Hymedesmia pilata

Bowerbank, 1882

Species Overview

Hymedesmia pilata Bowerbank, 1882 is a very thinly encrusting, slightly hispid sponge recorded only once from the W coast of Ireland. Live colour is unknown. It stands out among other Hymedesmia species in the absence of chelae (microscopic examination).

Taxonomic Description

Colour: Dark amber-brown in the dry state.
Shape, size, surface and consistency: Very thinly encrusting. Surface smooth or minutely hispid. Small dispersed oscules.
Spicules: (Hymedesmia pilata spics) (Hymedesmia pilata Burton) Megascleres: Ectosomal tornotes strongylote: 120 x 1.5 µm; acanthostyles in a large size range but not divisible in two categories, spines most pronounced at the base: 78-240 x 8-9 µm.
Microscleres : Sigmas of two size categories: 15 µm and 30 µm.
Skeleton: Bundles of 2-3 tornotes or single tornotes and erect acanthostyles make up most of the skeleton; the surface carries large numbers of sigmas.
Ecology: No data.
Distribution: Recorded once form Birterbuy Bay, W coast of Ireland.
Etymology: Pilatus (Latin) = densely hairy, referring to the skeleton.
Type specimen information: The type is in the Natural History Museum, London.

Remarks

This species is known only from a single specimen from the W coast of Ireland. The original description failed to mention the presence of strongylote tornotes. This led Lundbeck (1910) to conclude that pilata probably was an Eurypon ; however, that genus does not have sigmas and belongs to a suborder (Microcionina) which is entirely devoid of sigmas. In most respects (except the lack of chelae) pilata corresponds to Hymedesmia .
Source: Burton, 1930b.