Euryspongia coeruleum, Samaai & Pillay & Janson, 2019

Samaai, Toufiek, Pillay, Ruwen & Janson, Liesl, 2019, Shallow-water Demospongiae (Porifera) from Sodwana Bay, iSimangaliso Wetland Park, South Africa, Zootaxa 4587 (1), pp. 1-85 : 72-74

Euryspongia coeruleum sp. nov.

( Fig. 33 A–E)

Material examined. Holotype. SAMC–A24795 (cross-reference TS 838 & Saf 03-Sod 32), Five Mile reef, Sodwana Bay (27.495°S, 32.6902°E), South Africa, 0 3 November 2003, collected by T. Samaai, depth 24 m.

Paratype. SAMC–A24796 (cross-reference TS 952 & Saf 03-Sod 65), Two Mile reef (27.5167°S, 32.6835°E), Sodwana Bay, South Africa, 0 5 November 2003, collected by T. Samaai, depth 12 m.

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

Description. Massive branching sponge, 90 × 57 × 80 mm diameter, body attached to a broad base ( Fig. 32A ). Surface unarmoured, extremely conulose with fibrous projections 2–4 mm high. Oscules sunken, 10–15 mm in diameter; ostia, 0.5–3 mm in diameter, dispersed over the entire surface. Texture soft, very compressible. Colour in life pale blue; in preservative light-brown.

Skeleton ( Fig. 32 B–E). Choanosomal skeleton consists of cored primary fibres and an irregularly disposed network of clear secondary fibres. Primary fibres, 92 (80–103) µm in diameter; secondary fibres, 27 (24–30) µm in diameter. Primary fibres run longitudinally; the secondary network is irregular and branching. Secondary fibres clear and primary fibres slightly stratified. Sand particles incorporated in the mesohyl.

Substratum, depth range and ecology. This species is found in and amongst corals on rocky ledges at a depth range between 12– 24 m.

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

Etymology. Named for the sky blue colouration of the sponge ( coeruleum , meaning sky blue, L.).

Remarks. This sponge falls into the genus Euryspongia due to a skeleton of cored primary fibres and uncored secondary fibres, which also form a secondary reticulation, and a soft, branching external morphology. This is the first record of this genus in South Africa. This genus is relatively new consisting of 11 species, of which 10 were initially placed in the genus Spongia . These sponges closely approach the genus Spongia with only difference being the eurypylous chambers ( Row 1911). The key characters that distinguish Euryspongia from other dysideid genera are the soft consistency and development of the secondary fibre reticulum (Cook & Berquist 2002). Euryspongia lactea Row, 1911 , documented in the WIO, is similar to E. coeruleum sp. nov. in fibres dimensions. It differs from E. coeruleum sp. nov. in having an irregular, subspherical external morphology and milky white colouration. Euryspongia raouchensis Vacelet, Bitar, Carteron, Zibrowius & Perez, 2007 is thickly encrusting and pigmented cream. It possesses larger primary (125–150 µm) and secondary (40–70 µm) fibres ( Vacelet et al. 2007). The incorporation of sand in the sponge mesohyl, the lightly stratified primary fibres and unstratified clear secondary fibres, branching morphology and aqua blue colouration of E. coeruleum sp. nov. differentiate this species from other species of Euryspongia .

Key diagnostic characters.

• Sponge massive branching with sunken oscules.

• Primary fibres run longitudinally, whereas the secondary network branching.

• Milky white colouration.

Figures

FIGURE 32. Spongia (Heterofibria) smaragdus sp. nov. A-C. In situ; D-F. Skeletal architecture (D, x5; E, x10; F, x40)

FIGURE 33. Euryspongia coeruleum sp. nov. A. In situ; B-E. Skeletal architecture (B, x5; C, x5; D, x10; E, x40)