Psammocinia cf. arenosa ( Lendenfeld, 1888 )

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 : 65-67

Psammocinia cf. arenosa ( Lendenfeld, 1888)

( Fig. 29 A–H)

Synonomy

Hircinia (Psammocinia) arenosa Lendenfeld, 1888 p. 181;

Hircinia (Psammocinia) arenosa Lendenfeld, 1889 p. 583, pl. 36, fig. 3;

Psammocinia arenosa Bergquist, 1980 p. 468, fig. 9B.

Material examined. SAMC–A24784 (cross-reference TS 843 & Saf 03- Sod 83), Deep-sponge reef, Sodwana Bay (27.5167°S, 32.6835°E), South Africa 0 6 November 2003, collected by T. Samaai, depth 30 m. SAMC–A24785 (cross-reference TS 865 & Saf 03- Sod 41), Gotham reef, Sodwana Bay (27.4917°S, 32.7022°E), South Africa 0 5 November 2003, collected by T. Samaai, depth 34 m. SAMC–A24786 (cross-reference TS 892 & Saf 03- Sod 13), Ramsay reef, Sodwana Bay (27.4467°S, 32.7152°E), South Africa 0 3 November 2003, collected by T. Samaai, depth 18 m. SAMC–A24787 (cross-reference TS 918 & Saf 03- Sod 45), Gotham reef, Sodwana Bay (27.4917°S, 32,7022°E), South Africa 0 5 November 2003, collected by T. Samaai, depth 34 m. SAMC–A24788 (crossreference TS 923 & Saf 03- Sod 68), Two Mile reef, Sodwana Bay (27.5167°S, 32.6835°E), South Africa 0 5 November 2003, collected by T. Samaai, depth 12 m.

Description. Large cup-shaped, symmetrical or low, flat and irregular sponge ( Fig. 29 A–E). Cup-shape sponge attached to the substratum by a narrow base. Walls of cups of uniform thickness. Surface rugose and undulating with upper side many small randomly scattered ostia visible, ± 0.5 mm in diameter. Texture firm, heavy crust of very fine sand present, non-compressible, difficult to tear. Colour in life dark grey-black; in preservative grey.

Skeleton ( Fig. 29 F–H). Choanosomal skeleton consists of irregular primary fibres cored with foreign material, 320 (260–410) µm in diameter. Secondary fibres are fasciculate, 96 (43–135) µm in diameter, cored near the ectosome, and connected by wide areas of spongin. A secondary web of spongin is found in the choanosome with perforations. A dense mass of fine collagenous filaments, each enlarged terminally at both ends, occurs in the mesohyl.

Substratum, depth range and ecology. Found growing in coral rubble, in and around areas of sand, depth range 12–34 m

Geographic Distribution. South and East coasts of South Africa.

Remarks. Psammocinia species possess a sand-armoured surface, a pronounced organized sandy ectosome, and a regular, reticular fibre skeleton, with a hierarchy of concentrically laminated primary and secondary fibres ( Cook and Bergquist 1998). The genus consists of 19 species distributed mainly in the Indo-Pacific and Korea. The sponge described here agrees well with the description of P. arenosa provided by Cook & Bergquist (1998) from Australia and that of Kirkpatrick (1903) from South Africa. Psammocinia arenosa are cup-shaped, attached to the substratum with a narrow base, have walls of uniform thickness and are incompressible with a thick crust of sand. Their description of P. arenosa ’s skeleton included irregular cored primary fibres, 200 µm in diameter and secondary fibres, 50 µm in diameter, which may show coring. This is similar to the sponge described here. Psammocinia amodes ( Cook & Bergquist, 1998) is similar to P. arenosa but is distinguished by thin sand armour and a digitate to spatulate form ( Cook & Bergquist 1998). Classifying this sponge fully as P. arenosa is difficult due to its distribution in South Africa. No other Psammocinia species are described here or in the WIO. Due to its similarity to P. arenosa , this sponge is regarded as Psammocina cf. arenosa .

Key diagnostic characters.

• Sponge large, cup-shaped.

• Texture firm, heavy crust of very fine sand present.

• Primary fibres thick and cored with foreign material.

• A dense mass of fine collagenous filaments, each enlargened terminally at both ends, occurs in the mesohyl.

Figures

FIGURE 29. Psammocinia cf. arenosa (Lendenfeld, 1888). A-E. In situ; F-H. Skeletal architecture (F, x5; G, x10, H, 40)