Psammocinia alba sp. nov.

(Fig. 30 A–C)

Material examined. Holotype. SAMC–A24789 (cross-reference TS 934 & Saf 03-Sod89), Seven Mile reef, Sodwana Bay (27.4581°S, 32.7141°E), South Africa, 0 7 November 2003, collected by K. Sink, depth 23 m.

Paratype. SAMC–A24790 (cross-reference Ts 941 & saf 03-sod102), Seven Mile reef, Sodwana Bay (27.4581°S, 32.7141°E), South Africa, 0 7 November 2003, collected by K. Sink, depth 23 m.

Type locality. Seven Mile, Sodwana Bay, east coast of South Africa.

Description. Massive digitate sponge, tubular structures irregular and low, 160 × 140 × 100 mm diameter, body attached to common base (Fig. 30A). Surface conulose, with oscules on low tubular structures, 2–5 mm in diameter. Ostia visible, small, ± 0.5 mm in diameter, randomly scattered over the surface of the sponge. Texture soft and spongy, very compressible, difficult to tear. Colour in life, white with a pale lilac-tinge, interior pale-beige; in preservative white.

Skeleton (Fig. 30B, C). Choanosomal skeleton consists of irregular primary fibres cored with sand granules, 190 (150–210) µm in diameter. Secondary fibres are 85 (51–98) µm in diameter, also cored with sand granules.

Substratum, depth range and ecology. This sponge was found on a rocky overhang at a depth of 23 m.

Geographic distribution. Sodwana Bay, east coast of South Africa.

Etymology. Named for the white colouration of the sponge, due to the presence of abundant sand grains in the surface ( alba meaning white, L.).

Remarks. Kirkpatrick (1903) described two species of Psammocinia from South Africa viz. P. arbuscula and P. arenosa . The new species differs from both species in being whitish in colouration and a thickly encrusting morphology. The primary fibres are also cored with sand granules and the primary and secondary fibres are thinner as found in the other two South African species.

Key diagnostic characters.

• Sponge massive digitate.

• Colour white with a pale lilac-tinge.

• Secondary fibres thin.