Marine Species Identification Portal : Phakellia robusta

Bowerbank, 1866

Species Overview

Phakellia robusta Bowerbank (1866) is an ochre-yellow, thin, fan-shaped sponge with smooth surface. It is similar to the more common P. ventilabrum but differs in having sinuous oxeas in stead of sinuous strongyles (microscopic examination). It is a northern deep-water species.

Taxonomic Description

Colour: Ochre-yellow in dry condition.
Shape, size, surface and consistency: Thin-bladed fans. Height and width up to 11-12 cm. Surface optically smooth, slightly hispid to the touch. Oscules not apparent. Consistency flexible.
Spicules: Styles slightly curved: up to about 1000 x 20 µm. Oxeas in two categeories, one short, curved rather strongly but only once: 400-500 x 10 µm; the second are vermiform, doubly or multiply curved: up to about 800-1000 x 10-15 µm.
Skeleton: A reticulation of spicule bundles and interconnecting single spicules. Longitudinal bundles cored by vermiform oxeas; styles in echinating and connecting positions.
Ecology: Deep water, 81-810 m
Distribution: Norway, Shetlands, SW Ireland; Mediterranean(?), Azores.
Etymology: The name refers to the spicules that are more robust than those of P. ventilabrum.
Type specimen information: The type is in the Natural History Museum, London.

Remarks

This species is quite similar to the common Phakellia ventilabrum, and it is not entirely clear whether they belong indeed to different species. The major difference is the oxeote nature of the sinuous spicules (as opposed to strongylotes inventilabrum).
Phakellia hirondelli (Topsent, 1892a) from deep water (110-1200 m) is similar to P. robusta in most respects, but Boury-Esnault et al. (1994) maintain the two are clearly different; one is referred to this publication for further details.
Source: Arndt, 1935.

Phakellia robusta