Dendoricella flabelliformis sp ) Megascleres : Oxeas only, in two size categories: choanosomal oxeas 410-550 µm, ectosomal oxeas 268-350 µm.
Microscleres : Arcuate isochelas, robust, strongly curved, with alae often almost touching, sometimes slight asymmetric: 30-40 µm.
Skeleton: Ectosomal : brushes of oxeas, scattered single oxeas. Choanosomal : plumose bundles of oxeas, sparingly connected by single oxeas; spongin visible only in the stalk.
Ecology: Deep water, 90-1097 m.
Distribution: Norway; Arctic.
Etymology: The name refers to the shape of the species.
Type specimen information: No data.

Remarks

This species is usually assigned to Isodictya , because of the spiculation of oxeas and chelae. However, the type of Isodictya , I . palmata , has palmate isochelae and the skeleton is strictly anisotropic, whereas flabelliformis has arcuate isochelae and the skeleton is more plumose.
Source: Arndt, 1935.