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(Topsent, 1892b)

Species Overview

Crella (Yvesia) rosea (Topsent, 1892b) is a rosy orange, lobate or cushion-shaped sponge of up to 30 cm across. The surface of in situ specimens have transparent rounded pore fields and fairly large oscules with swollen darker coloured excurrent canals. In contracted specimens many of these surface details disappear. It occurs on exposed rock surfaces in the shallow sublittoral. This is a southern species occurring commonly along the south and west coasts of the British Isles, along the coasts of France, Spain and Portugal into the Mediterranean.

Taxonomic Description

Colour: A rather watery orange grading into a purplish tinge, often brownish orange or reddish brown; also yellow. Also reported as rose-red.
Shape, size, surface and consistency: Massive-lobose. A series of lobes joined into an extensive sheet to 30 cm or more across and 3 cm thick. Surface more or less transparent with densely packed inhalant pores gathered into groups (areolated porefields). These inhalant areas are quite distinctive as the surface between the pore areas is less transparent. Oscules large, allowing a view of the excurrent channels; terminating lobes of the body. One or two dark exhalant canals run down the sides of the oscular lobes. In contracted preserved specimens this appears as a smooth groove. Contraction considerable, changing the rounded appearence to a more angular one. Consistency fairly soft but quite tough.
Spicules: (Crella rosea spics) Megascleres include tornotes in the form of strongyloxeas: 230-340 x 5 µm, blunt-ending ectosomal acanthostyles: 65-130 x 3-4 µm, entirely covered with very strong conical spines, and choanosomal acanthostyles: entirely spined, typically 125-220 x 6 µm in length. Microscleres are arcuate isochelae, ca. 17-23 µm, found especially at the surface.
Skeleton: The ectosomal skeleton is a dense tangential layer of small heavily acanthose megascleres, the distinctive character of the family Crellidae. The choanosomal skeleton is a plumose system of thick multispicular ascending fibres of consisting of tornotes. Large straight acanthostyles echinate the substrate, and smaller curved (ectosomal) ones are present throughout the body. Spongin may be present in large amounts, encasing the spicules in the ascending fibres.
Ecology: Found on steeply inclined and vertical rock faces in moderately and fully exposed headlands, channels and open coast, 2-108 m.
Distribution: Atlantic coasts of Europe southwards from Norway; Mediterranean. Apparently largely a southern species.
Type specimen information: MCS voucherBELUM: Mc48, Portquin, N. Cornwall.

Remarks

Appearance is characteristic, somewhat reminiscent of Myxilla rosacea. Spicules, especially surface acanthostyles, are very distinctive, and are one of the diagnostic features separating the Crellidae from the Hymedesmiidae. In most Crella species these ectosomal acanthose spicules (either acanthostyles or acanthoxeas) are found only in the dense surface layer, but in this species they are found throughout the body of the sponge.
Descatoire (1969b) distinguished a variety laevigata for specimens with thinner plumose skeletal fibres.
Source: Ackers et al., 1992 (B.E. Picton)

Crella rosea