Iophon piceus

(Vosmaer, 1882b)

Species Overview

Iophon piceus (Vosmaer, 1882b) is a brown to blackish leaf-shaped or cup-shaped sponge with irregular rim and a grooved surface. It is soft and easily damaged. It is a northern deep-water species.

Taxonomic Description

Colour: Dark brown to blackish (alcohol), possibly lighter coloured.
Shape, size, surface and consistency: Leaf-shaped, or irregularly cup-shaped. Size up to 16.5 cm high; leaf thickish. Surface grooved, irregular, but otherwise smooth. Oscules and pores in grooves on opposite sides of the leaf surface. Consistency soft, easily damaged.
Spicules: (Iophon piceus spics) Megascleres : Ectosomal tylotes with extensively spined heads: 218-311 x 5-10 µm; acanthostyles, in a large size variation but not distinguished in two categories, curved, variably spined all over or only sparingly near both ends: 239-450 x 15-36 µm.
Microscleres : Spurred anisochelae, of variable size, possibly in two size categories: 15-36 µm; bipocillae, rounded, with numerous fine teeth on the rims, in a single category: 8-14 µm.
Skeleton: Ectosomal skeleton is made up of tylote brushes, which are partially tangential arranged in intercrossing bundles. Choanosomal skeleton a rather tight-meshed multispicular isotropic reticulation, rather irregular, with little binding spongin.
Ecology: In deep water: 80-1785 m.
Distribution: Norway, Sweden, Faroes, Arctic.
Etymology: Piceus (Latin) = pitch-black, referring to the colour.
Type specimen information: The type is in the Zoological Museum of Amsterdam, ZMA POR. 410.

Remarks

This species has been variously divided up into four subspecies (Koltun, 1959) or synonymized with Iophon nigricans . It admittedly is close to the latter, but in view of the distinct upright leaf-shaped growth form and the distinctly larger acanthostyles it is proposed here to keep piceus as a separate species.
Source: Arndt, 1935.