Hymedesmia veneta

(Schmidt, 1862)

Species Overview

Hymedesmia veneta (Schmidt, 1862) is a thinly encrusting sponge originally described from the Mediterranean, but subsequently recorded only twice, from the W coast of Ireland and the S coast of England. Its live colour is unknown, but it stands out among the other Hymedesmia species in the small size of the chelae (microscopic examination).

Taxonomic Description

Colour: Cream-white in the dry state.
Shape, size, surface and consistency: Thinly encrusting. Size up to about 1 cm2. Surface smooth. Oscules small.
Spicules: (Hymeniacidon armiger spics) Megascleres : Ectosomal tornotes fusiform, oxeote: 175 x 3 µm; acanthostyles entirely spined, in a large size range but not divisible in categories: 75-220 µm.
Microscleres : Arcuate chelae 12-17 µm.
Skeleton: Presumably hymedesmoid, but described as confused.
Ecology: Encrusting maerl, shells etc.
Distribution: Roundstone, W coast of Ireland; Plymouth; Mediterranean.
Etymology: Venetus (Latin) = sea-blue, presumably referring to the colour of the type.
Type specimen information: The type is in the Berlin Museum, ZMB 4605 (a slide is in the BMNH, reg.no. 1867:3:11:88)

Remarks

The small size of the chelae form the characteristic feature of the species.
Source: Bowerbank (1882).